- TUHS - www.tuhs.org

Re: [TUHS] Serial Interfaces (was ^T and Top)

by Clem Cole

On Tue, May 29, 2018 at 9:10 PM, Dave Horsfall <dave(a)horsfall.org> wrote: > On Wed, 30 May 2018, Johnny Billquist wrote: > > Uh? Say what? What does XON/XOFF flow control have to do with 8bit data? >> > > Err, how do you send data that happen to be XON/OFF? By futzing around > with DLE (which I've never seen used)? Right - you have to escape things and it is a real mess. I have seen some of the SI/SO/DLE stuff in mechanical systems like ticker tape. I never saw a real 8-bit interface try to do it and succeed -- its messy and suspect when data overruns occurs all hell break loose. By the time of 8 bits and speed of 9.6K protocol's like UUCP, or IP over serial did not even bother. I suspect in the old 5-bit baudot code times, it was more popular to get a larger character set, but the speeds were much slower (and the UART not yet invented by Gordon Bell). By the time of the PDP-11, hardware flow was the norm in many (most) interfaces. I never understood why DEC got ^S/^Q happy. You can really see the issues with it on my PiDP-8, running DOS/8 because the flow is done by the OS and its much to late to be able to react. So you get screens full of data before the ^S is proceeded. Once Gordon creates the UART, Western Digital licensed it and made it into a chip which most folks used. DEC started to use the WD chipset in PDP-8 serial interfaces - it always struck me as strange that HW flow was not used more. The KL11/DL11 supported the wires, although the SW had to do the work. As I said, MacNamara supported it in the DH11, if I recall (I don't have the prints in any more), he put an AND gate in the interrupt bit, so the OS does not get an transfer complete interrupt unless the "I'm ready" signal is available from the other side. When I lectured data com to folks years ago, I liked to express the ECMA serial interface in this manner: There are 6 signal wires and one reference (signal) ground: 1. Data XMT (output) 2. Data RCV (input) 3. I'm Alive (output) 4. He's Alive (input) 5. I'm Ready (output) 6. He's Ready (input) Everything else is either extra protocol to solve some other problem, or is for signal quality (*i.e. *shielding, line balancing etc.). The names of which signals match to which actual pins on the ECMA interface can be a little different depending on the manufacturer of the 'Data Communicating Equipment (DCE - *a.k.a.* the modem) and the Data Terminating Equipment (DTE - *a.k.a.* the host). BTW: ECMA and the WE did specify both signal names and the connectors to use and I think the European Telco's did also (but I only ever saw a German spec and it was in German which I do not read). DCE's are supposed to be sockets (female and originally DB25)s and DTE's were suppose to plugs (male). If you actually follow the spec properly, you never have issues. The problem was the a number terminal manufactures used the wrong sex connector, as a lot of them never read the specs [the most famous being the Lear Siegler ADM3 which was socketed like a DCE but pinned as a DTE - probably was it was cheap and thus became very popular). Also to confuse things where it got all weird was how the DCE's handled answering the phone. And it was because of the answering that we got all the messy stuff like Ring, Data Set/Terminal Ready/Carrier and the like. The different DCE manufacturers in different countries had different answer protocols, than the original Bell system. IIRC the original WE103 needed help from host. Support for Auto-answer was a later feature of the WE212. The different protocols are all laid in well in another late 60s/early 70s data com book from an UMass Prof, who's name I now forget (his book is white with black letters called 'Data Communications' , as opposed to MacNamaras dark blue DEC Press book 'Principles of Data Communications'). So ... coming back to Unix for this list... AT&T owned Western Electric (WE) who was the largest US manufacturer of DCE's [see 1949 law suit/the consent decree et al]. In fact at Bell Labs, a lot people using UNIX did not have 'hardwired terminals' - they had a modem connection. So, Unix as a system and tends to have support for DTE/DCE in the manner WE intended it to be as a result. It's not surprising that see it in the solutions that are there. ᐧ

6 years, 11 months

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Control-T (was top)

by Norman Wilson

Back in 1980 or 1981, when I first started hacking on UNIX but still had some TOPS-10 DNA lingering in my blood, I put in a really simple control-T implementation. Control-T became a new signal- generating character in the tty driver; it sent signal 16. Unlike interrupt and quit, it did not flush input or output buffers. Unlike any other signal, SIG_DFL caused the signal to be silently ignored. (I don't remember why I didn't just teach /etc/init and login to set that signal to SIG_IGN by default; maybe I looked and found too many other programs that monkeyed with every signal, maybe I just didn't think of it.) I then wrote a little program meant to be run in the background from .profile, that dug around in /dev/kmem, figured out what was likely nearest-to-foreground process associated with the same terminal, and printed a little status info for that process. It didn't take long for the remaining TOPS-10 DNA to leach away, and besides it is much easier to run some program in another window now that that is almost always possible, so I don't miss it. But I like that idea better than, in effect, hacking a mini-ps into the kernel, even though the kernel doesn't have to do as much work to get the data. I also thought it made more sense to have a general mechanism that could be used for other things. That even happened once. The systems I ran were used, among other things, for developing SMP, the symbolic-manipulation interpreter worked on by Stephen Wolfram, Geoffrey Fox, Chris Cole, and a host of graduate and undergraduate students. (My memory of who deserves credit differs somewhat from that of at least one person named.) SMP, by its nature, sometimes had to spend a substantial time sitting and computing. Someone (probably Wolfram, says my aging memory) heard about the control-T stuff, asked me how to use it, and added code to SMP so that during a long computation control-T would tell you something about what it was doing and how it was progressing. Since the signal was, like interrupt and kill, sent to the whole process group, there was no conflict if you also had my little control-T monitor running in the background. I never tried to send my hacked-up UNIX to anyone else, so if anyone else did the same sort of control-T hack, they likely invented it independently. Norman Wilson Toronto ON

6 years, 11 months

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Re: [TUHS] History of top

by jnc＠mercury.lcs.mit.edu

> From: Clem Cole > Tops-20 or TENEX (aka Twin-Ex). ISTR the nickname we used was 'TWENEX'? BTW, the first 20 at MIT (MIT-XX) had a 'Dos Equis' label prominently stuck to it... :-) Noel

6 years, 11 months

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Re: [TUHS] Control-T (was top)

by jnc＠mercury.lcs.mit.edu

> From: Dave Horsfall > I have a clear recollection that UNSW's driver (or was it Basser?) did > not use interrupts .. but used the clock interrupt to empty the silos > every so often. I'd check the source in the Unix Archive, but I don't > remember which disk image it's in ... Can anyone confirm or deny this? I found this one: https://minnie.tuhs.org//cgi-bin/utree.pl?file=AUSAM/sys/dmr/dz.c which seems to be the one you're rhinking of, or close to it. It actually does use interrupts, on both sides - sort of. On the input side, it uses the 'silo alarm', which interrupts when the input buffer has 16 characters in it. This has the same issue as the silo on the DH11 - if there are less characters than that waiting, the host never gets an interrupt. Which may be why it does the timer-based input check also? The output side is entirely interrupt driven; it _does_ reduce the number of interrupts by checking _every_ output line (on every DZ11 in the machine) to see if that line's ready for a character when it gets any output interrupt, which will definitely seriously reduce the number of output interrupts - but even then, if _one_ line is going flat out, that's still 1000 interrupts per second. Noel

6 years, 11 months

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Re: [TUHS] History of top

by Norman Wilson

Arthur Krewat: On 5/29/2018 4:11 PM, Dan Cross wrote: > "I don't always use computers, but when I do, I prefer PDP-10s." > > B B B B - Dan C. Write-in for President in 2020. === Only if he's Not Insane. Norman Wilson Toronto ON

6 years, 11 months

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Re: [TUHS] DZ11s (was Control-T (was top))

by Norman Wilson

Long ago, at Caltech, I ran a VAX which had a mix of DZ11s and Able DH/DMs. The latter were indeed much more pleasant, both because of their DMA output and their fuller modem control. For the DZ11s we used a scheme that originated somewhere in the USG-UNIX world: output was handled through a KMC11. Output interrupts were disablled on the DZ; a program running in the KMC fetched output data with DMA, then spoon-fed it into the DZ, polling the status register to see when it was OK to send more, then sending an interrupt to the host when the entire data block had been sent. The KMC, for those fortunate enough not to have programmed it, has a very simple processor sort of on the level of microcode. It has a few specialized registers and a simple instruction set which I don't think had all four of the usual arithmetic ops. I had to debug the KMC program so I had to learn about it. When I moved to Bell Labs a few years later, we didn't need the KMC to drive serial lines--Dennis's stream I/O code was able to do that smoothly enough, even with DZ11s on a VAX-11/750 (and without any assembly-language help either!). But my experience with the KMC was useful anyway: we used them as protocol-offload processors for Datakit, and that code needed occasional debugging and tweaking too. Bill Marshall had looked after that stuff in the past, but was happy to have someone else who wasn't scared of it. Norman Wilson Toronto ON

6 years, 11 months

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Re: [TUHS] Control-T (was top)

by jnc＠mercury.lcs.mit.edu

> From: Paul Winalski > DZ11s ... the controller had no buffer Huh? The DZ11 did have an input buffer. (See the 'terminals and communications handbook', 1978-79 edition, page 2-238: "As each character is received ... the data bits are placed ... in a .. 64-word deep first-in/first-out hardware buffer, called a 'silo'.") Or did you mean output: > if you were doing timesharing it could bring the CPU to its knees in > short order The thing that killed an OS was the fact that output was programmed I/O, a character at a time; using interrupt-driven operation, it took an interrupt per character. So for a 9600 baud line, 9 bits/character (1 start + 7 data + 1 stop - depending on the line configuration), that's about 1000 characters per second -> 1000 interrupts per second. The DH11 used DMA for output, and was much easier on the machine. Noel

6 years, 11 months

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Re: [TUHS] History of top

by Nelson H. F. Beebe

Lars Brinkhoff <lars(a)nocrew.org> reports on Mon, 28 May 2018 10:31:56 +0000: >> But apparently the inspiration came from VMS: >> http://web.archive.org/web/20170527120123/http://www.unixtop.org:80/about.s… That link contains the statement >> The first version of top was completed in the early part of 1984. However, on TOPS-20, which was developed several years before VMS, but still from the same corporation, we had the sysdpy utility which produced a similar display as top does. >From my source archives, I find in score/4-utilities/sysdpy.mac the ending comments: ;462 - DON'T DO A RLJFN AFTER A CLOSF IN NEWDPY ;<4.UTILITIES>SYSDPY.MAC.58, 2-Jun-79 14:15:54, EDIT BY DBELL ;461 - START USING STANDARD TOPS-20 EDIT HISTORY CONVENTIONS, AND ; REMOVE OLD EDIT HISTORY. ... ;COPYRIGHT (C) 1976,1977,1978,1979 BY DIGITAL EQUIPMENT \ CORPORATION, MAYNARD, MASS. I therefore expect that there was 460-entry list of log messages that predated 2-Jun-1979, and likely went back a few years. Two other versions of sysdpy.mac in my archives have also dropped log messages before 461. Even before TOPS-20, on the CDC 6400 SCOPE operating system, there was a similar tool (whose name I no longer recall) that gave a continuously updated display of system-wide process activity. That was available in at least late 1973. I suspect that top-like displays were added to most other interactive operating systems, as soon as screen terminals made updates convenient without wasting console paper. One of the first questions likely to be asked by interactive users is "what is my job doing?". In a TOPS-20 terminal window, you could type Ctl-T to get a one-line status report for the job that was currently running from your terminal. For many users, that was preferable to sysdpy, and it was heavily used. ------------------------------------------------------------------------------- - Nelson H. F. Beebe Tel: +1 801 581 5254 - - University of Utah FAX: +1 801 581 4148 - - Department of Mathematics, 110 LCB Internet e-mail: beebe(a)math.utah.edu - - 155 S 1400 E RM 233 beebe(a)acm.org beebe(a)computer.org - - Salt Lake City, UT 84112-0090, USA URL: http://www.math.utah.edu/~beebe/ - -------------------------------------------------------------------------------

6 years, 11 months

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Re: [TUHS] History of top

by jnc＠mercury.lcs.mit.edu

> From: Lars Brinkhoff > I'm surprised it appeared that late. Were there any other versions or > similar Unix programs before that? The MIT ~PWB1 system had a thing called 'dpy', I think written at MIT based on 'ps' (and no doubt inspired by ITS' PEEK), which had similar functionality. Seems like it never escaped, though. Man page and source here: http://ana-3.lcs.mit.edu/~jnc/tech/unix/man1/dpy.1 http://ana-3.lcs.mit.edu/~jnc/tech/unix/s1/dpy.c The top of my hard-copy man page says 'November 1977', but I suspect it dates back further than that. Noel

6 years, 12 months

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Alan Turing and his computable numbers

by Dave Horsfall

On this day in 1936, notable mathematician Alan Turing submitted his thesis "On Computable Numbers", thereby laying the foundations for today's computers. Sigh; if only he hadn't eaten that apple... And we'll never know whether it was murder or suicide. -- Dave

6 years, 12 months

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Re: [TUHS] Who used *ROFF?

by Doug McIlroy

> I still find pic really useful ... > I don't know of any other tool that lets you do drawings like that Unix had "ideal", a remarkable language by Chris Van Wyk, based on complex numbers and capable of some constraint solving. Its code seemed to be lost but can now be found in one of the online v10 repositories. I've been meaning to try to resurrect it. If anyone has already done so, I'd love to hear about it. I, too, have some pic macros, though no big coherent packages, to do things like polar coordinates and solving for the intersection of lines and circles. I have even in extremis made filled triangles with scripts that massage PostScript by deleting corners of filled rectangles. Then from triangles you can, with patience, make polygons. Doug

6 years, 12 months

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Fwd: unix

by John P. Linderman

A worthy question. ---------- Forwarded message ---------- From: Richard Haight <dickhaight(a)gmail.com> Date: Thu, May 24, 2018 at 2:53 PM Subject: unix To: jpl.jpl(a)gmail.com Recently I was asked if I still had a spare deck of the Unix-25 cards. Hadn’t thought of them in years. But it made me realize that 2019 will be the 50th. Is anyone working on something to mark the anniversary?

6 years, 12 months

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History of top

by Lars Brinkhoff

Hello, I'm curious about the history of "top". As far as I can see, the first version was written by William LeFebvre and posted to net.sources in 1984. I'm surprised it appeared that late. Were there any other versions or similar Unix programs before that? Best regards, Lars Brinkhoff

6 years, 12 months

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Fwd: Old Unix manuals, TMs, etc

by Warren Toomey

All, I've just received the following e-mail. I am not able to physically get these documents, but if you are interested in them, feel free to contact Mel yourself. Cheers, Warren ----- Forwarded message from meljmel-unix(a)yahoo.com ----- Date: Wed, 23 May 2018 13:30:09 +1000 (AEST) From: meljmel-unix(a)yahoo.com To: Warren T <wkt(a)tuhs.org> Subject: Old Unix manuals, TMs, etc Hi, I started working at Bell Labs in 1971 and although not in the computing science research department, I was in another department down the hall. As a result I have many old Unix manuals, TM's and other papers that I wish to dispose of. I found you when I did a search to see if there was anyone who might want them. Appended below is a list of what I have. If you are interested in any of it or know who else might be, please let me know. If I can't find anyone to take them I guess I'll just throw them out. Mel meljmel-unix(a)yahoo.com ========== These are the old Unix Manuals I have: UNIX PROGRAMMER'S MANUAL Program Generic PG-1C300 Issue 2 Published by the UNIX Support Group January, 1976 UNIX PROGRAMMER'S MANUAL Program Generic PG-1C300 Issue 3 Published by the UNIX Support Group March, 1977 UNIX User's Manual Release 3.0 T.A. Dolotta S. B. Olsson A.G. Petrucceli Editors June 1980 Laboratory 364 Bell Telephone Laboratories, Incorporated Murray Hill, NJ 07974 The C Programmer's Handbook AT&T Bell Laboratories February 1984 M. I. Bolsky P. G. Matthews System Training Center Copyright 1984 Piscataway, New Jersey 08854 Unix System V Quick Reference Guide Copyright 1985 AT&T Technologies, Inc 307-130 UNIX TIME-SHARING SYSTEM PROGRAMMER'S MANUAL Research Version Ninth Edition, Volume 1 September, 1986 AT&T Bell Laboratories Murray Hill, New Jersey The Vi User's Handbook by Morris I. Bolsky Systems Training Center Copyright 1984 AT&T Bell Laboratories Incorporated Copyright 1985 AT&T Technologies, Inc Unix Research System Programmer's Manual Tenth Edition, Volume I Computing Science Research Center Murray Hill, New Jersey 1990, American Telephone and Telegraph Company Bell Laboratories Division ISBN 0-03-047532-5 A. G. Hume M. D. McIlroy October, 1989 Unix Research System Papers Tenth Edition, Volume II Computing Science Research Center AT&T Bell Laboratories Murray Hill, New Jersey 1990, American Telephone and Telegraph Company Bell Laboratories Division ISBN 0-03-047529-5 A. G. Hume M. D. McIlroy January, 1990 ---------- These are old Unix Technical Memorandum and Papers I have: The C Reference Manual January 15, 1974 TM: 74-1273-1 D. M. Ritchie Programming in LIL: A Tutorial June 17, 1974 TM: 74-1352-6 LIL Reference Manual June 19, 1974 TM: 74-1352-8 A Description of the UNIX File System September 16, 1975 Author J. F. Maranzano The Portable C Library May 16, 1975 TM: 75-1274-11 Author: M. E. Lesk Lex - A Lexical Analyzer Generator July 21, 1975 TM: 75-1274-15 Author: M. E. Lesk Introduction to Scheduling and Switching under UNIX October 20, 1975 TM: 75-8234-7 Author: T. M. Raleigh Make - A program for Maintaining Computer Programs December 5, 1975 TM: 75-1274-26 Author: S. I. Feldman UNIX Programming Brian w. Kernighan Denis M. Ritchie ? 1975 ? Bell Laboratories, Murray Hill, New Jersey 07974 "This paper is an introduction to programming on Unix. The emphasis is on how to write programs that interface to the operating system." The C Language Calling Sequence September 26, 1977 TMs: 77-1273-15, 77-1274-13 Authors: A.C. Johnson, D.M. Ritchie, M.E. Lesk Lint, a C Program Checker September 16, 1977 TM: 77-1273-14 Author: S. C. Johnson The M4 Macor Processor April 1, 1977 TM: 77-1273-6 Authors: Brian W. Kernighan, Dennis M. Ritchie C Reference Manual Dennis M. Ritchie May 1, 1977 Murray Hill, New Jersey 07974 C Language Portability September 22, 1977 Author: B. A. Tague Variable Length Argument Lists in C June 12, 1978 Author: Andrew Koenig An Introduction to the UNIX Shell July 21, 1978 TM: 78-1274-4 Author: S.R. Bourne SED - A Non-Interactive Text Editor August 15, 1978 TM: 78-1270-1 Author: Lee E. McMahon UNIX Shell Tutorial July 14, 1981 TM: 81-59322-5 Author: J. R. Mashey Awk - A pattern Scanning and Processing Language Programmer's Manual June 19, 1985 Authors: Alfred V. Aho, Brian W. Kernighan, Peter J. Weinberger TMs: 11272-850619-06TM, 11276-850619-09TM, 11273-850619-03TM Yacc: Yet Another Compiler-Compiler July 31. 1978 TM: 78-1273-4 Author: Stephen C. Johnson RATFOR - A Preprocessor for a Rational Fortran October 22, 1976 TM: 76-1273-10 Author Brian W. Kernighan Miscellaneous undated (but old) papers: On the Security of UNIX Dennis M. Ritchie A New Input-Output Package D. M. Ritchie The Unix I/O System Dennis M. Ritchie Programming in C - A tutorial Brian W. Kernighan ? Date ? ========== ----- End forwarded message -----

7 years

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Obsolesence guaranteed

by Dave Horsfall

WHo'll be the first to run our favourite OS with one of these? http://obsolescence.wixsite.com/obsolescence/pidp-11-technical-details ``From a hardware perspective, the PiDP is just a frontpanel for a Raspberry PI. In the hardware section below, the technical details of the front panel are explained. In fact, the front panel could just as easily be driven by any microcontroller (or FPGA), it only lights the leds and scans the switch positions.'' -- Dave

7 years

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Genealogy of PDP-11 Unix

by Warren Toomey

I had an e-mail from someone who said: PDP-11 Sys V is apparently derived from Unix CB 3.0, not from the normal route... Or so says the great interweb :) I found a family tree that suggests this. Know anything about this? I hadn't heard of this before, can anybody substantiate or negate this assertion, or shed more light on the genealogy od PDP-11 System V? Thanks, Warren

7 years

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Obsolescence Guaranteed (fwd)

by Dave Horsfall

Might be of interest to the denizens here... -- Dave ---------- Forwarded message ---------- Date: Sun, 20 May 2018 17:56:39 +1000 From: Richard To: Dave Subject: Obsolescence Guaranteed The things people are doing with Raspberry Pis these days… http://obsolescence.wixsite.com/obsolescence/pidp-11-technical-details of it an ‘8 is more to your taste… http://obsolescence.wixsite.com/obsolescence/pidp-8 Cheers, Richard

7 years

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Who used *ROFF?

by Nemo

I have read that one of the first groups in AT&T to use early Unix was the legal dep't, specifically to use *roff to write patent applications. Can anyone elaborate on this or supply references? (This would in great contrast to today, where most applications are written with certain products despite the USPTO, EPO, and others only accepting PDF versions.) It would also be interesting to learn how the writers were taught *roff, what editors were used, and what they thought. (I recall that the secretaries, as they were then called, in the math dep't used vi to compose plain TeX documents and xdvi to proofread them.) N.

7 years

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Re: [TUHS] PWB - what is the history?

by Rudi Blom

>Date: Wed, 16 May 2018 10:05:24 -0400 >From: Doug McIlroy <doug(a)cs.dartmouth.edu> >To: tuhs(a)minnie.tuhs.org >Cc: lorinda.cherry(a)gmail.com >Subject: Re: [TUHS] PWB - what is the history? >Message-ID: <201805161405.w4GE5OeJ012025(a)coolidge.cs.Dartmouth.EDU> >Content-Type: text/plain; charset=us-ascii > <snip> >They were in WWB (writers workbench) not PWB (programmers workbench). >WWB was a suite of Unix programs, organized by Nina MacDonald of USG. >It appeared in various Unix versions, including research v8-v10. > >Lorinda Cherry in research wrote most of the basic tools in WWB, ... I see Ms. Cherry also has a wiki page https://en.wikipedia.org/wiki/Lorinda_Cherry which has "Cherry raced rally cars as a hobby". and the page contains a link to an interesting document which brings us back to the PWB "A Research UNIX Reader: Annotated Excerpts from the Programmer’s Manual, 1971-1986 M. Douglas McIlroy" - uncle rubl

7 years

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Re: [TUHS] PWB - what is the history?

by Doug McIlroy

> I think you mean 'style' and 'diction'. I thought those came from research? I > remember seeing papers about them in a manual; maybe 7th Ed or 4.2/4.3BSD? They were in WWB (writers workbench) not PWB (programmers workbench). WWB was a suite of Unix programs, organized by Nina MacDonald of USG. It appeared in various Unix versions, including research v8-v10. Lorinda Cherry in research wrote most of the basic tools in WWB, most notably style, diction, and the really cool "parts" that underlay style. William Vesterman at Rutgers suggested style and diction. Having parts up her sleeve, Lorinda was able to turn them out almost overnight. Most anyone else would scarcely have known how to begin to make style. Just yesterday Lorinda received a Pioneer in Tech award from the National Center for Women in IT. Parts and eqn, both initiated by her, certainly justify that honor. [Parts did a remarkable job of tagging text with parts of speech, without getting bogged down in the swamp of parsing English. It was largely implemented in sed--certainly one of the grander programs written in that language. Style reported statistics like length of words, frequency of adjectives, and variety of sentence structure. Diction flagged cliches and other common infelicities. WWB offered advice based on the findings of these and other text-analysis programs.] Doug

7 years

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Re: [TUHS] Who used *ROFF?

by Doug McIlroy

> Wouldn't the -man macros have predated -ms? Indeed. My error. The original -man package was quite weak. It got a major face lift for v7 and once more at v9 or so. And further man-page packages are still duking it out today. -ms has lots of rivals, too, but its continued popularity attests to Mike Lesk's fine sense of design. Doug

7 years

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Re: [TUHS] Who used *ROFF?

by jnc＠mercury.lcs.mit.edu

> From: Nemo > I have read that one of the first groups in AT&T to use early Unix was > the legal dep't, specifically to use *roff to write patent applications. > Can anyone elaborate on this or supply references? Are you familiar with the description in Dennis M. Ritchie, "The Evolution of the Unix Time-sharing System": https://www.bell-labs.com/usr/dmr/www/hist.htm (in the section "The first PDP-11 system")? Not a great deal of detail, but... > It would also be interesting to learn how the writers were taught *roff, > what editors were used I'm pretty sure 'ed' was the only editor available at that point. Noel

7 years

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Re: [TUHS] PWB - what is the history?

by jnc＠mercury.lcs.mit.edu

> From: Clem Cole > Programmer's Workbench - aka PWB was John Mashey and team in Whippany. > They took a V6 system and make some changes I was suprised to find, reading the article on it in the Unix BSTJ issue, that the system changes were less than I'd thought. Some of the stuff in the PWB1 release that we have (see previous message) is _not_ described in that article (which is fairly detailed), which further compounds the lack of clarity over who/what/when between V6 and V7. > Noel may know how it made it to MIT That I _do_ know! There was some sort of Boy Scouts group at Bell (not sure exactly where) and one of the members went to MIT. I think he was doing undergraduate research work in the first group at MIT to have Unix (Steve Ward's), but anyway he had some connection there; and I think also had a summer job at Bell. He was the Bell->MIT conduit. > PWB 2.0 was released a few years later and was based on the UNIX/TS > kernel and some other changes and it was around this time that the UNIX > Support Group was formed ??? If PWB1 was in July '77, and PWB2 was some years later, USG couldn't have been formed 'around [that] time' because there's that USG document from January '76? Noel

7 years

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Re: [TUHS] PWB - what is the history?

by jnc＠mercury.lcs.mit.edu

> From: Jon Forrest <nobozo(a)gmail.com> > John Mashey had a lot to do with PWB so maybe he can say a few words > about it if he's on here. It would be great to have some inside info about the relationship among the Research, USG and PWB systems. Clearly there was comunication, and things got passed around, but we know so little about what was happening during the period between V6 and V7 when a lot happened (e.g. the changes to C, just mentioned). E.g. check out the PWB1 version of exec(): https://minnie.tuhs.org//cgi-bin/utree.pl?file=PWB1/sys/sys/os/sys1.c It's been changed from V6 to copy the arguments into swap space, _not_ buffers allocated from the system buffer pool (which is how V6 does it). So, who did this originally - did the PWB people do it, or was it something the research people did, that PWB picked up? I used to think it was USG, but there's a 'Unix Program Description' document prepared by USG, dated January 1976, and it's still clearly using the V6 approach. The PWB1 release was allegedly July, 1977: https://minnie.tuhs.org//cgi-bin/utree.pl?file=PWB1 (Which is, AFAIK, the _only_ set of sources we have for after V6 and before V6 - other than the MIT system, which seems to be basically PWB1.) So who did the exec() changes, originally? And I could list a bunch more like this... Noel

7 years

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Good ol' ed (Was *ROFF)

by Ron Natalie

I never really learned VI. I can stumbled through it in ex mode if I have to. If there's no EMACS on the UNIX system I'm using, I use ed. You get real good at regular expressions. Some of my employees were pretty amazed at how fast I could make code changes with just ed.

7 years

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Re: [TUHS] Who used *ROFF?

by Doug McIlroy

Here's part of the story. > From: "Doug McIlroy" <doug(a)cs.dartmouth.edu> > To:<tuhs(a)minnie.tuhs.org> > Sent:Fri, 16 Dec 2016 21:09:16 -0500 > Subject:[TUHS] How Unix made it to the top > > It has often been told how the Bell Labs law department became the > first non-research department to use Unix, displacing a newly acquired > stand-alone word-processing system that fell short of the department's > hopes because it couldn't number the lines on patent applications, > as USPTO required. When Joe Ossanna heard of this, he told them about > nroff and promised to give it line-numbering capability the next day. > They tried it and were hooked. Patent secretaries became remote > members of the fellowship of the Unix lab. In due time the law > department got its own machine. Come to think of it, they must already have had a machine, probably leased from the commercial word-processing company, for they had DEC tapes they needed to convert to Unix format. Several of us in the Unix lab spent a memorable afternoon decoding the proprietary format. It was finally broken when we computed a bitwise autocorrelation function. It had a big peak at seven. The tapes were pure ASCII rather than bytewise ASCII--a lot of work for very little data compression. As for training, the secretaries had to learn nroff and ed plus the usual lot of ls, mkdir, mv, cp, rm. The patent department had to invest in modems and order phone lines to plug them into. I don't know what terminals they used. >From this distant point in time it seems that it all happened in a couple of weeks. Joe Ossanna did most of the teaching, and no doubt supplied samples to copy. As far as I know the only other instructional materials would have been man pages and the nroff manual (forbiddingly terse, though thorough). He may have made a patent-macro package, but I doubt it; I think honor for the first real macro package goes to Lesk's -ms. Doug

7 years

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Thoughts on UNIX Licensing vs UNIX Technology

by Clem Cole

Larry’s question about PWB made me think it might be useful to this list for some of this to be written down. When you write the story of UNIX, licensing is a huge part of it (both good and bad). As I have tried to explain before the 1956 consent decree and the later 1980 Judge Green ruling, as well as how the AT&T legal department set up the licenses really cast huge shadows that almost seem trite today; but seem to have been forgotten. In fact later licensing would become so important, one of the more infamous UNIX wars was based on it (if you go back to the original OSF Founding Principles – two of them are ‘Fair and Stable Licensing Terms’). As we all know, because of the original 1956 decree, AT&T was not allowed to be in the computer business and so when people came calling both to use it (Academically and Commercially) and to relicense it; history has shown that AT&T’s management killed the golden goose. I’d love to hear the views of Doug, Steve, Ken and other who were inside looking out. FWIW: These are my thoughts from an Academic and Commercial user back in the day. AT&T’s management was clearly concerned about the consent decree and the original licenses show it. UNIX was licensed for free to academic institutions for research use (sans a small tape copying fee) and the bits were ‘abandoned on your door step.’ This style of license, along with the publishing of the ideas behind really did get the ideas out and the academic community loved it. We used it and we were able to share everything. The academic license was fine until people want to start to use in a commercial setting (Rand Corp). Again, AT&T legal is worried about being perceived in the computer business, so the original commercial use license shows it. AT&T licensing basically uses the academic license but add the ability to actually use it for commercial purposes. Then the first Universities start to want to use UNIX more like a commercial system [Dan Klein and I would go on strike and force CMU to purchase first commercial use license for an Academic setting, following by Case Western]. As AT&T management realized the UNIX IP did seem to be some value, just like the transistor had been earlier, it seems like they wanted to find a way to keep it under their control. I remember having a dinner conversation with Dennis at a USENIX about this topic. Steve has expressed they told many folks to treated it as a ‘trade secret’ (which is strange to me since the cat as already out of the bag by then and the ideas (IP) behind UNIX had already been extensively published (we even had USENIX formed to discuss ideas). By the time Judge Green allows AT&T to be in the computer business I think AT&T management completely misunderstood the value of what they had. The AT&T legal team had changed the commercial rules in every new UNIX release a new license was created, and thus firms like DEC, HP, IBM *et al* were getting annoyed because they had begun to invest in the technology themselves and the feeling inside of those firms was that AT&T management was changing the ground rules after the game started. IMO a funny thing happened (bad karma), it seems like the tighter AT&T management seems to try to control things in the UNIX community, the less control the community gave them. Clearly, the new features of the technology started to be driven by BSD. But the license was the one place they could control and they tried. In fact, by the time of the SVR4 it all came to a head and OSF was formed because most firms were unwilling to give AT&T the kind of control they were asking in the that license [as Larry has previously expressed, Sun made a Faustian deal WRT to SVR4]. In the end, the others were shipping from an SVR3 license or had bought it out.

7 years

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Re: [TUHS] Who used *ROFF?

by jnc＠mercury.lcs.mit.edu

> From: Ralph Corderoy <ralph(a)inputplus.co.uk> >> This is also were typesetter C comes from. > What's that? An evolution of C past the fairly early version in V6, but prior to V7. Reputedly the name comes from extensions done for doing troff. See: http://ana-3.lcs.mit.edu/~jnc/history/unix/CChanges.txt http://ana-3.lcs.mit.edu/~jnc/history/unix/COChanges.txt for some historical documentation. Noel

7 years

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Re: [TUHS] Who used *ROFF?

by jnc＠mercury.lcs.mit.edu

> From: Clem cole > Thinking about this typesetter C may have been later with ditroff. Not so sure about that; we had that C at MIT, but only regular troff (which had been hacked to drive a Varian). > From: Arnold Skeeve > It seems to be shortly after the '78 release of V7. No, typesetter C definitely pre-dated V7. The 'PWB1' system at MIT had the new C. Looking at the documentation files for the extension (e.g. addition of 'long's), none of them have dates in them (alas), but my hard-copy printout of one is dated "May 8 1978", and it was several years old at that point. (Also, several sources give '79 for V7 - Salus says 'June 1979'). Noel

7 years

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Re: [TUHS] The birth of the Z3

by jnc＠mercury.lcs.mit.edu

> From: Clem Cole > Their is a open question about the need to support self modifying code > too. I personally don't think of that as important as the need for > conditional instructions which I do think need to be there before you > can really call it a computer. Here's one way to look at it: with conditional branching, one can always write a program to _emulate_ a machine with self-modifying code (if that's what floats your boat, computing-wise) - because that's exactly what older, simple microcoded machines (which don't, of course, have self-modifying code - their programs are in ROM) do. Noel

7 years

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The birth of the Z3

by Dave Horsfall

Way back on this day in 1941, Conrad Zuse unveiled the Z3; it was the first programmable automatic computer as we know it (Colossus 1 was not general-purpose). The last news I heard about the Z3 was that she was destroyed in an air-raid... This pretty much started computing, as we know it. -- Dave

7 years

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Latest IOCCC Entry: PDP-7 and PDP-11 emulator

by Warren Toomey

All, in case you haven't seen it: https://www.ioccc.org/2018/mills/ This is a PDP-7 emulator in C, enough to run PDP-7 Unix. But the author has written a PDP-11 emulator in PDP-7 assembly, and uses this to run 2.9BSD on the emulated PDP-7 :-) Cheers, Warren

7 years

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Re: [TUHS] Who used *ROFF?

by Rudi Blom

>From: jnc(a)mercury.lcs.mit.edu (Noel Chiappa) >To: tuhs(a)tuhs.org >Cc: jnc(a)mercury.lcs.mit.edu >Subject: Re: [TUHS] Who used *ROFF? >Message-ID: <20180512110127.0B81418C08E(a)mercury.lcs.mit.edu> > <snip> >Are you familiar with the description in Dennis M. Ritchie, "The Evolution of >the Unix Time-sharing System": > > https://www.bell-labs.com/usr/dmr/www/hist.htm > <snip> Please note the URL should end with ".html", not ".htm" I wasted 5 minutes (insert big grin) wondering why I got an 404 like 404 Not Found Code: NoSuchKey Message: The specified key does not exist. Key: hist.htm RequestId: 454E36190753F99C HostId: 6EJTsEdvnbnAr4VO7+mxSWH+dcX8X6AGRLZxwOLha/9q5G2CAxsVbEw6aMF+NHIPbhrAQ+/t/8o=

7 years

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Re: [TUHS] Windows Notepad to support Unix line endings

by Rudi Blom

Hardly ever use notepad, hardly ever used notepad. Especially since I discovered notepad++ many years ago ( https://notepad-plus-plus.org ) Of course, I use what is handy for what I'm doing. 'vim' I use when I want to do some 'manipulation :-)

7 years

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UUCP "bag" files

by Grant Taylor

Does anyone know why UUCP "bag" files are called "bag"? Seeing as this relates to unix-to-unix-copy, I figured that someone on TUHS might have an idea. Thanks in advance. -- Grant. . . . unix || die

7 years

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Resurrecting a PDP11

by Robert Diamond

Just thought I’d share a quick video - some folks in my office got a PDP11/34 up running Adventure under RT-11 today. https://www.youtube.com/watch?v=U_jB23UqgCY <https://www.youtube.com/watch?v=U_jB23UqgCY> (Sorry for vertical orientation and non-Unix-related content) --- Robert Diamond rob(a)robdiamond.com

7 years

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Z3 from 1941

by Mike Markowski

Tomorrow, May 12, in 1941 the Z3 computer was presented by Konrad Zuse: https://en.wikipedia.org/wiki/Z3_(computer) I enjoyed reading the specs at the bottom of the Wikipedia page. I never heard of this project until today, coming across it an article. Mike Markowski

7 years

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Windows Notepad to support Unix line endings

by Robert Diamond

30+ years later… https://blogs.msdn.microsoft.com/commandline/2018/05/08/extended-eol-in-not… <https://blogs.msdn.microsoft.com/commandline/2018/05/08/extended-eol-in-not…> --- Robert Diamond rob(a)robdiamond.com

7 years

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Happy birthday, Edsger Dijkstra!

by Dave Horsfall

Born on this day in 1930, he gave us ALGOL, the basis of all decent programming languages today, and the entire concept of structured programming. Ah, well I remember the ALGOLW compiler on the 360... There's a beaut article here: https://www.cs.utexas.edu/users/EWD/ewd02xx/EWD215.PDF And remember, testing can show the presence of errors, but not their absence... -- Dave Horsfall BSc DTM (VK2KFU) -- FuglySoft -- Gosford IT -- Unix/C/Perl (AbW) People who fail to / understand security / surely will suffer. (tks: RichardM)

7 years

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I'm interested in the thoughts of the TUHS folks about this

by Clem Cole

I'm curious as UNIX folks if somewhere can enlighten me. I sometimes answer things on Quora and a few years ago the following question was posted: What does "Experience working in Unix/Linux environments" mean when given as a required skill in company interviews? What do they want from us? <https://www.quora.com/What-does-Experience-working-in-Unix-Linux-environmen…> Why would this be considered a spam violation - which I was notified today as being so. It all depends the job for the specific experiences the hiring mangers want to see. The #1 thing I believe they will looking for is something that does not need to have a GUI to be useful. If you a simple user, it means you are comfortable in a text based, shell environment and are at least familiar with, if not proficient with the UNIX tools such as, ed, vi or emacs, grep, tail, head, sed, awk, cut, join, tr, etc. You should be able to use one or more of the Bourne Shell/Korn Shell/Bash family or CShell. You should be familiar with the UNIX file tree and basic layout and its protection scheme. It helps if you understand the differences between BSD, SysV, Mac OSx, and Linux layout; but for many jobs in the UNIX community that may not be required. You should also understand how to use the Unix man command to get information on the tools you are using —* i.e.* you should have read, if not own a copy of Kernighan and Pike The Unix Programming Environment (Prentice-Hall Software Series): Brian W. Kernighan, Rob Pike: 9780139376818: Amazon.com: Books <https://www.amazon.com/Unix-Programming-Environment-Prentice-Hall-Software/…> and be proficient in the first four chapters. If the job requires you writing scripts to be able to write Shell script (*i.e.* program the shell) using the Bourne Shell syntax *i.e.* Chapter 5 (Shell Programming). If you are a programmer, then you need to be used to using the UNIX/Linux toolchains and probably not require an IDE - again as a programmer knowledge if not our proficiency of at least source code control system from SCCS, RCS, CVS, SVN, Mercurial, git or the like needed. Kernighan and Pike’s Chapter’s 6–8 should be common knowledge. But to be honest, you also should be familiar with the contents contained within it, if not own and keep a copy of the Rich Steven’s Advanced Programming in the UNIX Environment, 3rd Edition: W. Richard Stevens, Stephen A. Rago: 9780321637734: Amazon.com: Books <https://www.amazon.com/Advanced-Programming-UNIX-Environment-3rd/dp/0321637…> (*aka* APUE) on your desk. If you are system administrator, then the required set of tools get much larger and besides the different way to “generate” (build) a system is a good idea; but less tools for user maintenance. In this case you should be familiar with, again if not own have a copy on your desk of Evi Nemeth’s Amazon.com: UNIX and Linux System Administration Handbook, 4th Edition (8580001058917): Evi Nemeth, Garth Snyder, Trent R. Hein, Ben Whaley: Books <https://www.amazon.com/UNIX-Linux-System-Administration-Handbook/dp/0131480…> - which is and has been one of if not the best UNIX admin work for many, many years. Updated 05/07/18: to explain I am not shilling for anyone. I am trying to honestly answer the question and make helpful recommendations of how to learn what the person asked to help them be better equipped to be employed in the Unix world. I used Amazon’s URL’s because they are global and easy to use as a reference. But I am not suggesting you purchase from them. In fact, if you can borrow a copy from you library to start, that might be a good idea.

7 years

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Re: [TUHS] Windows Notepad to support Unix line endings

by norman＠oclsc.org

Grant Taylor: (Maybe the 3' pipe wrench has something to do with it.) ======= Real pipes don't need wrenches. Maybe those in Windows do. Norman Wilson Toronto ON

7 years

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Old Usenet newsreader source code?

by Seth Morabito

Hi all, Forgive this cross-post from cctalk, if you're seeing this message twice. TUHS seems like a very appropriate list for this question. I'm experimenting with setting up UUCP and Usenet on a cluster of 3B2/400s, and I've quickly discovered that while it's trivial to find old source code for Usenet (B News and C News), it's virtually impossible to find source code for old news *readers*. I'm looking especially for nn, which was my go-to at the time. The oldest version I've found so far is nn 6.4, which is too big to compile on a 3B2/400. If I could get my hands on 6.1 or earlier, I think I'd have a good chance. I also found that trn 3.6 from 1994 works well enough, though it is fairly bloated. Earlier versions of that might be better. Does anyone have better Google-fu than I do? Or perhaps you've got earlier sources squirreled away? As an aside: If you were active on Usenet in 1989, what software were you using? -Seth -- Seth Morabito web(a)loomcom.com

7 years

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unix "awesome list"

by A. P. Garcia

Hi, There's a unix "awesome list". It mentions TUHS's wiki, as well as this quote: "This is the Unix philosophy: Write programs that do one thing and do it well. Write programs to work together. Write programs to handle text streams, because that is a universal interface." - Douglas McIlroy, former head of Bell Labs Computing Sciences Research Center https://github.com/sirredbeard/Awesome-UNIX

7 years

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Re: [TUHS] /dev/drum

by Johnny Billquist

On 08.05.18 04:00, jnc(a)mercury.lcs.mit.edu (Noel Chiappa) wrote: > > From: Johnny Billquist > > > My point being that ... pages are invisible to the process segments are > > very visible. And here we talk from a hardware point of view. > > So you're saying 'segmentation means instructions explicitly include segment > numbers, and the address space is a two-dimensional array', or 'segmentation > means pointers explicitly include segment numbers', or something like that? Not really. I'm trying to understand your argument. You said: "BTW, this reminds me of another key differentiator between paging and segments, which is that paging was originally _invisible_ to the user (except for setting the total size of the process), whereas segmentation is explicitly visible to the user." And then you used MERT as an example of this. My point then is, how is MERT any different from mmap() under Unix? Would you then say that the paging is visible under Unix, meaning that this is then segmentation? In my view, you are talking about a software concept. And as such, it has no bearing on whether a machine have pages or segments, as that is a hardware thing and distinction, while anything done as a service by the OS is a completely different, and independent question. > I'm more interested in the semantics that are provided, not bits in > instructions. Well, if we talk semantics instead of the hardware, then you can just say that any machine is segmented, and you can say that any machine is have pages. Because I can certainly make it appear both ways from the software point of view for applications running under an OS. And I can definitely do that on a PDP-11. The OS can force pages to always be 8K in size, and the OS can (as done by lots of OSes) provide a mechanism that gives you something you call segments. > It's true that with a large address space, one can sort of simulate > segmentation. To me, machines which explicitly have segment numbers in > instructions/pointers are one end of a spectrum of 'segmented machines', but > that's not a strict requirement. I'm more concerned about how they are used, > what the system/user gets. So, again. Where does mmap() put you then? And, just to point out the obvious, any machine with pages have a page table, and the page table entry is selected based on the high bits of the virtual address. Exactly the same as on the PDP-11. The only difference is the number of pages, and the fact that the page on the PDP-11 do not have a fixed length, but can be terminated earlier if wanted. So, pages are explicitly numbered in pointers on any machine with pages. > Similarly for paging - fixed sizes (or a small number of sizes) are part of > the definition, but I'm more interested in how it's used - for demand loading, > and to simplify main memory allocation purposes, etc. I don't get it. So, in which way are you still saying that a PDP-11 don't have pages? > >> the semantics available for - and_visible_ to - the user are > >> constrained by the mechanisms of the underlying hardware. > > > That is not the same thing as being visible. > > It doesn't meet the definition above ('segment numbers in > instructions/pointers'), no. But I don't accept that definition. I'm trying to find out what your definition is. :-) And if it is consistent and makes sense... :-) > > All of this is so similar to mmap() that we could in fact be having this > > exact discussion based on mmap() instead .. I don't see you claiming > > that every machine use a segmented model > > mmap() (and similar file->address space mapping mechanisms, which a bunch of > OS's have supported - TENEX/TOP-20, ITS, etc) are interesting, but to me, > orthagonal - although it clearly needs support from memory management hardware. Can you explain how mmap() is any different from the service provided by MERT? > And one can add 'sharing memory between two processes' here, too; very similar > _mechanisms_ to mmap(), but different goals. (Although I suppose two processes > could map the same area of a file, and that would give them IPC mapping.) That how a single copy of shared libraries happen under Unix. Exactly what happens if you modify the memory depends on what flags you give to mmap(). Johnny -- Johnny Billquist || "I'm on a bus || on a psychedelic trip email: bqt(a)softjar.se || Reading murder books pdp is alive! || tryin' to stay hip" - B. Idol

7 years

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Fun with early troff.

by Ron Natalie

I started with roff (the simplest but utterly frozen) and moved up to nroff. It was a few years later I was involved with a rather project to make a CAT phototypesetter emulator for the Versatec printer-plotter (similar to the BSD vcat, which we had not seen yet). My friend George Toth went to the Naval Research Laboratory and printed out the entire typeface on their CAT on transparent film. Then he set out to figure out a way to digitize it. Well, next door the the EE building (where the UNIX work took place at JHU) was the biophysics department. They had Scanning Transmission Electron Microscope there, quite an impressive machine. The front end of the thing was a PDP-11/20 with some digital to analog converters and vice versa and a frame buffer. The software would control the positioning of the beam and read back how much came through the material and was detected. Essentially, you were making a raster picture of the sample in the microscope. George comes up with this great idea. He takes a regular oscilloscope. He takes the deflection wires from the 11/20 off the microscope and puts them in the X and Y amplifiers of the scope. He then put a photomultiplier tube in the shell of an old scope camera. He'd cut out a single character and tape it the front of the scope and hang the camera on it. He'd fire up the microscope software and tell it to scan the sample. It would then put the image in the frame buffer. We'd pull the microscope RK05 pack out and boot miniunix and read the data from the frame buffer (why we didn't just write software to drive the A2D from miniunix I do not recall). Eventually, George gets everything scanned in and cleaned up. It worked somewhat adequately. Another amusing feature was that Michael John Muuss (my mentor) wrote a macro package tmac.jm. Some people were someone peeved that we now had a "nroff -mjm" option. Years later after ditroff was in vogue, my boss was always after me to switch to some modern document prep (Framemaker or the like). On one rough job I told him I'd do it but I didn't have time to learn framemaker. I write one page of this proposal, print it and then go on. My boss would proof it and then my coworker would come behind me and make the corrections. I ended up rewriting a million dollar (a lot of money back in 1989 or so) proposal in two days, complete with 25 pages of narrative and may be 50 pages of TBL-based tables showing compliance with the RFP. We won that contract and got several follow ons. Years later I was reading a published book. I noted little telltale bumps on the top of some of the tables. I wrote the author..."Did you use tbl and pic to typeset this book?" Sure enough he had. But it was way after I thought anybody was still using such technology. Of course, I was happy when Springer-Verlag suddenly learned out to typeset books. I had a number of their texts in college that didn't even look like the put a new ribbon in the typewriter when setting the book.

7 years

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Re: [TUHS] unix "awesome list"

by jnc＠mercury.lcs.mit.edu

> From: Clem Cole > I agree with Tannenbaum that uKernel's make more sense to me in the long > run - even if they do cost something in speed There's a certain irony in people complaining that ukernel's have more overhead - while at the same time time mindlessly, and almost universally, propogating such pinheaded computing hogs as '_mandating_ https for everything under the sun' (even things as utterly pointless to protect as looking at Wikipedia articles on mathematics), while simultaneously letting Amazon/Facebook/Google do the 'all your data are belong to us' number; the piling of Pelion upon Ossa in all the active content (page after page of JavaScript, etc) in many (most?) modern Web sites that does nothing more than 'eye candy'; etc, etc. Noel

7 years

5
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Re: [TUHS] [groff] Brian Kernighan on the evoution of eqn, pic, grap into troff

by Doug McIlroy

> https://en.wikipedia.org/wiki/TeX#Pronunciation_and_spelling Yes, TeX is supposed to be pronounced as Germans do Bach. And Knuth further recommends that the name be typeset as a logo with one letter off the base line. Damned if an awful lot of people, especially LaTeX users, don't follow his advice. I've known and admired Knuth for over 50 years, but part ways with him on this. If you use the ready-made LaTeX logo in running text, so should you also use flourished cursive for Coca-Cola and Ford; and back in the day, discordantly slanted letters for Holiday Inn. It's mad and it's a pox on the page. Doug

7 years

8
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Re: [TUHS] /dev/drum

by jnc＠mercury.lcs.mit.edu

> From: Johnny Billquist > My point being that ... pages are invisible to the process segments are > very visible. And here we talk from a hardware point of view. So you're saying 'segmentation means instructions explicitly include segment numbers, and the address space is a two-dimensional array', or 'segmentation means pointers explicitly include segment numbers', or something like that? I seem to recall machines where that wasn't so, but I don't have the time to look for them. Maybe the IBM System 38? The two 'spaces' in the KA10/KI10, although a degenerate case (fewer even than the PDP-11) are one example. I'm more interested in the semantics that are provided, not bits in instructions. It's true that with a large address space, one can sort of simulate segmentation. To me, machines which explicitly have segment numbers in instructions/pointers are one end of a spectrum of 'segmented machines', but that's not a strict requirement. I'm more concerned about how they are used, what the system/user gets. Similarly for paging - fixed sizes (or a small number of sizes) are part of the definition, but I'm more interested in how it's used - for demand loading, and to simplify main memory allocation purposes, etc. >> the semantics available for - and _visible_ to - the user are >> constrained by the mechanisms of the underlying hardware. > That is not the same thing as being visible. It doesn't meet the definition above ('segment numbers in instructions/pointers'), no. But I don't accept that definition. > All of this is so similar to mmap() that we could in fact be having this > exact discussion based on mmap() instead .. I don't see you claiming > that every machine use a segmented model mmap() (and similar file->address space mapping mechanisms, which a bunch of OS's have supported - TENEX/TOP-20, ITS, etc) are interesting, but to me, orthagonal - although it clearly needs support from memory management hardware. And one can add 'sharing memory between two processes' here, too; very similar _mechanisms_ to mmap(), but different goals. (Although I suppose two processes could map the same area of a file, and that would give them IPC mapping.) Noel

7 years

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Re: [TUHS] /dev/drum

by jnc＠mercury.lcs.mit.edu

> From: Johnny Billquist >> "A logical segment is a piece of contiguous memory, 32 to 32K 16-bit >> words long [which can grow in increments of 32 words]" > But then it is not actually giving programs direct access and > manipulation of the hardware. It is a software construct and service > offered by the OS, and the OS might fiddly around with various hardware > to give this service. I don't understand how this is significant: most time-sharing OS's don't give the users access to the memory management control hardware? > So the hardware is totally invisible after all. Not quite - the semantics available for - and _visible_ to - the user are constrained by the mechanisms of the underlying hardware. Consider a machine with a KT11-B - it could not provide support for very small segments, or be able to adjust the segment size with such small quanta. On the other side, the KT11-B could support starting a 'software segment' at any 512-byte boundary in the virtual address space, unlike the KT11-C which only supports 8KB boundaries. Noel

7 years

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Re: [TUHS] /dev/drum

by jnc＠mercury.lcs.mit.edu

> From: Johnny Billquist >> in MERT 'segments' (called that) were a basic system primitive, which >> users had access to. > the OS gives you some construct which can easily be mapped on to the > hardware. Right. "A logical segment is a piece of contiguous memory, 32 to 32K 16-bit words long ... Associated with each segment are an internal segment identifiern and an optional global name." So it's clear how that maps onto the PDP-11 memory management hardware - and a MERT 'segment' might use more than one 'chunk'. >> I understand your definitions, and like breaking things up into >> 'virtual addressing' (which I prefer as the term, see below), >> 'non-residence' or 'demand loaded', and 'paging' (breaking into >> smallish, equal-sized chunks), but the problem with using "virtual >> memory" as a term for the first is that to most people, that term >> already has a meaning - the combination of all three. Actually, after some research, it turns out to be only the first two. But I digress... > It's actually not my definition. Demand paging is a term that have been > used for this for the last 40 years, and is not something there is much > contention about. I wasn't talking about "demand paging", but rather your use of the term "virtual memory": >>> Virtual memory is just *virtual* memory. It's not "real" or physical >>> in the sense that it has a dedicated location in physical memory >>> ... Instead, each process has its own memory, which might be mapped >>> somewhere in physical memory, but it might also not be. And one >>> processes address 0 is not the same as another processes address >>> 0. They both have the illusion that they have the full memory address >>> range to them selves, unaware of the fact that there are many >>> processes who also have that same illusion. I _like_ having an explicit term for the _concept_ you're describing there; I just had a problem with the use of the _term_ "virtual memory" for it - since that term already has a different meaning to many people. Try Googling "virtual memory" and you turn up things like this: "compensate for physical memory shortages by temporarily transferring data from RAM to disk". Which is why I proposed calling it "virtual addressing" instead. > I must admit that I'm rather surprised if the term really is unknown to > you. No, of course I am familiar with "demand paging". Anyway, this conversation has been very helpful in clarifying my thinking about virtual memory/paging. I have updated the CHWiki article based on it: http://gunkies.org/wiki/Virtual_memory including the breakdown into three separate (but related) concepts: i) virtual addressing, ii) demand loading, and iii) paging. I'd be interested in any comments people have. > Which also begs the question - was there also a RK11-A? One assumes there much have been RK11-A's and -B's, otherwise they wouldn't have gotten to RK11-C... :-) I have no idea if both existed in physical form - one might have been just a design exercise). However, the photo of the non-RK11-C indicator panel confirms that at least one of them was actually implemented. > And the "chunks" on a PDP-11, running Unix, RSX or RSTS/E, or something > similar is also totally invisible. Right, but not under MERT - although there clearly a single 'software' segment might use more than one set of physical 'chunks'. Actuallly, Unix is _somewhat_ similar, in that processes always have separate stack and text/data 'areas' (they don't call them 'segments', as far as I could see) - and separate text and data 'areas' too, when pure code is in use; and any area might use more than one 'chunk'. The difference is that Unix doesn't support 'segments' as an OS primitive, the way MERT does. Noel

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Re: [TUHS] /dev/drum

by jnc＠mercury.lcs.mit.edu

> That would be a pretty ugly way to look at the world. 'Beauty is in the eye of the beholder', and all that! :-) > Not to mention that one segment silently slides over into the next one > if it's more than 8K. Again, precedent; IIRC, on the GE-645 Multics, segments were limited to 2^N-1 pages, precisely because otherwise incrementing an inter-segment pointer could march off the end of one, and into the next! (The -645 was implemented as a 'bag on the side' of the non-segmented -635, so things like this were somewhat inevitable.) > wouldn't you say that the "chunks" on a PDP-11 are invisible to the > user? Unless you are the kernel of course. Or run without protection. No, in MERT 'segments' (called that) were a basic system primitive, which users had access to. (Very cool system! I really need to get moving on trying to recover that...) > *Demand* paging is definitely a separate concept from virtual memory. Hmmm. I understand your definitions, and like breaking things up into 'virtual addressing' (which I prefer as the term, see below), 'non-residence' or 'demand loaded', and 'paging' (breaking into smallish, equal-sized chunks), but the problem with using "virtual memory" as a term for the first is that to most people, that term already has a meaning - the combination of all three. (I have painful memories of this sort of thing - the term 'locator' was invented after we gave up trying to convince people one could have a network architecture in which not all packets contained addresses. That caused a major 'does not compute' fault in most people's brains! And 'locator' has since been perverted from its original definition. But I digress.) > There is no real connection between virtual memory and memory > protection. One can exist with or without the other. Virtual addressing and memory protection; yes, no connection. (Although the former will often give you the latter - if process A can't see, or name, process B's memory, it can't damage it.) > Might have been just some internal early attempt that never got out of DEC? Could be; something similar seems to have happened to the 'RK11-B': http://gunkies.org/wiki/RK11_disk_controller >> I don't have any problem with several different page sizes, _if it >> engineering sense to support them_. > So, would you then say that such machines do not have pages, but have > segments? > Or where do you draw the line? Is it some function of how many different > sized pages there can be before you would call it segments? ;-) No, the number doesn't make a difference (to me). I'm trying to work out what the key difference is; in part, it's that segments are first-class objects which are visible to the user; paging is almost always hidden under the sheets. But not always; some OS's allow processes to share pages, or to map file pages into address spaces, etc. Which does make it complex to separate the two.. Noel

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Re: [TUHS] /dev/drum

by jnc＠mercury.lcs.mit.edu

> From: Johnny Billquist > This is where I disagree. The problem is that the chunks in the PDP-11 > do not describe things from a zero offset, while a segment do. Only > chunk 0 is describing addresses from a 0 offset. And exactly which chunk > is selected is based on the virtual address, and nothing else. Well, you have something of a point, but... it depends on how you look at it. If you think of a PDP-11 address as holding two concatenated fields (3 bits of 'segment' and 13 bits of 'offset within segment'), not so much. IIRC there are other segmented machines that do things this way - I can't recall the details of any off the top of my head. (Well, there the KA10/KI10, with their writeable/write-protected 'chunks', but that's a bit of a degenerate case. I'm sure there is some segmented machine that works that way, but I can't recall it.) BTW, this reminds me of another key differentiator between paging and segments, which is that paging was originally _invisible_ to the user (except for setting the total size of the process), whereas segmentation is explicitly visible to the user. I think there is at least one PDP-11 OS which makes the 'chunks' visible to the user - MERT (and speaking of which, I need to get back on my project of trying to track down source/documentation for it). > Demand paging really is a separate thing from virtual memory. It's a > very bad thing to try and conflate the two. Really? I always worked on the basis that the two terms were synonyms - but I'm very open to the possibility that there is a use to having them have distinct meanings. I see a definition of 'virtual memory' below, but what would you use for 'paging'? Now that I think about it, there are actually _three_ concepts: 'virtual memory', as you define it; what I will call 'non-residence' - i.e. a process can run without _all_ of its virtual memory being present in physical memory; and 'paging' - which I would define as 'use fixed-size blocks'. (The third is more of an engineering thing, rather than high-level architecture, since it means you never have to 'shuffle' core, as systems that used variable-sized things seem to.) 'Non-residence' is actually orthogonal to 'paging'; I can imagine a paging system which didn't support non-residence, and vice versa (either swapping the entire virtual address space, or doing it a segment at a time if the system has segments). > There is nothing about virtual memory that says that you do not have to > have all of your virtual memory mapped to physical memory when the > process is running. True. > Virtual memory is just *virtual* memory. It's not "real" or physical in > the sense that it has a dedicated location in physical memory, which > would be the same for all processes talking about that memory > address. Instead, each process has its own memory, which might be mapped > somewhere in physical memory, but it might also not be. OK so far. > each process would have to be aware of all the other processes that use > memory, and make sure that no two processes try to use the same memory, > or chaos ensues. There's also the System 360 approach, where processes share a single address space (physical memory - no virtual memory on them!), but it uses protection keys on memory 'chunks' (not sure of the correct IBM term) to ensure that one process can't tromp on another's memory. >> a memory management device for the PDP-11 which provided 'real' paging, >> the KT11-B? > have never read any technical details. Interesting read. Yes, we were lucky to be able to retrieve detailed info on it! A PDP-11/20 sold on eBay with a fairly complete set of KT11-B documentation, and allegedly a "KT11-B" as well, but alas, it turned out to 'only' be an RK11-C. Not that RK11-C's aren't cool, but on the 'cool scale' they are like 3, whereas a KT11-B would have been, like, 17! :-) Still, we managed to get the KT11-B 'manual' (such as it is) and prints online. I'd love to find out equivalent detail for the KT11-A, but I've never seen anything on it. (And I've appealed before for the KS11, which an early PDP-11 Unix apparently used, but no joy.) > But how do you then view modern architectures which have different sized > pages? Are they no longer pages then? Actually, there is precedent for that. The original Multics hardware, the GE-645, supported two page sizes. That was dropped in later machines (the Honeywell 6000's) since it was decided that the extra complexity wasn't worth it. I don't have any problem with several different page sizes, _if it makes engineering sense to support them_. (I assume that the rationale for their re-introduction is that in the age of 64-bit machines, page tables for very large 'chunks' can be very large if pages of ~1K or so are used, or something like.) It does make real memory allocation (one of the advantages of paging) more difficult, since there would now be small and large page frames. Although I suppose it wouldn't be hard to coalesce them, if there are only two sizes, and one's a small power-of-2 multiple of the other - like 'fragments' in the Berkeley Fast File System for BSD4.2. I have a query, though - how does a system with two page sizes know which to use? On Multics (and probably on the x86), it's a per-segment attribute. But on a system with a large, flat address space, how does the system know which parts of it are using small pages, and which large? Noel

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Re: [TUHS] /dev/drum

by jnc＠mercury.lcs.mit.edu

> From: Johnny Billquist > Gah. If I were to try and collect every copy made, it would be quite a > collection. Well, just the 'processor handbook's (the little paperback things), I have about 30. (If you add devices, that probably doubles it.) I think my collection is complete. > So there was a total change in terminology early in the 11/45 life, it > would appear. I wonder why. ... I probably would not blame some market > droids. I was joking, but also serious. I really do think it was most likely marketing-driven. (See below for why I don't think it was engineering-driven, which leaves....) I wonder if there's anything in the DEC archives (a big chunk of which are now at the CHM) which would shed any light? Some of the archives are online there, e.g.: http://www.bitsavers.org/pdf/dec/pdp11/memos/ but it seems to be mostly engineering (although there's some that would be characterized as marketing). > one of the most important differences between segmentation and pages are > that with segmentation you only have one contiguous range of memory, > described by a base and a length register. This will be a contiguous > range of memory both in virtual memory, and in physical memory. I agree completely (although I extend it to multiple segments, each of which has the characterstics you describe). Which is why I think the original DEC nomenclature for the PDP-11's memory management was more appropriate - the description above is _exactly_ the functionality provided for each of the 8 'chunks' (to temporarily use a neutral term) of PDP-11 address space, which don't quack like most other 'pages' (to use the 'if it quacks like a duck' standard). One query I have comes from the usual goal of 'virtual memory' (which is the concept most tightly associated with 'pages'), which is to allow a process to run without all of its pages in physical memory. I don't know much about PDP-11 DEC OS's, but do any of them do this? (I.e. allow partial residency.) If not, that would be ironic (in view of the later name) - and, I think, evidence that the PDP-11 'chunks' aren't really pages. BTW, did you know that prior to the -11/45, there was a memory management device for the PDP-11 which provided 'real' paging, the KT11-B? More here: http://gunkies.org/wiki/KT11-B_Paging_Option I seem to recall some memos in the memo archive that discussed it; I _think_ it mentioned why they decided not to go that way in doing memory management for the /45, but I forget the details? (Maybe the performance hit of keeping the page tables in main memory was significant?)_ > With segmentation you cannot have your virtual memory split up and > spread out over physical memory. Err, Multics did that; the process' address space was split up into many segments (a true 2-dimensional naming system, with 18 bits of segment number), which were then split up into pages, for both virtual memory ('not all resident'), and for physical memory allocation. Although I suppose one could view that as two separate, sequential steps - i.e. i) the division into segments, and ii) the division of segments into pages. In fact, I take this approach in describing the Multics memory system, since it's easier to understand as two independent things. > You can also have "holes" in your memory, with pages that are invalid, > yet have pages higher up in your memory .. Something that is impossible > with segmentation, since you only have one set of registers for each > memory type (at most) in a segmented memory implementation. You seem to be thinking of segmentation a la Intel 8086, which is a hack they added to allow use of more memory (although I suspect that PDP-11 chunks were a hack of a similar flavour). At the time we are speaking of, the Intel 8086 did not exist (it came along quite few years later). The systems which supported segmentation, such as Multics, the Burroughs 5000 and successors, etc had 'real' segmentation, with a full two-dimensional naming system for memory. (Burroughs 5000 segment numbers were 10 bits wide.) > I mean, when people talk about segmented memory, what most everyone > today thinks of is the x86 model, where all of this certainly is true. It's also (IMNSHO) irrelevant to this. Intel's brain-damage is not the entirety of computer science (or shouldn't be). (BTW, later Intel xx86 machines did allow you have to 'holes' in segments, via the per-segment page tables.) > it would be very wrong to call what the PDP-11 have segmentation The problem is that what PDP-11 memory management does isn't really like _either_ segmentation, or paging, as practised in other machines. With only 8 chunks, it's not like Multics etc, which have very large address spaces split up into many segments. (And maybe _that_'s why the name was changed - when people heard 'segments' they thought 'lots of them'.) However, it's not like paging on effectively all other systems with paging, because in them paging's used to provide virtual memory (in the sense of 'the process runs with pages missing from real memory'), and to make memory allocation simple by use of fixed-size page frames. So any name given PDP-11 'chunks' is going to have _some_ problems. It just thing 'segmentation' (as you defined it at the top) is a better fit than the alternative... Noel

7 years

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Utility privs

by Ron Natalie

Depending on the system PS may or may not need to be setuid to work by non-root users. Ping needs to be setuid because it uses raw sockets which are restricted (much like opening listens on low number ports) in many systems.

7 years

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Re: [TUHS] rm command

by jnc＠mercury.lcs.mit.edu

> From: William Corcoran > I think it's a bit more interesting to uncover why rm does not remove > directories by default thereby obviating the need for rmdir On early PDP-11 Unixes, 'rm' is an ordinary program, and 'rmdir' is setuid-root, since it has to do special magic (writing into directory files, etc). Given that, it made sense to have 'rm' run with the least amount of privilege needed to do its job. Noel

7 years

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Re: [TUHS] /dev/drum

by jnc＠mercury.lcs.mit.edu

> From: Johnny Billquist > For 1972 I only found the 11/40 handbook. I have a spare copy of the '72 /45 handbook; send me your address, and I'll send it along. (Every PDP-11 fan should have a copy of every edition of every model's handbooks... :-) In the meantime, I'm too lazy to scan the whole thing, but here's the first page of Chapter 6 from the '72: http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/jpg/tmp/PDP11145ProcHbook72pg6-1.j… > went though the 1972 Maintenance Reference Manual for the 11/45. That > one also says "page". :-) There are a few remnant relics of the 'segment' phase, e.g. here: http://minnie.tuhs.org/cgi-bin/utree.pl?file=V6/usr/sys/conf/m45.s which has this comment: / turn on segmentation Also, if you look at the end, you'll see SSR0, SSR1 etc (as per the '72 handbook), instead of the later SR0, SR1, etc. Noel

7 years

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Re: [TUHS] 3330s, 3340s, Winchesters... (was: /dev/drum)

by jnc＠mercury.lcs.mit.edu

> From: Paul Winalski <paul.winalski(a)gmail.com> > Regarding the Winchester code name, I've argued about this with Clem > before. Clem claims that the code name refers to various advances in > disk technology first released in the 3330's disk packs. Wikipedia and > my own memory agree with you that Winchester referred to the 3340. And you believe anything in Wikipedia? If so, I have a bridge to sell you! :-) But, in this case, it's correct. According to "IBM's 360 and Early 370 Computers" (Pugh, Johnson and Palmer - a very good book, BTW), pg. 507, the first Winchester was the 3340. The confusion comes from the fact that it had two spindles, each of 30MB capacity, making it a so-called "30-30" system - that being the name of Winchester's rifle. Noel

7 years

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Re: [TUHS] /dev/drum

by jnc＠mercury.lcs.mit.edu

> From: Johnny Billquist >> Well, the 1972 edition of the -11/45 processor handbook ^^ > It would be nice if you actually could point out where this is the > case. I just went through that 1973 PDP-11/45 handbook ^^ Yes, the '73 one (red/purple cover) had switched. It's only the '72 one (red/white cover) that says 'segments'. Noel

7 years

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Happy birthday, computer mouse!

by Dave Horsfall

Blimey, but I nearly missed this one (I was sick in bed). On this day in 1981, some little company called Xerox PARC introduced something called a "mouse" (mostly because it has a tail), but I'm struggling to find more information about it; wasn't there a photo of a big boxy device? -- Dave Horsfall BSc DTM (VK2KFU) -- FuglySoft -- Gosford IT -- Unix/C/Perl (AbW) People who fail to / understand security / surely will suffer. (tks: RichardM)

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Re: [TUHS] /dev/drum

by Johnny Billquist

On 2018-04-26 04:00, jnc(a)mercury.lcs.mit.edu (Noel Chiappa) wrote: > > From: Johnny Billquist > > > if you hadn't had the ability for them to be less than 8K, you wouldn't > > even try that argument. > > Well, the 1972 edition of the -11/45 processor handbook called them segments..:-) I think we had this argument before as well. It would be nice if you actually could point out where this is the case. I just went through that 1973 PDP-11/45 handbook, and all it says are "page" everywhere I look. I also checked the 1972 PDP-11/40 handbook, and except for one mention of "segment" in the introduction part of the handbook, which is not even clear if it actually specifically refers to the MMU capabilities, that handbook also use the word "page" everywhere. I also checked the PDP-11/20 handbook, but that one does not even cover any MMU, so no mention of neither "page" nor "segment" can be found. > I figure some marketing droid found out that 'paging' was the new buzzword, and > changed the name...:-) :-) Somehow I doubt it, but looking forward to your references... :-) Johnny -- Johnny Billquist || "I'm on a bus || on a psychedelic trip email: bqt(a)softjar.se || Reading murder books pdp is alive! || tryin' to stay hip" - B. Idol

7 years

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/dev/drum

by Tim Bradshaw

I am sure I remember a machine which had this (which would have been running a BSD 4.2 port). Is my memory right, and what was it for (something related to swap?)? It is stupidly hard to search for (or, alternatively, there are just no hits and the memory is false). --tim

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Re: [TUHS] rm command

by jnc＠mercury.lcs.mit.edu

> From: Dave Horsfall <dave(a)horsfall.org> > I am constantly bemused by the number of "setuid root" commands, when a > simple "setgid whatever" will achieve the same task. http://minnie.tuhs.org/cgi-bin/utree.pl?file=V6/usr/sys/ken/sys4.c /* * Unlink system call. */ unlink() { ... if((ip->i_mode&IFMT)==IFDIR && !suser()) goto out; For many things, yes. Not in this particular case. Noel

7 years

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Looking for 3B2 SVR3 driver source code

by Seth Morabito

Hello all, I recently wrote a 3B2/400 simulator on the SIMH platform. It emulates the core system board and peripherals quite well, but I am now turning my attention to the emulating the 3B2 IO expansion boards. The first board I've emulated is the PORTS 4-port serial card, which came together fairly easily because I have the full source code for the SVR3 driver. Other cards, though, are more challenging because I do not have source code for them. I would like to emulate the following two cards: * The CTC cartridge tape controller * The NI 10base5 Ethernet controller Of these two, I have partial source code for the CTC driver (ct.c, ct.h, ct_lla.h, ct_deps.h), but I am missing a core file (ct_lla.c) that would greatly help explain what's going on. And I have NO source code at all for the NI driver. There was a source code package for the NI driver called "nisrc", probably distributed on tape or floppy, but I have never seen it. If you or anyone you know happens to have these source packages and a way to get at them, could you please let me know? I would be grateful. -Seth -- Seth Morabito web(a)loomcom.com

7 years

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Re: [TUHS] rm command

by Doug McIlroy

> Google didn't seem to turn up much on TML Perhaps because there was no TML. I suspect you mean TMG, which I implemented from scratch, based on Bob McClure's original, on both PDP 8 and PDP 11 Unix. Bob Morris and I used it to make EPL, the "early PL/I" compiler for Multics. Off topic, but TMG on the GE 635, usedto buld Multics got there via quite an Odyssey. Bob McClure created it for the CDC 1604. He tranliterated it by hand from 1604 assembly language to IBM 7090 and sent the green coding sheets to me. Debugging it was an unusual exercise: I knew the logic was right; allI had to do was ferret out mistranslations. The most prevalant problem was confusion between CLA (signed load) and CAL (unsigned). When we decided to do EPL, Clem Pease mechanically reproduced a 7090 inside a Ge 635, by defining 7090 instructions as macros--sometimes quite hairy, but they worked. Doug

7 years

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Re: [TUHS] /dev/drum

by Johnny Billquist

On 2018-04-25 16:39, Tom Ivar Helbekkmo<tih(a)hamartun.priv.no> wrote: > > Ron Natalie<ron(a)ronnatalie.com> writes: > >> RK05’s were 4872 blocks. Don’t know why that number has stuck with >> me, too many invocations of mkfs I guess. Oddly, DEC software for >> some reason never used the last 72 blocks. > I guess that's because they implemented DEC Standard 144, known as > bad144 in BSD Unix. It's a system of remapping bad sectors to spares at > the end of the disk. I had fun implementing that for the wd (ST506) > disk driver in NetBSD, once upon a time... Uh... DEC STD 144 does not have anything to do with remapping bad blocks to replacement good blocks. DEC STD 144 describes how a media stores known bad blocks on a disk, so that file system initialization can then take whatever action needed to that these blocks are not used by anything. In RSX (and VMS), they will be included in a file called BADBLK.SYS, and thus be perceived as "used". bad144 in NetBSD will keep the a table in memory for such disks, and "skip" blocks listed in the list as bad, meaning all other blocks gets shifted. So it sortof do a remapping to good blocks by extending the used blocks, and does not allocate anything at the end of the disk per se. However, that is a Unix specific solution. OS/8 had a similar solution for RL01 and RL02 drives, but not RK05 (as RK05 disks don't follow DEC STD 144.) I don't know exactly why DEC left the last three tracks unused. Might have been for diagnostic tools to have a scratch area to play with. Might have been that those tracks were found to be less reliable. Or maybe something completely different. But it was not for bad block replacement, as DEC didn't even do that on RK05 (or more or less in general at all before MSCP. MSCP, by the way, does not use DEC STD 144.) Something Unix and other implementations usually miss with DEC STD 144 is that there are actually two tables with bad blocks defined by the standard. There is the manufacturer defined bad blocks, which all software seems to know and deal with, and there are the user defined bad blocks, which are supposed to be where all bad blocks that develop after manufacture are supposed to be placed. Lots of software does not deal with this second list. In addition, you also have the pack serial number and some stuff defined by DEC STD 144, which is also recorded on the last track, where the bad block lists also are stored. Note that this information is supposed to be on the last track, meaning you cannot use the scheme Unix uses to remap bad blocks, unless you keep some blocks before the last track unallocated. The ultimate irony was when I discovered that bad144 under NetBSD was only built for x86 machine, and not being built for VAX, which is the only architecture supported which actually have real disks which follow the DEC STD 144. But that was corrected about 20 years ago now (time flies). Johnny -- Johnny Billquist || "I'm on a bus || on a psychedelic trip email: bqt(a)softjar.se || Reading murder books pdp is alive! || tryin' to stay hip" - B. Idol

7 years

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Re: [TUHS] /dev/drum

by jnc＠mercury.lcs.mit.edu

> From: Johnny Billquist > if you hadn't had the ability for them to be less than 8K, you wouldn't > even try that argument. Well, the 1972 edition of the -11/45 processor handbook called them segments.. :-) I figure some marketing droid found out that 'paging' was the new buzzword, and changed the name... :-) :-) Noel

7 years

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Re: [TUHS] /dev/drum

by Johnny Billquist

On 2018-04-26 00:55, jnc(a)mercury.lcs.mit.edu (Noel Chiappa) wrote: > > From: Johnny Billquist > > > PDP-11 have 8K pages. > > Segments.:-) (This is an old argument between Johnny and me, I'm not trying > to re-open it, just yanking his chain...:-) :-) And if you hadn't had the ability for them to be less than 8K, you wouldn't even try that argument. But just because the hardware gives you some extra capabilities, you suddenly want to associate them with a technology that really gives you much less capabilities. Either way, the next page always start at the next 8K boundary. > > On a PDP-11, all your virtual memory was always there when the process > > was on the CPU > > In theory, at least (I don't know of an OS that made use of this), didn't the > memory management hardware allow the possibility to do demand-paging? I note > that Access Control Field value 0 is "non-resident". Oh yes. You definitely could do demand paging based on the hardware capabilities. > Unix kinda-sorta used this stuff, to automatically extend the stack when the > user ran off the end of it (causing a trap). Ah. Good point. The same is also true for brk, even though that is an explicit request to grow your memory space at the other side. DEC OSes had the brk part as well, but stack was not automatically extended if needed. DEC liked to have the stack at the low end of address space, and have hardware that trapped if the stack grew below 400 (octal). > > you normally did not have demand paging, since that was not really > > gaining you much on a PDP-11 > > Especially on the later machines, with more than 256KB of hardware main > memory. Maybe it might have been useful on the earlier ones (e.g. the -11/45). Yeah, it would actually probably have been more useful on an 11/45. Johnny -- Johnny Billquist || "I'm on a bus || on a psychedelic trip email: bqt(a)softjar.se || Reading murder books pdp is alive! || tryin' to stay hip" - B. Idol

7 years

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Re: [TUHS] /dev/drum

by jnc＠mercury.lcs.mit.edu

> From: Johnny Billquist > PDP-11 have 8K pages. Segments. :-) (This is an old argument between Johnny and me, I'm not trying to re-open it, just yanking his chain... :-) > On a PDP-11, all your virtual memory was always there when the process > was on the CPU In theory, at least (I don't know of an OS that made use of this), didn't the memory management hardware allow the possibility to do demand-paging? I note that Access Control Field value 0 is "non-resident". Unix kinda-sorta used this stuff, to automatically extend the stack when the user ran off the end of it (causing a trap). > you normally did not have demand paging, since that was not really > gaining you much on a PDP-11 Especially on the later machines, with more than 256KB of hardware main memory. Maybe it might have been useful on the earlier ones (e.g. the -11/45). Noel

7 years

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Re: [TUHS] /dev/drum

by Johnny Billquist

On 2018-04-25 23:14, Paul Winalski <paul.winalski(a)gmail.com> wrote: > On 4/25/18, Ronald Natalie > <ron(a)ronnatalie.com> wrote: >> The fun argument is what is Virtual Memory. Typically, people align that >> with paging but you can stretch the definition to cover paging. >> This was a point of contention in the early VAX Unix days as the ATT (System >> III, even V?) didn’t support paging on the VAX where as BSD did. > In my book, virtual memory is any addressing scheme where the > addresses that the program uses are different from the physical memory > addresses. Nowadays most OSes use a scheme where each process has its > own virtual address space, and virtual memory is demand-paged from > backing store on disk. But there have been other schemes. Yeah... > Some PDP-11 models had a virtual addressing feature called PLAS > (Program Logical Address Space). The PDP-11 had 16-bit addressing, > allowing for at most 64K per process. To take advantage of physical > memory larger than 64K, PLAS allowed multiple 64K virtual address > spaces to be mapped to the larger physical memory. Sort of the > reverse of the usual virtual addressing scheme, where there is more > virtual memory than physical memory. Note that PLAS is not a PDP-11 hardware thing. PLAS was the name for the mechanism provided by the OS for applications to be able to access more than 64K of memory while still be limited by the virtual address space limit of 64K. PLAS is in one way very similar to mmap, except that it's not backed by a file. But you create a memory region though the OS (giving it a name and a size, which can be more than 64K), and then you can map to it, specifying the offset into it and window size, as well as where to map to in your virtual address space. This is realized by just using the pages of the MMU of the PDP-11 map to different parts and things. Any OS that had the PLAS capability by necessity had to have an MMU, which was the hardware part that allowed this to be implemented. So, all PDP-11s with an MMU could allow the OS running on it to provide the PLAS capabilities. A PDP-11 in general is "reversed" in that the physical address space is much larger than the virtual one. Although, the same was also true on the VAX in the last iteration where the NVAX implementation allowed for a 34 bit physical address, while the virtual address space was still only 32 bits. But that doesn't make the virtual memory any less virtual. Johnny -- Johnny Billquist || "I'm on a bus || on a psychedelic trip email: bqt(a)softjar.se || Reading murder books pdp is alive! || tryin' to stay hip" - B. Idol

7 years

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Re: [TUHS] /dev/drum

by jnc＠mercury.lcs.mit.edu

> From: Johnny Billquist > I don't know exactly why DEC left the last three tracks unused. Might > have been for diagnostic tools to have a scratch area to play with. > Might have been that those tracks were found to be less reliable. Or > maybe something completely different. But it was not for bad block > replacement, as DEC didn't even do that on RK05 The "pdp11 peripherals handbook" (1975 edition at least, I can't be bothered to check them all) says, for the RK11: "Tracks/surface: 200+3 spare" and for the RP11: "Tracks/surface: 400 (plus 6 spares)" which sounds like it could be for bad block replacement, but the RP11-C Maintenance Manual says (pg. 3-10) "the inner-most cylinders 400-405 are only used for maintenance". Unix blithely ignored all that, and used every block available on both the RK11 and RP11. Noel

7 years

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Re: [TUHS] /dev/drum

by Johnny Billquist

On 2018-04-25 16:39, arnold(a)skeeve.com wrote: > Tim Bradshaw<tfb(a)tfeb.org> wrote: > >> Do systems with huge pages page in the move-them-to-disk sense I wonder? >> I assume they don't in practice because it would be insane but I wonder >> if the VM system is in theory even willing to try. > Why not? If there's enough backing store availble? > > Note that many systems demand page-in the code section straight out of the > executable, so if some of those pages aren't needed, they can just > be released. And said pages can be shared among all processes running > the same executable, for further savings. Right. >> Something I never completely understood in the paging vs swapping >> thing was that I think that systems which could page (well, 4.xBSD in >> particular) would*also* swap if pushed. I think the reason for that was >> that, if you were really short of memory, swapping freed up the process >> structure and also the page tables &c for the process, which would still >> be needed even if all its pages had been evicted. Is that right? > It depends upon the system. Some had pageable page tables, which is > pretty hairy. Others didn't. I don't remember what 4BSD did on the > Vax, but I suspect that the page tables and enough info to find everything > on swap stayed in kernel memory. (Where's Chris Torek when you need > him?:-) The pages tables describing the users memory space are themselves located in virtual memory on the VAX, so they can be paged out without problem. If you refer to an entry in the user page table, and that page itself is paged out, you'll get a page fault for the system page table, so you'll need to page in that page of the system. But I seem to remember 4BSD (as well as NetBSD) keep all of the kernel in physical memory all the time, and don't page the kernel parts, including process page tables. > But yes, swapping was generally used to free up large amounts of memory > if under heavy load. Paging would free up the same amount of memory, if we talk about the memory used by the process itself. However, there are various meta data in the kernel itself that is needed for a process, which will remain in memory even if no pages are in memory. Swapping will also move non-essential kernel structures out to disk for the process, in addition to the pages. Thus, there is a difference between swapping and paging. The whole process context for example. Which includes both the page tables as well as the kernel mode stack for the process, processor registers, and possibly also open file contexts, and probably some other things I'm forgetting now. Very little needs to be kept in memory for a process if you are not interested in resuming it on short notice. Johnny -- Johnny Billquist || "I'm on a bus || on a psychedelic trip email: bqt(a)softjar.se || Reading murder books pdp is alive! || tryin' to stay hip" - B. Idol

7 years

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rm command

by Eric Blood

I came across this yesterday: > Fun fact: according to unsubstantiated UNIX lore, "rm" is NOT short-hand > for "remove" but rather, it stands for the initials of the developer that wrote > the original implementation, Robert Morris. > > https://news.ycombinator.com/item?id=16916565 I was curious if there's any truth to it. I found http://minnie.tuhs.org/cgi-bin/utree.pl and was poking around but couldn't determine when the rm command came about. Thoughts? -- Eric Blood winkywooster(a)gmail.com

7 years

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Re: [TUHS] /dev/drum

by Johnny Billquist

On 2018-04-25 16:39, Ronald Natalie<ron(a)ronnatalie.com> wrote: > >> On Apr 24, 2018, at 9:27 PM, Dan Stromberg<drsalists(a)gmail.com> wrote: >> >> On Sun, Apr 22, 2018 at 2:51 PM, Dave Horsfall<dave(a)horsfall.org> wrote: >>> Now, how many youngsters know the difference between paging and swapping? >> I'm a mere 52, but I believe paging is preferred over swapping. >> >> Swapping is an entire process at a time. >> >> Paging is just a page of memory at a time - like 4K or something thereabout. > Early pages were 1K. What machines are we talking about then? PDP-11 have 8K pages. VAX have 512 byte pages, if we talk about hardware. (And yes, I know pages on PDP-11s are not fixed in size, but if you want the page to go right up to the next page, it's 8K.) > The fun argument is what is Virtual Memory. Typically, people align that with paging but you can stretch the definition to cover paging. > This was a point of contention in the early VAX Unix days as the ATT (System III, even V?) didn’t support paging on the VAX where as BSD did. > Our comment was that “It ain’t VIRTUAL memory if it isn’t all there” as opposed to virtual addressing. Weird comment. What does that mean? On a PDP-11, all your virtual memory was always there when the process was on the CPU, but it might not be there at other times. Just as not all processes memory would be in physical memory all the time, since that often would require more physical memory than you had. But you normally did not have demand paging, since that was not really gaining you much on a PDP-11. On the other hand, overlays do the same thing for you, but in userspace. So you would claim that ATT Unix did not have virtual memory because it didn't do demand paging? Johnny -- Johnny Billquist || "I'm on a bus || on a psychedelic trip email: bqt(a)softjar.se || Reading murder books pdp is alive! || tryin' to stay hip" - B. Idol

7 years

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Re: [TUHS] [TUHS} rm command

by Doug McIlroy

Fake news knocks on the doors of Unixland: there's absolutely no truth to the claim that the rm command was written by Robert Morris. Rm was there from the beginning, when only two people wrote Unix code--Thompson and Ritchie. In fact, it would have been on PDP8 Unix, which Morris never used. Doug

7 years

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Re: [TUHS] VAX dates (was /dev/drum)

by Paul Winalski

On 4/22/18, Clem cole <clemc(a)ccc.com> wrote: > > BTW if you want to be correct about dates - the DEC released the Vax in 76 > not 78 ( I personally used to program Vax serial #1 at CMU under VMS 1.0 > before I was at UCB which is what Dan had asked). As I remember it, DEC announced the VAX in 1976 or 1977, and first official customer ship didn't happen until 1978. Holy Cross had one of the hardware beta machines in 1977. It ran a beta version of VMS (version X0.5 initially). I ported a bunch of programs to the VAX, including the PDP-10 version of Adventure. -Paul W.

7 years

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Re: [TUHS] /dev/drum

by Johnny Billquist

On 2018-04-24 01:30, Grant Taylor <gtaylor(a)tnetconsulting.net> wrote: > On 04/23/2018 04:15 PM, Warner Losh wrote: >> It's weird. These days lower LBAs perform better on spinning drives. >> We're seeing about 1.5x better performance on the first 30% of a drive >> than on the last 30%, at least for read speeds for video streaming.... > I think manufacturers have switched things around on us. I'm used to > higher LBA numbers being on the outside of the disk. But I've seen > anecdotal indicators that the opposite is now true. That must have been somewhere in the middle of history in that case. Old (proper) drives had/have track 0 at the outer edge. The disk loaded the heads after spin up, and that was at the outer edge, and then you just locked on to track 0, which should be near. Heads had to be retracted for the disk pack to be replaced. But this whole optimization for swap based on transfer speeds makes no sense to me. The dominating factor in spinning rust is seek times, and not transfer speed. If you place the swap at one end of the disk, it won't matter much that transfers will be faster, as seek times will on average be much longer, and that will eat up any transfer gain ten times over before even thinking. (Unless all your disk ever does is swapping, at which time the heads can stay around the swapping area all the time.) Which is also why the file system for RSX (ODS-1) placed the index file (equivalent of the inode table) at the middle of the disk by default. Not sure if Unix did that optimization, but I would hope so. (Never dug into that part of the code.) Johnny -- Johnny Billquist || "I'm on a bus || on a psychedelic trip email: bqt(a)softjar.se || Reading murder books pdp is alive! || tryin' to stay hip" - B. Idol

7 years

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Happy birthday, Niklaus Wirth!

by Dave Horsfall

Computer pioneer Niklaus Wirth was born on this day in 1934; he basically designed ALGOL, one of the most influential languages ever, with just about every programming language in use today tracing its roots to it. His name is pronounced "vurt" but he would accept "worth", and he joked that you could call him by name or by value (you need to know ALGOL to understand). -- Dave Horsfall DTM (VK2KFU) "Those who don't understand security will suffer."

7 years

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Re: [TUHS] /dev/drum

by Rudi Blom

>Date: Mon, 23 Apr 2018 13:51:07 -0400 >From: Clem Cole <clemc(a)ccc.com> >To: Ron Natalie <ron(a)ronnatalie.com> >Cc: Tim Bradshaw <tfb(a)tfeb.org>, TUHS main list <tuhs(a)minnie.tuhs.org> >Subject: Re: [TUHS] /dev/drum >Message-ID: > <CAC20D2PEzAayjfaQN+->kQS=H7npcEZ_OKXL1ffPxak5b2ENv4Q(a)mail.gmail.com> >Content-Type: text/plain; charset="utf-8" ... some stuff removed ... >Exactly... For instance an RK04 was less that 5K blocks (4620 or some >such - I've forgotten the actually amount). The disk was mkfs'ed to the >first 4K and the left over was give to the swap system. By the time of >4.X, the RP06 was 'partitioned' into 'rings' (some overlapping). The 'a'. >partition was root, the 'b' was swap and one fo the others was the rest. >Later the 'c' was a short form for copying the entire disk. Wondered why, but I guess now I know that's the reason Digital UNIX on alpha used the same disk layout. From a AlphaServer DS10 running DU4.0g, output "disklabel -r rz16a" # /dev/rrz16a: type: SCSI disk: BB009222 label: flags: bytes/sector: 512 sectors/track: 168 tracks/cylinder: 20 sectors/cylinder: 3360 cylinders: 5273 sectors/unit: 17773524 rpm: 7200 interleave: 1 trackskew: 66 cylinderskew: 83 headswitch: 0 # milliseconds track-to-track seek: 0 # milliseconds drivedata: 0 8 partitions: # size offset fstype [fsize bsize cpg] # NOTE: values not exact a: 524288 0 AdvFS # (Cyl. 0 - 156*) b: 1572864 524288 swap # (Cyl. 156*- 624*) c: 17773524 0 unused 0 0 # (Cyl. 0 - 5289*) d: 0 0 unused 0 0 # (Cyl. 0 - -1) e: 0 0 unused 0 0 # (Cyl. 0 - -1) f: 0 0 unused 0 0 # (Cyl. 0 - -1) g: 4194304 2097152 AdvFS # (Cyl. 624*- 1872*) h: 11482068 6291456 AdvFS # (Cyl. 1872*- 5289*)

7 years, 1 month

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Re: [TUHS] /dev/drum

by jnc＠mercury.lcs.mit.edu

> From: "Ron Natalie" > I'm pretty sure that swapping in V6 took place to a major/minor number > configured at kernel build time. Yup, in c.c, along with the block/character device switches (which converted major device numbers to routines). > You could create a dev node for the swap device, but it wasn't used for > the actual swapping. Yes. > We actually dedicated a full 1024 block RF11 fixed head to the system in > the early days Speaking of fixed-head disks, one of the Bell systems used (IIRC) an RS04 fixed-head disk for the root. DEC apparently only used that disk for swapping in their OS's... So the DEC diagnsotics felt free to scribble on the disk. So, Field Circus comes in to work on the machine... Ooops! Noel

7 years, 1 month

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Re: [TUHS] /dev/drum

by jnc＠mercury.lcs.mit.edu

> From: Clem Cole > To be honest, I really don't remember - but I know we used letters for > the different partitions on the 11/70 before BSD showed up. In V6 (and probably before that, too), it was numbers: http://minnie.tuhs.org/cgi-bin/utree.pl?file=V6/usr/man/man4/rp.4 So on my machine which had 2 x 50MB CalChomps, with a Diva controller, which we had to split up into two partition each (below), they were dv00, dv01, dv10 and dv11. Letters for the partitions made it easier... > The reason for the partition originally was (and it must have been 6th > edition when I first saw it), DEC finally made a disk large enough that > number of blocks overflowed a 16 bit integer. So splitting the disk > into smaller partitions allowed the original seek(2) to work without > overflow. No, in V6 filesystems, block numbers (in inodes, etc - also the file system size in the superblock) were only 16 bits, so a 50MB disk (100K blocks) had to be split up into partitions to use it all. True of the RP03/04 in V6 too (see the man page above). Noel

7 years, 1 month

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Re: [TUHS] [GROFF] groff as a asis for comprehensive documentation

by Doug McIlroy

Ingo wrote: > i have been working hard to reduce the number of options of low usefulness Ah, soothing classical Unix Musik, so rare in the cacophonous Linux era. Doug

7 years, 1 month

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Happy birthday, Ray Tomlinson!

by Dave Horsfall

Ray Tomlinson, computer pioneer, was born on this day in 1941. He is credited with inventing this weird thing called "email" on the ARPAnet, in particular the "@" sign to designate a remote host (although some jerk -- his name is not important -- is claiming that he was first). -- Dave Horsfall DTM (VK2KFU) "Those who don't understand security will suffer."

7 years, 1 month

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Re: [TUHS] /dev/drum

by Norman Wilson

Clem Cole: On the other hand, we still 'dump core' and use the core files for debugging. So, while the term 'drum' lost its meaning, 'core file' - might be considered 'quaint' by todays hacker, it still has meaning. ==== Just as we still speak of dialling and hanging up the phone, electing Presidents, and other actions long since made obsolete by changes of technology and culture. Norman Wilson Toronto ON

7 years, 1 month

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Re: [TUHS] /dev/drum

by jnc＠mercury.lcs.mit.edu

> From: Warner Losh > Drum memory stopped being a new thing in the early 70's. Mid 60's. Fixed-head disks replaced them - same basic concept, same amount of bits, less physical volume. Those lasted until the late 70's - early PDP-11 Unixes have drivers for the RF11 and RS0x fixed-head disks. The 'fire-hose' drum on the GE 645 Multics was the last one I've heard of. Amusing story about it here: http://www.multicians.org/low-bottle-pressure.html Although reading it, it may not have been (physically) a drum. > There never was a drum device, at least a commercial, non-lab > experiment, for the VAXen. They all swapped to spinning disks by then. s/spinning/non-fixed-head/. Noel

7 years, 1 month

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MRS database software ca. 1979

by Dennis Boone

Does anyone know if UToronto's MRS database system (from about 1979) has survived? It was described in: Robert Hudyma, John Kornatowski, Ivor Ladd. MRS: A microcomputer database management system. Proceedings of the 1981 ACM SIGSMALL symposium on Small systems and SIGMOD workshop on Small database systems, pp 174-180. Apparently it was distributed to over 50 unix sites. This is the software which became the MISTRESS and later EMPRESS products. De

7 years, 1 month

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CTIX Provenance

by Lyndon Nerenberg

The recent Empress and earlier PC[67]300 conversations have churned my failing memory to catch up on the CTIX versions I ran throughout the 1980s. I (sort of) remember 5.x and 6.x as being the releases we faced. The 5.x ones were derived from SVR1 IIRC. When 6.x arrived, SVR2+ was the order of the day, but I don't recall much or anything of SVR3 creeping in. Certainly no RFS or the like. And Convergent wasn't shy about letting bits of Berkeley code sneak in when that made sense. I think the UUCP code got a significant update between 5 and 6. Didn't the 5.x uucico have the "window > 3 == core dump" bug? By 6.x I recall it grew 'G' protocol (at least). Any ex-Convergent hacks on the list who can fill in the blanks? --lyndon

7 years, 1 month

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RIP Dick Hustvedt

by Dave Horsfall

We lost software engineer Dick Hustvedt on this day in 2008, following severe injuries in a vehicle accident. He contributed much to RSX-11 and VMS, including the infamous "microfortnight" and the SD730 Fixed Head Solar Horologue. An obituary of him can be found at http://software.intel.com/en-us/blogs/2008/04/23/dick-hustvedt-the-consumma… (and it's worth reading). -- Dave Horsfall DTM (VK2KFU) "Those who don't understand security will suffer."

7 years, 1 month

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RIP Robert Taylor

by Dave Horsfall

We lost Robert Taylor, computer scientist and Internet pioneer, on this day in 2017. Amongst other things, he helped invent the mouse, pioneered computer communications leading up to ARPAnet, developed the computer science lab at Xerox... -- Dave Horsfall DTM (VK2KFU) "Those who don't understand security will suffer."

7 years, 1 month

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Minor Milestone: Venix 86 "user mode" interpreter

by Warner Losh

Today I reached a minor milestone with my 'Venix restoration project' that I talked about months ago. I ran a Venix 86 binary (sync) to successful completion on my FreeBSD/amd64 box (though none of the code should be too FreeBSD specific). So, I hacked https://github.com/tkchia/reenigne.git to remove the DOS loader and emulator and to add a Venix system call loader and emulator, or at least the start of one. I've also added FP instruction parsing, but it's 100% wrong (it just parses the instructions and does nothing else to decode or implement them). With this, I'm able to load OMAGIC binaries from the extant venix 86 distributions and run them. The only one that runs successfully is sync() since I've not yet implemented argument passing or any of the other 58 system calls :). NMAGIC should be pretty quick after this. This is but a step on the road to getting the Venix compiler running so I can see how much of the system I can recreate from the v7 and other sources that are on TUHS. Not sure who, if anybody, cares about this stuff. I thought people here might be interested. I've pushed the results to https://github.com/bsdimp/venix if you care. This program is in the tools/86sim directory. There's also a doc directory where I document the Venix 86 ABI, as well as doing a very deep-dive into a disassembled /bin/sync to discover what I can from it (turns out, it's quite a lot). So, I thought I'd share this here. Don't know if anybody else is interested, but you never know until you tell people about stuff... Warner

7 years, 1 month

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A Legal History of Unix

by Warren Toomey

I was sure that I'd read a paper on the legal history of Unix. So I did a Google search for it, and found a link to the PDF. The linked PDF was on the TUHS website :-) http://wiki.tuhs.org/lib/exe/fetch.php?media=publications:theses:gmp_thesis… I'd better do a backup of my brain, as I've got a few flakey DRAM chips. Cheers, Warren

7 years, 1 month

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Re: [TUHS] Happy birthday, Internet!

by jnc＠mercury.lcs.mit.edu

> From: Clem Cole > first of Jan 83 was the day the Arpanet was supposed to be turned off Err, NCP, not the ARPANet. The latter kept running for quite some time, serving as the Internet's wide-area backbone, and was only slowly turned off (IMP by IMP) in the late 80's, with the very last remnants finally being turned off in 1990. > The truth is, it did not happen, there were a few exceptions granted for > some sites that were not quite ready (I've forgotten now). A few, yes, but NCP was indeed turned off for most hosts on January 1, 1983. > From: "Erik E. Fair" > as of the advent of TCP/IP, all those Ethernet and Chaosnet connected > workstations became first class hosts on the Internet, which they > could not be before. Huh? As I just pointed out, TCP/IP (and the Internet) was a going concern well _before_ January 1, 1983 - and one can confidently say that even had NCP _not_ been turned off, history would have proceeded much as it actually did, since all the machines not on the ARPANET would have wanted to be connected to the Internet. (Also, to be technical, I'm not sure if TCP/IP ever really ran on CHAOSNet hardware - I know I did a spec for it, and the C Gateway implemented it, and there was a Unix machine at EECS that tried to use it, but it was not a great success. Workstations connected to the CHAOSNet as of that date - AFAIK, just LISP Machines - could only get access to the Internet via service gateways, since at that point they all only implemented the CHAOS protocols; Symbolics did TCP/IP somewhat later, IIRC, although I don't know the exact date.) Noel

7 years, 1 month

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Software Tools now in Wikipedia

by Doug McIlroy

> I rewrote the article on the Software Tools project An excellent job, Deborah. > the Software Tools movement established one of the earliest traditions of open source Would you be open to saying "reestablished"? Open source (not so called, and in no way portable) was very much a tradition of SHARE in the late 1950s. Portability, as exemplified in ACM's collected algorithms, came in at the same time that industry moved to a model of trade secrets and intellectual property. Open source went into eclipse. Doug

7 years, 1 month

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Software Tools now in Wikipedia

by Deborah Scherrer

I rewrote the article on the Software Tools project and, thanks to Bruce Borden's efforts to upload, they accepted it within 1 day. You can see it here: https://en.wikipedia.org/wiki/Software_tools_users_group The Usenix article in Wiki is pretty thin, in case anyone would like to spiffy it up. Deborah

7 years, 1 month

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Re: [TUHS] Happy birthday, Internet!

by jnc＠mercury.lcs.mit.edu

> From: Steve Nickolas > I thought the epoch of the Internet was January 1, 1983. Turning off NCP was a significant step, but not that big a deal in terms of its actual effects, really. For those of us already on the Internet before that date (since as the number of ARPANet ports was severely limited, for many non-ARPANet-connected machines - which were almost all time-sharing systems, at that point in time, so lots of actual users - there was a lot of value in an Internet connection, so there were quite a few), it didn't produce any significant change - the universe of machines we could talk to didn't change (since we could only talk to ARPANet-connected machines with TCP), etc. And for ARPANET-connected machines, there too, things didn't change much - the services available (remote login, email, etc) remained the same - it was just carried over TCP, not NCP. I guess in some sense it marked 'coming of age' for TCP/IP, but I'd analogize it to that, rather than a 'birth' date. Noel

7 years, 1 month

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Re: [TUHS] Happy birthday, Internet!

by jnc＠mercury.lcs.mit.edu

> From: Clem Cole > Katie Hafner's: Where Wizards Stay Up Late: The Origins Of The Internet > ... > It's a great read Yes, she did a great deal of careful research, and it's quite accurate. It _is_ pointed toward a general readership, not a technical one, so it's not necessarily the best _technical_ history (which she had the material at hand to produce, had she wanted to - but did not). Still, very worthwhile. Noel

7 years, 1 month

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That "SPL 0" instruction...

by Dave Horsfall

A nerdy group on an Aussie list are discussing old Unix cracks, and the infamous "SPL 0" brick-that-box came up. I first saw it in ";login:" (I think), and, err, tried it (as did others)... Can anyone reproduce the code? It went something like: > [ SPL 0 ] > > I only did that once (and you should've heard what he said to me)... > I'm still trying to find the source for it (it was published in a > ";login:" journal) to see if SIMH is vulnerable. The concept was simple enough - fill your entire memory space with an uninterruptible instruction. It would have gone something like: opc = 000230 ; 000230 is the opcode for SPL 0 sys brk, -1 ; or whatever value got you all 64k of address space mov #place, sp jmp place . = opc - 2 ; the -2 is to allow for the PC increment on an instruction fetch, which I believe happens before any execution place: jsr pc, -(pc) Ring any bells, anyone? -- Dave Horsfall DTM (VK2KFU) "Those who don't understand security will suffer."

7 years, 1 month

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Re: [TUHS] Happy birthday, Internet!

by jnc＠mercury.lcs.mit.edu

> From: Dave Horsfall > The Internet ... was born on this day in 1969, when RFC-1 got published I have this vague memory that the Internet-History list decided that the appropriate day was actually the day the format of the v4 headers was set, i.e. 16 June, 1978. (See IEN-68, pg. 12, top.) Picking the date of RFC-1 seems a little odd. Why not the day the first packet was send over a deployed IMP, or the day the RFP was sent out, or the contract let? And the ARPANet was just one predecessor; one might equally have picked a CYCLADES date... > (spelled with a capital "I", please, as it is a proper noun) ... As I > said at a club lecture once, there are many internets, but only one > Internet. I myself prefer the formulation 'there are many white houses, but only one White House'! :-) Noel

7 years, 1 month

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Happy birthday, J. Presper Eckert!

by Dave Horsfall

J. Presper Eckert was born on this day in 1919; along with John Mauchly, he was a co-designer of ENIAC, one of the world's first programmable electronic computers. Yes, there is a long-running dispute over whether ENIAC or Colossus was first; being a Pommie, I'm siding with Colossus :-) -- Dave Horsfall DTM (VK2KFU) "Those who don't understand security will suffer."

7 years, 1 month

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Re: [TUHS] long lived programs

by Norman Wilson

Steve Johnson: But in this case, part of the requirement was to pass some standard simulation tests (in FORTRAN, of course). He was complaining that these programs had bugs and didn't give the right answer. ==== This reminds me of an episode during my time at Bell Labs. The System V folks wanted to make pipes that were streams; our experience in Research showed that that was useful. We'd done it just by making pipe(2) create a stream. This caused some subtle differences in semantics (pipes became full-duplex; writing to a pipe put a delimiter in the stream, so that a corresponding read on the other end would stop at the delimiter; write(pipefd, "", 0) therefore generated something that would make read(pipeotherfd, buf, len) return 0). We'd been running all our systems that way for a while, and had uncovered no serious problems. But the System V folks were very nervous about it anyway, and wrote a planning document in which they proposed to create a new, different system call to make stream pipes. pipe(2) would make an old-fashioned pipe; spipe(2) (or whatever it was called, I forget the name) had to be called to get a stream. The document didn't really explain the justification for this. To us in Research it just sounded crazy. Someone else was going to attend a meeting with the developers, but at the last minute he had a conflict, so he drafted me to go. Although I can be pretty blunt in writing, I try not to be so much so in person when dealing with people I don't know; so rather than asking how they could be so crazy as to add a new kind of pipe, I asked why they really thought it necessary. It took a little probing, but the answer turned out to be that their management insisted that everything pass an official verification suite to prove compliance with the System V, Consider It Standard; and said verification suite didn't just check that the first file descriptor returned by pipe(2) could be read and the second written, it insisted that the first could not be written and the second not read. Full-duplex pipes didn't meet the standard, it was claimed. I asked what exactly is the standard? The SVID, I was told. What does the SVID really say, I wondered? We got a copy and looked up pipe(2). According to the official standard, the first file descriptor must be readable and the second writeable, but there was no statement that it couldn't work the other way too. Full-duplex pipes did in fact meet the standard; it was the verification suite that, in an excess of zeal, didn't conform. The developers were absolutely delighted with this. They too thought it was stupid to have two different kinds of pipes, particularly given our experience that full-duplex delimited pipes didn't break anything. They were very happy to have Research not just yell at them for doing things differently from us, but help them figure out how to justify doing things right. I don't know just how they took this further with management, but as it came out in SVr4, pipe(2) returned a full-duplex stream. This is still true even unto Solaris 10, where I just tested it. I made friends that day. That developer group kept in touch with me as they did further work on pipes, the terminal driver, pseudo-ttys, and other things. I didn't agree with everything they did, but we were able to discuss it all cordially. Sometimes the verification program just needs to be fixed. And sometimes the developers that seem set on doing the wrong thing really want help in subverting whatever is forcing that on them, because they really do know what the right thing is. Norman Wilson Toronto ON

7 years, 1 month

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Re: [TUHS] Happy birthday, Internet!

by Rudi Blom

Just had a look at RFC-1, my first look ever. First thing I noticed is the enormous amount of abbreviations one is assumed to be able to instantly place :-) So looking up IMP for instance the wiki page gives me this funny titbit "When Massachusetts Senator Edward Kennedy learned of BBN's accomplishment in signing this million-dollar agreement, he sent a telegram congratulating the company for being contracted to build the "Interfaith Message Processor"." https://en.wikipedia.org/wiki/Interface_Message_Processor

7 years, 1 month

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Re: [TUHS] long lived programs

by Doug McIlroy

> Shortly after I arrived, the comp center announced a brand-new feature -- permanent disc storage! (actually, I think it was a drum...) Irrelevant to the story (or Unix), but it was indeed a disc drive--much more storage per unit volume than drums, which date to the 1940s, if not before. Exact opposite of current technology: super heavy and rigid combs banged in and out of the disk stack. The washing-machine sized machine could be driven to walk across the floor. It would not be nice to be caught in its path. (Fortunately ordinary work loads did not have such an effect.) Vic Vyssotsky calculated that with only 10 times its 10MB capacity, we could have kept the entire printed output since the advent of computers at the Labs on line. Doug

7 years, 1 month

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Happy birthday, Internet!

by Dave Horsfall

The Internet (spelled with a capital "I", please, as it is a proper noun) was born on this day in 1969, when RFC-1 got published; it described the IMP and ARPAnet. As I said at a club lecture once, there are many internets, but only one Internet. -- Dave Horsfall DTM (VK2KFU) "Those who don't understand security will suffer."

7 years, 1 month

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Re: [TUHS] shared objects in Unix (Clem cole) / Accent influence

by Paul Ruizendaal

> Date: Fri, 30 Mar 2018 00:28:13 -0400 > From: Clem cole <clemc(a)ccc.com> > > Also, joy / BSD 4.2 was heavily influenced by Accent (and RIG )and the Mach memory system would eventually go back into BSD (4.3 IIRC) - which we have talked about before wrt to sockets and Accent/Mach’s port concept. From an "outsider looking in” perspective I’m not sure I recognise such heavy influence in the sockets code base. Of course, suitability for distributed systems was an important part of the 4.2BSD design brief and Rick Rashid was one of the steering committee members, that is all agreed. However in the code evolution for sockets I only see two influences that seem not direct continuations from earlier arpanet unices and have a possible Accent origins: - Addition of sendto()/recvfrom() to the API. Earlier code had poor support for UDP and was forced through the TCP focused API’s, with fixed endpoint addresses. It could be Accent inspired, it could also be a natural solution for sending datagrams. For example, Jack Haverty had hacked a “raw datagram” facility into UoI Arpanet Unix around ’79 (it’s in the Unix Tree). - Addition of a facility to pass file descriptors using sendmsg()/recvmsg() in the local domain. This facility was only added at the very last moment (it was not in 4.1c, only in 4.2). I’m being told that the CSRG team procrastinated on this because they did not see much use for it — and indeed it was mostly ignored in the field for the next two decades. Joy had left by that time, so perhaps the dynamics had changed. Earlier I though that the select() call may have come from Accent, but it was inspired by the Ada select statement. Conceptually, it was preceded on Unix by Haverty’s await() call (also ’79). For clarity: I wasn’t there, just commenting on what I see in the code. Paul

7 years, 1 month

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dead bstj unix link on wikipedia

by ron minnich

anyone got a fix? https://en.wikipedia.org/wiki/Bell_System_Technical_Journal see this text 1. Ritchie, D.M.; K. Thompson (July–August 1978). "The UNIX Time-Sharing System" <http://cm.bell-labs.com/cm/cs/who/dmr/cacm.html>. *Bell System Technical Journal*. *57* (6). Retrieved 2010-10-22

7 years, 1 month

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shared objects in Unix

by Paul Winalski

The recent discussion of long-lived applications, and backwards compatibility in Unix, got me thinking about the history of shared objects. My own experience with Linux and MacOS is that statically-linked applications tend to continue working from release to release, but shared objects provided by the OS tend not to be backwards compatible, and one often has to carry around with your application the exact C runtime and other shared objects your program was linked against. This is in big contrast to shared libraries on VMS, where great care is taken to maintain strict backward compatibility release to release. What is the history of shared objects on Unix? When did they first appear, and with what object/executable file format? The a.out ZMAGIC format doesn't seem to support them. I don't recall if COFF does. MACH-O, at least the MacOS dialect of it, supports dynamic libraries. ELF supports them. Also, when was symbol preemption invented? Traditional shared library designs such as in IBM System/370, VMS, and Windows NT doesn't have it. As one who worked on optimizations in compilers, I came to hate symbol preemption because it prohibits many useful optimizations. ELF does provide a way to turn it off, but it's on by default--you have to explicitly declare symbols as protected or hidden via source language pragmas to get rid of it. -Paul W.

7 years, 1 month

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Re: [TUHS] dead bstj unix link on wikipedia

by jnc＠mercury.lcs.mit.edu

> From: Ron Minnich > anyone got a fix? Google quickly shows that Dennis' home page is now at: https://www.bell-labs.com/usr/dmr/www/ >From there, the CACM paper (HTML form) is at: https://www.bell-labs.com/usr/dmr/www/cacm.html Noel

7 years, 1 month

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Novell, not SCO, found to own "Unix"

by Dave Horsfall

Time for another hand-grenade in the duck pond :-) Or as we call it down-under, "stirring the possum". On this day in 2010, it was found unanimously that Novell, not SCO, owned "Unix". SCO appealed later, and it was dismissed "with prejudice"; SCO shares plummeted as a result. As an aside, this was the first and only time that I was on IBM's side, and I still wonder whether M$ was bankrolling SCO in an effort to wipe Linux off the map; what sort of an idiot would take on IBM? -- Dave Horsfall DTM (VK2KFU) "Those who don't understand security will suffer."

7 years, 1 month

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The dollar symbol

by Dave Horsfall

On this day in 1778 businessman Oliver Pollock created the "$" sign, and now we see it everywhere: shell prompts and variables, macro strings, Perl variables, system references (SYS$BLAH, SWAP$SYS, etc), etc; where would we be without it? -- Dave Horsfall DTM (VK2KFU) "Those who don't understand security will suffer."

7 years, 1 month

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mail tuhs@minnie.tuhs.org

by Doug McIlroy

[TUHS] long lived programs (was Re: RIP John Backus > Every year someone takes some young hotshot and points them at some "impossible" thing and one of them makes it work. I don't see that changing. Case in point. We hired Tom Killian, a young high-energy physicist disenchanted with contributing to hundred-author papers. He'd done plenty of instrument programming, but no operating systems. So, high-energy as he was, he cooked up an exercise to get his feet wet. The result: /proc Doug

7 years, 1 month

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Re: [TUHS] RIP John Backus

by Paul McJones

On 3/17/2018 12:22 PM, Arthur Krewat <krewat(a)kilonet.net> wrote: > Leave it to IBM to do something backwards. > > Of course, that was in 1954, so I can't complain, it was 11 years before > I was born. But that's ... odd. > > Was subtraction easier than addition with digital electronics back then? > I would think that they were both the same level of effort (clock > cycles) so why do something obviously backwards logically? Subtraction was done by taking the two's complement and adding. I suspect the CPU architect (Gene Amdahl -- not exactly a dullard) intended programmers store array elements at increasing memory addresses, and reference an array element relative to the address of the last element plus one. This would allow a single index register (and there were only three) to be used as the index and the (decreasing) count. See the example on page 97 of: James A. Saxon Programming the IBM 7090: A Self-Instructional Programmed Manual Prentice-Hall, 1963 http://www.bitsavers.org/pdf/ibm/7090/books/Saxon_Programming_the_IBM_7090_… The Fortran compiler writers decided to reverse the layout of array elements so a Fortran subscript could be used directly in an index register.

7 years, 1 month

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daemons are not to be exorcised

by A. P. Garcia

Hi, The Hacker's Dictionary says that daemons were so named in CTSS. I'm guessing then that Ken Thompson brought them into Unix? I've noticed that more recent implementations of init have shunned the traditional terminology in favor of the more prosaic word "services". For example, Solaris now has SMF, the Service Management Facility, and systemd, the linux replacement for init, has services as well. It makes me a little sad, because it feels like some of the imaginativeness, fancifulness, and playfulness that imbue the Unix spirit are being lost.

7 years, 1 month

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Fwd: long lived programs (was Re: RIP John Backus

by Clem Cole

[try-II] On Fri, Mar 23, 2018 at 6:43 AM, Tim Bradshaw <tfb(a)tfeb.org> wrote: > On 22 Mar 2018, at 21:05, Bakul Shah <bakul(a)bitblocks.com> wrote: > > > I was thinking about a similar issue after reading Bradshaw's > message about FORTRAN programs being critical to his country's > security. What happens in 50-100 years when such programs have > been in use for a long time but none of the original authors > may be alive? The world may have moved on to newer languages > and there may be very few people who study "ancient" computer > languages and even they won't have in-depth experience to > understand the nuances & traps of these languages well enough. > No guarantee that FORTRAN will be in much use then! Will it be > like in science fiction where ancient spaceships continue > working but no one knows what to do when they break? > > > My experience of large systems like this is that this isn't how they work > at all. The program I deal with (which is around 5 million lines naively > (counting a lot of stuff which probably is not source but is in the source > tree)) is looked after by probably several hundred people. It's been > through several major changes in its essential guts and in the next ten > years or so it will be entirely replaced by a new version of itself to deal > with scaling problems inherent in the current implementation. We get a new > machine every few years onto which it needs to be ported, and those > machines have not all been just faster versions of the previous one, and > will probably never be so. > > What it doesn't do is to just sit there as some sacred artifact which > no-one understands, and it's unlikely ever to do so. The requirements for > it to become like that would be at least that the technology of large-scale > computers was entirely stable, compilers, libraries and operating systems > had become entirely stable and people had stopped caring about making it do > what it does better. None of those things seems very likely to me. > > (Just to be clear: this thing isn't simulating bombs: it's forecasting the > weather.) > +1 - exactly my point. We have drifted a bit from pure UNIX, but I actually do think this is relevant to UNIX history. Once UNIX started to run on systems targeting HPC loads where Fortran was the dominate programming language, UNIX quickly displaced custom OSs and became the dominant target even if at the beginning of that transition as the 'flavor' of UNIX did vary (we probably can and should discuss how that happened and why independently -- although I will point out the UNIX/Linux implementation running at say LLNL != the version running at say Nasa Moffitt). And the truth is today, for small experiments you probably run Fortran on Windows on your desktop. But for 'production' - the primary OS for Fortran is a UNIX flavor of some type and has been that way since the mid-1980s - really starting with the UNIX wars of that time. As I also have said here and elsewhere, while HPC and very much its lubricant, Fortran, are not something 'academic CS types' like to study these days - even though Fortran (HPC) pays my and many of our salar ies . Yet it runs on the system the those same academic types all prefer - *i.e.* Ken and Dennis' ideas. The primary difference is the type of program the users are running. But Ken and Dennis ideas work well for almost all users and spans specific application market s. Here is a picture I did a few years ago for a number of Intel exec's. At the time I was trying to explain to them that HPC is not a single style of application and also help them understand that there two types of value - the code itself and the data. Some markets ( *e.g.* Financial) use public data but the methods they use to crunch it ( *i.e.* the code s ) are private, while others market segments might have private data (*e.g.* oil and gas) but different customers use the same or similar codes to crunch it. F or this discussion, think about how much of the code I sho w below is complex arithmetics - while much of it is searching google style , but a lot is just plain nasty math. The 'nasty math' that has not changed over the years and thus those codes are dominated by Fortran. [Note Steve has pointed out that with AI maybe the math could change in the future - but certainly so far, history of these markets is basically differential equations solvers]. As Tim says, I really can not see that changing and the reason (I believe) is I do not see any compelling economic reason to do so. Clem ᐧ ᐧ

7 years, 1 month

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1978-03-25 - 2018-03-25: 40 years BSD Mail

by Steffen Nurpmeso

On this day in 1978 Kurt Shoens placed the following comment in def.h (the fork i maintain keeps it in nail.h): /* * Mail -- a mail program * * Author: Kurt Shoens (UCB) March 25, 1978 */ --steffen | |Der Kragenbaer, The moon bear, |der holt sich munter he cheerfully and one by one |einen nach dem anderen runter wa.ks himself off |(By Robert Gernhardt)

7 years, 2 months

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Re: [TUHS] long lived programs (was Re: RIP John Backus

by Doug McIlroy

"The only thing I can think of is to use have programs that translate programs in todays languages to a common but very simple universal language for their "long term storage". May be something like Lamport's TLA+? A very tough job. " Maybe not so hard. An existence proof is Brenda Baker's "struct", which was in v7. It converted Fortran to Ratfor (which of course turned it back to Fortran). Interestingly, authors found their completely reorganized code easier to read than what they had written in the first place. Her big discovery was a canonical form--it was not a matter of taste or choice how the code got rearranged. It would be harder to convert the code to say, Matlab, because then you'd have to unravel COMMON statements and format strings. It's easy to cook up nasty examples, like getting away with writing behyond the end of an array, but such things are rare in working code. Doug

7 years, 2 months

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Re: [TUHS] long lived programs

by Ron Natalie

A core package in a lot of the geospatial applications is a old piece of mathematical code originally written in Fortran (probably in the sixties). Someone probably in the 80's recoded the thing pretty much line for line (maintaining the horrendous F66 variable names etc.) into C. It's probably ripe for a jump to something else now. We've been through four major generations of the software. The original was all VAX based with specialized hardware (don't know what it was written in). We followed that on with a portable UNIX (but mostly Suns, but ours worked on SGI, Ardent, Stellar, various IBM AIX platofrms, Apollo DN1000's, HP, DEC Alphas). This was primarily a C application. Then right about the year 2000, we jumped to C++ on Windows. Subsequently it got back ported to Linux. Yes there are some modules that have been unchanged for decades, but the system on the whole has been maintained. The bigger issue than software getting obsoleted is that the platform needed to run it goes away.

7 years, 2 months

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Re: [TUHS] Comments in early Unix systems

by Doug McIlroy

Thanks for the noweb story. A reward for straying off topic! Doug

7 years, 2 months

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Re: [TUHS] daemons are not to be exorcised

by jnc＠mercury.lcs.mit.edu

> From: Larry McVoy <lm(a)mcvoy.com> > Going forward, I wish that people tried to be simple as they tackle the > more complicated problems we have. I have a couple of relevant quotations on my 'Some Computer-Related Lines' page: "Deliberate complexity is the mark of an amateur. Elegant simplicity is the mark of a master." -- Unknown, quoted by Robert A. Crawford "Fools ignore complexity. Pragmatists suffer it. Some can avoid it. Geniuses remove it." -- Alan Perlis "The most reliable components are the ones you leave out." -- Gordon Bell (For software, the latter needs to be read as 'The most bug-free lines of codqe are the ones you leave out', of course.) I remember watching the people building the LISP machine, and thinking 'Wow, that system is complex'. I eventually decided the problem was that they were _too_ smart. They could understand, and retain in their minds, all that complexity. Noel

7 years, 2 months

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Masscomp - Real Time Unix (RTU) an early UNIX based system, the first commercial multiprocessor and was realtime

by Clem Cole

On Wed, Mar 21, 2018 at 7:50 PM, Larry McVoy <lm(a)mcvoy.com> wrote: > I was sys admin for a Masscomp with a 40MB disk Right an early MC-500/DP system - although I think the minimum was a 20M [ST-506 based] disk. On Wed, Mar 21, 2018 at 8:55 PM, Mike Markowski <mike.ab3ap(a)gmail.com> wrote: > I remember Masscomp ... it allowed data acquisition to not be swapped >> out. >> > Actually, not quite right in how it worked, but in practice you got the desired behavior. More in a minute. On Wed, Mar 21, 2018 at 9:00 PM, Larry McVoy <lm(a)mcvoy.com> wrote: > I remember the Masscomps we had fondly. The ones we had were 68000 based > and they had two of those CPUs running in lock step Not lock step ... 'executor' and 'fixor' -- actually a solution Forest Basket proposed at Stanford. The two implementations that actually did this were the Masscomp MC-500 family and the original Apollo. > ... because the > 68K didn't do VM right. I can't remember the details, it was something > like they didn't handle faults right so they ran two CPUs and when the > fault happened the 2nd CPU somehow got involved. > Right, it the original 68000 did not save the faulting address properly when it took the exception, so there was not enough information to roll back the from the fault and restart. The microcode in the 68010 corrected this flaw. > > Clem, what model was that? We called the dual 68000 board the CPU board and the 68010/68000 board the MPU. The difference was which chip was in the 'executor' socket and some small changes in some PALs on the board to allow the 68010 to actually take the exception. Either way, the memory fault was processed by the 'fixor'. BTW: the original MC-500/DP was a dual processor system, so it has 4 68000 just for the 2 'cpu boards -- i.e. an executor and fixor on each board. The later MC-5000 family could handle up to 16 processor boards depending the model (MC-5000/300 was dual, MC-5000/500 up to 4 and the MC-5000/700 up to 16 processor boards). Also for the record, the MC-500/DP and MC-5000/700 predate the multiprocessor 'Symmetry System' that Sequent would produce by a number of years). The original RTU ran master/slave (Purdue VAX style) for the first generation (certainly through RT 2.x and maybe 3.x). That restriction was removed and a fully symmetric OS was created, as we did the 700 development. I've forgotten which OS release brought that out. A few years later Stellix, while not in direct source development a child, had the same Texieria/Cole team as RTU - was always fully symmetric - i.e. lesson learned. > And can you provide the real version of what I was trying say? > Sure ... soon after Motorola released the 68000, Stanford's Forest Baskett in a paper I have sadly lost, proposed that the solution the 68000's issue of not saving enough information when an illegal memory exception occured, was to instead of allowing the memory exception, return 'wait states' to the processor - thus never letting it fault. More specifically, the original microprocessor designs had a fixed time that the memory system needed to respond on a read or write cycle that was defined by the system clock. I don't have either Motorola 68000 or MOS 6502 processor books handy, but as a for instance IIRC on a 1 Mhz MOS 6502 you had 100 nS for this operation. Because EPROMs of the day could not respond that fast (IIRC 400ns for a read), the CPU chip designers created a special 'WAIT' signal that would tell the processor, to look for the data in on the next clock tick (and the wait signal could be repeated for each tick for an indefinite wait if need be). *i.e. *in effect, when running from ROM a 6502 would run at .25MHz if it was doing direct fetches from something like an Intel 1702 ROM on every cycle. Similarly, early dynamic RAM, while faster that ROM, had access issues with needing to ensure the refresh cycles and the access cycles aligned. Static RAMs which were fast, did not have these problems and could directly interface to processor, but static RAMs of the day were the quite expensive chips (5-10 times) in comparison to DRAM cost, so small caches were built to front end the memory system. Hence, the HW 'wait state' feature became standard (and I think is still supported in todays processors), since it allows the memory system speed and the processor to work at differing rates. i*.e.* the difference in speed could be 'biased' to each side -> processor vs memory. In his paper, Forest Basket observed that if a HW designer used the wait state feature, a memory system could be built that refreshed the cache using another processor, as long as the second processor that was 'fixing up' the exception ( i.e. refilled the cache with proper data) could be ensured it never had a memory fault. Basket's idea was exactly how both the original Apollo and Masscomp CPU boards were designed. On the Masscomp CPU board, there was a 68000 that always ran from a static ram based cache (which we called the 'executor.' If it tried to access a memory location that was not yet in cache, or if it was a legal memory access, the memory system sent wait states until the cache was refilled as you might expect. If the location was illegal, the memory system also return a error exception as expected. However, it was legal address but not yet in memory, the second 6800 (the 'fixor') was notified of desire to access that specific memory location and the fixor ran the paging code to put the page into the live memory. Once the cache was properly set up, then the executor could be released from wait state and instruction allowed to complete. When Motorola released the 68010 with the internal fixes that would allow an faulting instruction to be restarted, Masscomp revised the CPU board (creating the MPU board) to install a 68010 in the executor socket and changed a few PALs in the memory system on the board. If a memory address was discovered to be legal, but not in memory, the executor (now a 68010) was allowed to returned a paging exception and stack was saved appropriately, and the executor did a context switch to different process - allow the executor to do something useful while the fixor processed the fault. Although we now had to add kernel code for the executor processor to return from restart at the fault instruction on a context switch back to the original process. The original fixor code did not need to be changed, other than to remove need to clearing of the 'waiting flop' for that restarted the executor. [RTU would detect which board was plugged into a specific system automatically so it was an invisible change to the end user - other than you got a few percent performance back if there was a lot of page faults in your application since the executor never wait stated]. As for the way real time and analog I/O worked that Mike commented upon. Yes, RTU - Real Time Unix supported features that could guarantee that I/O would not be lost from the DMA front end. For those not familiar with the system, it was a 'federated system' with a number of subsystems: the primary UNIX portion that I just described and then a number of other specialized processors that surrounded it for specific tasks. This architecture was chosen because the market we were attacking was a scientific laboratory and in particular real-time oriented - for instance, some uses were Mass General in the Cardiac ward, on board ever EWACS plane to collect all and retain all signals during any sortie [very interesting application], NASA used 75 of them in Mission Control to be the 'consoles' you see on TV, *etc *[ which have only recently be replaced by PCs, as some were still in use at least 2 years ago when I was last in Houston]. So besides the 2/4 68000s in the main UNIX system, their was another dedicated 68000 running a graphics system on the graphics board, another 80186 running TCP/IP, and an AM2900 bit slices processor called Data Acquisition and Control Processor (DA/CP) - which Mike hinted, as well as 29000's for the FP unit and Array processor functionality. Using ther DA/CP, in 1984, and MC-500 system could handle multiple 1MHz analog 16 bit signals - just by sampling them -> in fact, a cute demo at the Computer Museum in Boston just connected a TV camera to the DA/CP and without any special HW, it could 'read' the video signal (if you normally have a connection a TV camera, it usually takes a bunch of special logic to interface to the TV signals -- in this case it was just SW in the DA/CP). The resultant OS was RTU, were we had modified a combined 4.1BSD and System III 'unices' (later up dated to 4.2 and V.2] to support RT behaviors, with pre-emption, ASTs [which I still miss - a great idea but nicer than traditional UNIX signals], async I/O, *etc*.. Another interesting idea was the concept of 'universes' that allowed on a per user basis, to see a BSD view of the system or an System V view]. One of the important things we did in RTU was rethink the file system (although only a little then). Besides all the file types and storage schemes you have with UFS, Masscomp added support for an pre-allocated extent based files (like VMS and RSX) and then created a new file type called contiguous file that used it [by the time of the Stellar and Stellix, we just made all files extent based and got rid of the special file type - *i.e.* looked like UFS to the user, but under the covers was fully extend based]. So under RTU, once we had preallocated files that we knew were on contiguous blocks, we could make all sorts of speed ups and guarantees that traditional UNIX can not because of the randomized location of the disk blocks. So the feature that Mike was using, was actually less a UNIX change and did not actually use the preemption and other types of RT features. We had added the ability for the DA/CP to write/read information directly from the disk without OS getting in the way - (we called it Direct to Disk IO). An RTU application created a contiguous file large enough on disk to store the data the DA/CP might receive - many megabytes typically - but the data itself was never passed thru or stored in the UNIX buffer cache *etc*. The microcode of the DA/CP and the RTU disk driver could/would cooperate and all kernel or user processing on the UNIX side was by-passed. Thus, when the real time data started to be produced by the DA/CP (say the EWACS started getting radio signals on one of those 16 bit analog converters) the digital representation of those analog signals were stored in the users file system independent of what RTU was doing. The same idea, by the way was why we chose to run IP/TCP on a co-processor. So much of network I/O is 'unexpected,' we could potentially lose the ability to make real-time guarantees. But keeping all the protocol work outside of UNIX, the network I/O just operated on 'final bits' at the rate that was right for it. As an interesting aside, this worked until we switched to a Motorola 68020 at 16 Mhz or 20Mhz (whatever it was I've forgotten now) in the MC-5000 system. The host ended up be so much faster than the 80186 in the ethernet coprocessor board. We ended up offering a mode were they swapping roles and just used the '186 board as a very heavily buffered ethernet controller, so we could keep protocol processing very low priority compared to other tasks. However if we did that, it did mean some of the system guarantees had to be removed. My recollection is that only a couple of die hard RT style customers, ended up continuing to use the original networking configuration. Clem

7 years, 2 months

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daemons are not to be exorcised/Comments in code

by David

> From: Dave Horsfall <dave(a)horsfall.org> > Yep, and I'm glad that I had bosses to whom I didn't have to explain why > my comments were so voluminous. > > And who first said "Write your code as though the next person to maintain > it is a psychotic axe-wielding murderer who knows where you live"? I've > often thought that way (as the murderer I mean, not the murderee). > > I'd name names, but he might be on this list... > I’ve always said that the person was a ‘reformed’ axe-wielding murderer who knows where you live. Please, a little decorum. W.R.T. comments in code, and a bit of Unix, when I taught Unix Systems programming at UCSD one of my students wanted to use his personal computer for the programming. I didn’t care as long as it would pass the tests I ran after the fact. After his second homework was turned in, I stopped looking at his code or even running it, as the comment blocks were just so well done. Nary a comment in the function itself, just a block before each one very clearly explaining what was happening. David

7 years, 2 months

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Re: [TUHS] Comments in early Unix systems

by Doug McIlroy

"I was told in school (in 1985) that if I was ever lucky enough to have access to the unix source, I'd find there were no comments. The reason, I was told at the time, was that comments would make the source code useful, and selling software was something AT&T couldn't do due to some consent decree." I can't speak for SYS V, but no such idea was ever mentioned in Research circles. Aside from copyright notices, the licensing folks took no interest in comments. Within rsearch there was tacit recognition of good coding style--Ken's cut-to-the-bone code was universally admired. This cultural understanding did not extend to comments. There was disparagement for the bad, but not honor for the good. Whatever comments you find in the code were put there at the author's whim. My own commenting style is consistent within a project, but wildly inconsistent across projects, and not well correlated with my perception of the audience I might be writing for. Why? I'm still groping for the answer. For imoortant code, custom is to describe it in a separate paper, which is of course not maintained in parallel with the code. In fact, comments are often out of date, too. Knuth offered the remedy of "literate programming", which might help in academic circles. In business, probably not. Yet think of the possibility of a "literate spec", where the code grows organically with the understanding of what has to be done. Doug

7 years, 2 months

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Re: [TUHS] Comments in early Unix systems

by jnc＠mercury.lcs.mit.edu

> From: Warren Toomey <wkt(a)tuhs.org> > there is next to no commenting in the early code bases. By 'early' you must mean the first 'C' PDP-11 Unixes, because certainly starting with V6, it is reasonably well commented (to the point where I like to say that I learned how to comment by reading the V6 code), e.g.: http://minnie.tuhs.org/cgi-bin/utree.pl?file=V6/usr/sys/ken/slp.c http://minnie.tuhs.org/cgi-bin/utree.pl?file=V6/usr/sys/dmr/bio.c to pick examples from each author; and there are _some_ comments in the assembler systems (both PDP-7 and PDP-11). > Given that the comments never made it into the compiled code, there was > no space reason to omit comments. There must have been another reason. I was going to say 'the early disks were really small', but that hypothesis fails because the very earliest versions (in assembler) do have some comments. Although assembler is often so cryptic, the habit of putting a comment on each instruction isn't so unreasonable. So maybe the sort of comments one sees in assembler code (line-by-line descriptions of what's happening; for subroutines, which arguments are in which registers; etc) aren't needed in C code, and it took a while for them to work out what sort of commenting _was_ appropriate/useful for C code? The sudden appearance in V6 does make it seem as if there was a deliberate decision to comment the code, and they went through it and added them in a deliberate campaign. > From: Andy Kosela <akosela(a)andykosela.com> > "Practice of Programming" by Rob Pike and Brian Kernighan. > ... > They also state: "Comments ... do not help by saying things the code > already plainly says ... The best comments aid ... by briefly pointing > out salient details or by providing a larger-scale view of the > proceedings." Exactly. Noel

7 years, 2 months

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Happy 25th Birthday NetBSD!

by Jeremy C. Reed

Revision 1.1, Sun Mar 21 09:45:37 1993 UTC (25 years ago) by cgd http://cvsweb.netbsd.org/bsdweb.cgi/src/sbin/init/init.c?rev=1.1&content-ty… Today is commonly considered the birthday of NetBSD. Theo told me (seven years ago) that he, cgd, and glass (and one other person) planned it within 30 minutes after discussing with the CSRG and BSDI guys in the hot tub at the Town & Country Resort in San Diego at the January 25-29 1993 USENIX conference. (Does anyone have more to share about this discussion?) Soon, cgd had setup a CVS repository (forked 386BSD with many patchkits) which was re-rolled a few times (due to corrupted CVS). (So maybe March 21 is later than the real birthday.) As far as I know, it is the oldest continuously-maintained complete open source operating system. (It predates Slackware Linux, FreeBSD, and Debian Linux by some months.) "NetBSD" wasn't mentioned by name in the April 19. 1993 release files (but was named in the announcement). ftp://ftp.netbsd.org/pub/NetBSD/misc/release/NetBSD/NetBSD-0.8 On April 28, the kernel was renamed to /netbsd, the boot loader identified it as NetBSD, and various references of 386BSD were changed to NetBSD. https://github.com/NetBSD/src/commit/a477732ff85d5557eef2808b5cbf221f3c7455… https://github.com/NetBSD/src/commit/446115f2d63299e52f34977fb4a88c289dcae9…

7 years, 2 months

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Re: [TUHS] FORTRAN

by Johnny Billquist

On 2018-03-21 14:48, Paul Winalski<paul.winalski(a)gmail.com> wrote: > > On 3/20/18, Clem Cole<clemc(a)ccc.com> wrote: >> Paul can correct me, but I don't think DEC even developed a Pascal for TOPS >> originally - IIRC the one I used came from the universities. I think the >> first Pascal sold was targeted for the VAX. Also, RT11 and RSX were >> 'laboratory' systems and those systems were dominated by Fortran back in >> the day - so DEC marketing thought in those terms. >> > DEC did do a Pascal for RSX. I don't remember if it supported RT11 or > RSTS. DEC did a BASIC compiler for RSTS and RSX. RSX and especially > RT were designed mainly for real-time process control in laboratories. DEC did both COBOL, DIBOL, PASCAL, FORTRAN (-IV, -IV-PLUS, -77), C as well as Datatrieve for RSX and RSTS/E. Some of these were also available for RT-11. Admittedly, the C compiler was very late to the game. > A lot of the programming was in assembler for efficiency reasons > (both time and space). Yes. And MACRO-11 is pretty nice. Johnny -- Johnny Billquist || "I'm on a bus || on a psychedelic trip email: bqt(a)softjar.se || Reading murder books pdp is alive! || tryin' to stay hip" - B. Idol

7 years, 2 months

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Happy birthday, PDP-8!

by Dave Horsfall

Let's see how much this thread can drift... The venerable PDP-8 was introduced in 1965 today (or tomorrow if you're on the wrong side of the date line). It was the first computer I ever used, back around 1970 (I think I'd just left school and was checking out the local University's computer department, and played with BASIC and FOCAL). And (hopefully) coincidentally the Pentium first shipped in 1993; the infamous FDIV defect was discovered a year later (and it turned out that Intel was made aware of it by a post-grad student a bit earlier), and what followed next was an utter farce, with some dealers refusing to accept the results of a widely-distributed program as evidence of a faulty FPU. -- Dave Horsfall DTM (VK2KFU) "Those who don't understand security will suffer."

7 years, 2 months

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Re: [TUHS] FORTRAN

by jnc＠mercury.lcs.mit.edu

> From: "Steve Johnson" So, I have this persistent memory that I read, in some early Multics (possibly CTSS, but ISTR it was Multics) document, a footnote explaining the origin of the term 'daemon'. I went looking for it, but couldn't find it in a 'quick' scan. I did find this, though, which is of some interest: R. A. Freiburghouse, "The Multics PL/1 Compiler" (available online here: http://multicians.org/pl1-raf.html if anyone is interested). > There was a group that was pushing the adoption of PL/1, being used to > code Multics, but the compiler was late and not very good and it never > really caught on. So, in that I read: The entire compiler and the Multics operating system were written in EPL, a large subset of PL/1 ... The EPL compiler was built by a team headed by M. D. McIlroy and R. Morris ... Several members of the Multics PL/1 project modified the original EPL compiler to improve its object code performance, and utilized the knowledge acquired from this experience in the design of the Multics PL/1 compiler. The EPL compiler was written when the _original_ PL/1 compiler (supposedly being produced by a consulting company, Digitek) blew up. More detail is available here: http://multicians.org/pl1.html I assume it's the Digitek compiler you were thinking of above? Noel

7 years, 2 months

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RIP John Backus

by Dave Horsfall

We lost computer pioneer John Backus on this day in 2007; amongst other things he gave us FORTRAN (yuck!) and BNF, which is ironic, really, because FORTRAN has no syntax to speak of. -- Dave Horsfall DTM (VK2KFU) "Those who don't understand security will suffer."

7 years, 2 months

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Timelines of 15, 596 documented Unix facilities from 1970 until today

by Diomidis Spinellis

I've put online at https://dspinellis.github.io/unix-history-man/ nine timelines detailing the evolution of 15,596 unique documented facilities (commands, system calls, library functions, device drivers, etc.) across 93 major Unix releases tracked by the Unix history repository. For each facility you get a timeline starting from the release it first appeared. Clicking on the timeline opens up the manual page for the corresponding release. (Sadly, the formatting is often messed up, because more work is needed on the JavaScript troff renderer I'm using.) The associated scripts and the raw data are all available on GitHub. Diomidis

7 years, 2 months

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mt Xinu Unix manuals

by Deborah Scherrer

A while ago someone was asking about the mt Xinu Unix manuals. I have a found a complete set, currently owned by Vance Vaughan, one of the mt Xinu founders. He is willing to donate them to Warren's Unix archive. However, they are too expensive to ship to Australia. Would anyone be willing to scan them in for the archive? Ah, there are a lot of them (8? volumes). If so, I might be able to ship them to somewhere in the US. Let me know. Thanks. Deborah

7 years, 2 months

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Re: [TUHS] daemons are not to be exorcised

by Nelson H. F. Beebe

Peter Guthrie Tait (1831--1901) seems to have recorded the oldest mention of the thermodynamic demon of James {Clerk Maxwell} in the page 213 image from Tait's book ``Sketch of Thermodynamics'' at https://archive.org/stream/lifescientificwo00knotuoft#page/212/mode/2up that was posted to this list by Bakul Shah <bakul(a)bitblocks.com> on Tue, 20 Mar 2018 12:10:37 -0700. I've been working on a bibliography (still unreleased) of Clerk Maxwell, and the oldest reference that I had so far found to Maxwell's demon is from an address by Sir William Thomson (later raised to Lord Kelvin) entitled The sorting demon of Maxwell: [Abstract of a Friday evening Lecture before the Royal Institution of Great Britain, February 28, 1879] Proceedings of the Royal Institution of Great Britain 9, 113--114 (1882) However, I've not been able to find that volume online. Hathi Trust has only volumes 30--71, with numerous holes, and often, it will not show page contents at all. The journal issue is old enough that few university libraries are likely to have it, but it is probably available through the Interlibrary Loan service. I had also recorded Harold Whiting Maxwell's demons Science (new series) 6(130), 83, July 1885 https://doi.org/10.1126/science.ns-6.130.83 and W. Ehrenberg Maxwell's demon Scientific American 217(5) 103--110, November 1967 https://doi.org/10.1038/scientificamerican1167-103 plus numerous later papers and books. I also went through a score of books on my shelf about physics or thermodynamics, and finally found a brief mention of Maxwell's demon in G. N. Lewis & M. Randall's famous text ``Thermodynamics'', first published in 1923 (I have a 1961 reprint). The other books that I checked remain strangely silent on that topic. The Oxford English Dictionary (OED) online has this definition and etymology: >> ... >> Maxwell's demon n. (also Maxwell demon) an entity imagined by Maxwell >> as allowing only fast-moving molecules to pass through a hole in one >> direction and only slow-moving ones in the other direction, so that if >> the hole is in a partition dividing a gas-filled vessel, one side >> becomes warmer and the other cooler, in contradiction of the second >> law of thermodynamics. >> >> 1879 W. Thomson in Proc. Royal Inst. 9 113 Clerk Maxwell's `demon' is >> a creature of imagination.., invented to help us to understand the >> `Dissipation of Energy' in nature. >> >> 1885 Science 31 July 83/1 (heading) Maxwell's demons. >> >> 1956 E. H. Hutten Lang. Mod. Physics iv. 152 It would require a >> Maxwell demon..to select the rapidly moving molecules according to >> their velocity and concentrate them in one corner of the vessel. >> >> 1971 Sci. Amer. Sept. 182/2 Maxwell's demon became an intellectual >> thorn in the side of thermodynamicists for almost a century. The >> challenge to the second law of thermodynamics was this: Is the >> principle of the increase of entropy in all spontaneous processes >> invalid where intelligence intervenes? >> >> 1988 Nature 27 Oct. 779/2 Questions about the energy needed in >> measurement began with Maxwell's demon. >> ... For the word `daemon', the OED has this: >> ... >> Etymology: Probably an extended use of demon .... >> >> A program (or part of a program), esp. within a Unix system, which >> runs in the background without intervention by the user, either >> continuously or only when automatically activated by a particular >> event or condition. A distinction is sometimes made between the form >> daemon, referring to a program on an operating system, and demon, >> referring to a portion of a program, but the forms seem generally to >> be used interchangeably, daemon being more usual. >> >> 1971 A. Bhushan Request for Comments (Network Working Group) >> (Electronic text) No. 114. 2 The cooperating processes may be >> `daemon' processes which `listen' to agreed-upon sockets, and >> follow the initial connection protocol. >> >> 1983 E. S. Raymond Hacker's Dict. 53 The printer daemon is just a >> program that is always running; it checks the special directory >> periodically, and whenever it finds a file there it prints it >> and then deletes it. >> >> 1989 DesignCenter ii. 41/3 The file server runs a standard set of >> HP-UX system and network daemons. >> >> 1992 New Scientist 18 Jan. 35/2 These programs, which could recognise >> simple patterns, were made up of several independent >> information-processing units, or `demons', and a `master >> demon'. >> >> 2002 N.Y. Times 7 Mar. d4/5 A mailer daemon installed on an e-mail >> system can respond to a piece of incorrectly addressed e-mail >> by generating an automated message to the sender that the >> message was undeliverable. >> ... ---------------------------------------- >From The Hacker's Dictionary (1983), reproduced in the Emacs info node Jargon, I find another `explanation' of daemon: >> ... >> :daemon: /day'mn/ or /dee'mn/ /n./ [from the mythological >> meaning, later rationalized as the acronym `Disk And Execution >> MONitor'] A program that is not invoked explicitly, but lies >> dormant waiting for some condition(s) to occur. The idea is that >> the perpetrator of the condition need not be aware that a daemon is >> lurking (though often a program will commit an action only because >> it knows that it will implicitly invoke a daemon). For example, >> under {{ITS}} writing a file on the {LPT} spooler's directory >> would invoke the spooling daemon, which would then print the file. >> The advantage is that programs wanting (in this example) files >> printed need neither compete for access to nor understand any >> idiosyncrasies of the {LPT}. They simply enter their implicit >> requests and let the daemon decide what to do with them. Daemons >> are usually spawned automatically by the system, and may either >> live forever or be regenerated at intervals. >> >> Daemon and {demon} are often used interchangeably, but seem to >> have distinct connotations. The term `daemon' was introduced to >> computing by {CTSS} people (who pronounced it /dee'mon/) and >> used it to refer to what ITS called a {dragon}. Although the >> meaning and the pronunciation have drifted, we think this glossary >> reflects current (1996) usage. >> ... ------------------------------------------------------------------------------- - Nelson H. F. Beebe Tel: +1 801 581 5254 - - University of Utah FAX: +1 801 581 4148 - - Department of Mathematics, 110 LCB Internet e-mail: beebe(a)math.utah.edu - - 155 S 1400 E RM 233 beebe(a)acm.org beebe(a)computer.org - - Salt Lake City, UT 84112-0090, USA URL: http://www.math.utah.edu/~beebe/ - -------------------------------------------------------------------------------

7 years, 2 months

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Re: [TUHS] PDP-11 DIV instruction lossage

by jnc＠mercury.lcs.mit.edu

> I'll have to redo my kludgy fix to gmtime() ... I guess I'll have to fix > it for real, instead of my kludgy fix (which extended it to work for > 16-bit results). :-) > ... > And on the -11/23: > Note that the returned 'quotient' is simply the high part of the dividend. Heh. I had decided that the easiest clean and long-lived fix was to just to do it right, using the long division routine used in the V7 C compiler runtime: http://minnie.tuhs.org/cgi-bin/utree.pl?file=V7/usr/src/libc/crt/ldiv.s and I vaguely recalled reading a DMR story that talked about that, so just for amusement I decided to re-read it, and looked it up: https://www.bell-labs.com/usr/dmr/www/odd.html (the section "Comments I do feel guilty about"), and it's lucky I did, because I found this: Addendum 18 Oct 1998 Amos Shapir of nSOF (and of long memory!) just blackened (or widened) the spot a bit more in a mail message, to wit: 'I gather the "almost" here is because this trick almost worked... It has a nasty bug which I had to find the hard way! The "clever part" relies on the fact that if the "bvc 1f" is not taken, it means that the result could not fit in 16 bits; in that case the long value in r0,r1 is left unchanged. The bug is that this behavior is not documented; in later models (I found this on an 11/34) when the result does fit in 16 bits but not in 15 bits ... which makes this routine provide very strange results!' So this code won't work on an 11/23 either (which bashes the low register of the pair; above). I'd have been groveling in buggy math, again... Caveat Haquur (if you're trying to run stock V7 on a /23 or /34)! Noel

7 years, 2 months

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PDP-11 DIV instruction lossage

by jnc＠mercury.lcs.mit.edu

So, I have discovered, to my astonishment, that the double-word version of the DIV instruction on the PDP-11 won't do a divide if the result won't fit into 15 bits. OK, I can understand it bitching if the quotient wouldn't fit into 16 bits - but what's the problem with returning an unsigned quotient? And, just for grins, the results left in the registers which hold the quotient and remainer is different in the -11/23 (KDF11-A) and the -11/73 (KDJ11-A). (Although, to be fair, the PDP-11 Architecture Manual says 'register contents are unpredictable if there's an overflow'.) Oh well, guess I'll have to redo my kludgy fix to gmtime() (the distributed version of which in V6 qhas a problem when the number of 8-hour periods since the epoch overflows 15 bits)! I guess I'll have to fix it for real, instead of my kludgy fix (which extended it to work for 16-bit results). :-) I discovered this when I plugged in an -11/73 to make sure the prototype QSIC (our RK11/etc emulator for the QBUS) worked with the -11/73 as well as the -11/23 (which is what we'd mostly been using - when we first started working on the DMA and interrupts, we did try them both). I noticed that with the -11/73, the date printed incorrectly: Sun Mar 10 93:71:92 EST 1991 After a certain amount of poking and prodding, I discovered the issue - and on further reading, discovered the limitation to 15-bit results. For those who are interested in the details, here's a little test program that displays the problem: r = ldiv(a, b, d); m = ldivr; printf("a: 0%o %d. b: 0%o %d. d: 0%o %d.\n", a, a, b, b, d, d); printf("q: 0%o %d. r: 0%o %d.\n", r, r, m, m); and, for those who don't have V6 source at hand, here's ldiv(): mov 2(sp),r0 mov 4(sp),r1 div 6(sp),r0 mov r1,_ldivr rts pc So here are the results, first from a simulator: tld 055256 0145510 070200 a: 055256 23214. b: 0145510 -13496. d: 070200 28800. q: 0147132 -12710. r: 037110 15944. This is _mathematically_ correct: 055256,0145510 = 1521404744., 070200 = 28800., and 1521404744./28800. = 0147132. And on the -11/23: a: 055256 23214. b: 0145510 -13496. d: 070200 28800. q: 055256 23214. r: 037110 15944. Note that the returned 'quotient' is simply the high part of the dividend. And on the -11/73: a: 055256 23214. b: 0145510 -13496. d: 070200 28800. q: 055256 23214. r: 037110 15944. Note that in addition to the quotient behaviour, as with the /23, the 'remainder' is the low part of the dividend. Noel

7 years, 2 months

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Re: [TUHS] RIP John Backus

by jnc＠mercury.lcs.mit.edu

> From: Paul McJones <paul(a)mcjones.org> > I suspect the CPU architect (Gene Amdahl -- not exactly a dullard) > intended programmers store array elements at increasing memory > addresses, and reference an array element relative to the address of the > last element plus one. This would allow a single index register (and > there were only three) to be used as the index and the (decreasing) > count. I suspect the younger members of the list, who've only ever lived in a world in which one lights ones cigars with mega-gates, so to speak, may be missing the implication here. Back when the 704 (a _tube_ machine) was built, a register meant a whole row of tubes. That's why early machines had few/one register(s). So being able to double up on what a register did like this was _HYYUUGE_. Noel

7 years, 2 months

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Re: [TUHS] RIP John Backus

by Paul McJones

On 3/17/2018 8:54 AM, Dave Horsfall <dave(a)horsfall.org> wrote: > ... Was it the 704, or the 709? I recall that the > array indexing order mapped directly into its index register or something > ... It first ran on the IBM 704, whose index registers subtracted (as did the follow-on 709, 7090, etc), so array indexing went from higher memory addresses to lower. > The bookshelf: I had most of those books once; what's the one on the > bottom right? It has a "paperback" look about it, but I can't quite make > it out because of the reflection on the spine. I'm not sure, and things have shifted since then on the shelves, but I sent the original photo to your email address.

7 years, 2 months

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Re: [TUHS] RIP John Backus

by Paul McJones

On 3/17/2018 12:22 PM, Steve Simon <steve(a)quintile.net> wrote: > on the subject of fortran’s language, i remember hearing tell of a French version. anyone ever meet any? Yes: here is the French version of the original Fortran manual, with keywords in French (via http://www.softwarepreservation.org/projects/FORTRAN/) Anonymous. FORTRAN Programmation Automatique de L'Ordinateur IBM 704 : Manuel du Programmeur. IBM France, Institut de Calcul Scientifique, Paris. No date, 51 pages. Given to Paul McJones by John Backus. http://archive.computerhistory.org/resources/text/Fortran/102663111.05.01.a…

7 years, 2 months

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Re: [TUHS] RIP John Backus

by Paul McJones

Dave Horsfall <dave(a)horsfall.org> wrote: > We lost computer pioneer John Backus on this day in 2007; amongst other > things he gave us FORTRAN (yuck!) and BNF, which is ironic, really, > because FORTRAN has no syntax to speak of. I think of FORTRAN as having established the very idea of high-level programming languages. For example, John McCarthy’s first idea for what became LISP was to extend FORTRAN with function subroutines written in assembly language for list-manipulation. (He had to give up on this idea when he realized a conditional expression operator wouldn’t work correctly since both the then-expression and the else-expression would be evaluated before the condition was tested.) The original FORTRAN compiler pioneered code optimization, generating code good enough for the users at the physics labs and aerospace companies. For more on this compiler, see: http://www.softwarepreservation.org/projects/FORTRAN/ Disclosure: I worked with John in the 1970s (on functional programming) — see: http://www.mcjones.org/dustydecks/archives/2007/04/01/60/ . Paul McJones

7 years, 2 months

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Happy birthday, symbolics.com!

by Dave Horsfall

The first Internet domain, symbolics.com, was registered in 1985 at 0500Z ("Zulu" time, i.e. UTC). -- Dave Horsfall DTM (VK2KFU) "Those who don't understand security will suffer."

7 years, 2 months

10
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Re: [TUHS] Origin of the MOTD file?

by Doug McIlroy

> So what are its origins? Where did it first appear? It was a direct copy from CTSS, which already had it n 1965 when we BTL folk began to use it. The greatest MOTD story of all time happened at CTSS. To set the stage, the CTSS editor made a temp file, always of the same name, in one's home directory. The MOTD was posted by the administrator account. The password file was plain text, maintained by editing it. And multiple people had access to the administrator account. It happened one day that one administrator was working on the password file at the same time another was posting MOTD. The result: the password file (probably the most secret file on the system) got posted as the MOTD (the most public). Upon seeing the password file type out before him, an alert user shut the machine down by writing and running one line of assembly code: HERE TRA *HERE (The star is for indirect addressing, and indirection was transitive.) Doug

7 years, 2 months

2
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Origin of the MOTD file?

by Dan Cross

One of the things that's always fascinated me about Unix is the community aspect; in particular, I imagine that in the early days when machines were multiplexed among many simultaneous users, I wonder whether there was a greater sense of knowing what others were up to, working on, or generally doing. I think of the /etc/motd file as being a part of this. It is, in some very real sense, a way to announce things to the entire user community. So what are its origins? Where did it first appear? I haven't dug into this, but I imagine it was at Berkeley. What was it used for early on at individual sites? - Dan C.

7 years, 2 months

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Re: [TUHS] Happy birthday, symbolics.com!

by jnc＠mercury.lcs.mit.edu

> From: Dave Horsfall > he would've been the registraNT, no? Symbolics was the registrant. I may have spoken too soon, Postel/ISI might not have been the registrar when ".com" was set up, so maybe it was someone at SRI/NIC. (The memory is dim.) I don't remember how "MIT.EDU" got registered - I'm not sure if I did it. It was definitely Jon handing out addresses, not SRI - I do recall us going to Jon to get 128.30 & 31. Noel

7 years, 2 months

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Re: [TUHS] Happy birthday, symbolics.com!

by jnc＠mercury.lcs.mit.edu

> From: Michael Kjörling > the DNS RFCs (initially 1034, 1035) were only published in 1987... Ah, those were later versions; the originals were: 0882 Domain names: Concepts and facilities. P.V. Mockapetris. November 1983. 0883 Domain names: Implementation specification. P.V. Mockapetris. November 1983. Both were updated by RFC0973 before being replaced by 1034/1035. You might also want to look at: 0881 Domain names plan and schedule. J. Postel. November 1983. 0897 Domain name system implementation schedule. J. Postel. February 1984. 0921 Domain name system implementation schedule - revised. J. Postel. October 1984. Note that ".com" didn't exist in the early revs. Noel

7 years, 2 months

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Re: [TUHS] Happy birthday, symbolics.com!

by jnc＠mercury.lcs.mit.edu

> From: Pete Wright > who was the registrar that they used to register this domain? Postel (or one of his minions). Noel

7 years, 2 months

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Re: [TUHS] Illinois PDP-11 Network Unix

by jnc＠mercury.lcs.mit.edu

> From: Lars Brinkhoff > Is this "Network Unix" available? ??? This was announced here not long ago: http://minnie.tuhs.org/cgi-bin/utree.pl?file=SRI-NOSC It's called 'NOSC' because that's where it came from, but it has the Illinois NCP code in it. Noel

7 years, 2 months

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Illinois PDP-11 Network Unix

by Lars Brinkhoff

Hello, Is this "Network Unix" available? https://www.ideals.illinois.edu/bitstream/handle/2142/32817/networkunixsyst… https://tools.ietf.org/html/rfc681 Or, is there another Unix which will do pre-TCP/IP Arpanet? I have an off-topic system with NCP, but no one to talk to.

7 years, 2 months

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nix/Linux friendly hardware free of proprietary software

by iPwn iPwn

7 years, 2 months

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Unix friendly hardware free of proprietary software

by iPwn iPwn

hi, im looking for Unix/Unix-like/Linux friendly hardware(desks,laps,phones,etc) free of proprietary software or compatible with free software(OS,BIOS firmware,etc) something that is easy to replace stock or something that cames with free software preinstalled and that i can replace them if i want to. i've seen some lists that contain vendors that are Unix/Linux friendly and also the hardware endorsed by FSF which seem to be Lenovo thinkpads,etc the thing is it seems most of hardware require external flashing to replace BIOS,etc and makes the task harder.. my question are, what are the bests Unix/Unix-like/Linux friendly hardware manufacturers? which hardware is the best to make a computer 100% free (free BIOS and OS) and that is optimized and behave better under Unix/Unix-like/Linux based OS's? Thank you. -- PHACT Phreakers / Hackers / Anarchists / Cyberpunks / Technologists

7 years, 2 months

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Sleep()y musings

by Dave Horsfall

Back when the dinosaurs were using card readers (and yes, I've used a card reader on Unix; I think it was a desktop CDC model, and the driver would handle two modes: strict 80-column i.e. one 12-bit column per 16-bit word and you got 80 of 'em on a DMA channel, or ASCII NL-terminated after last non-blank column, and no, I have no idea whether it handled EBCDIC or CDC etc, but I digress as usual). Where was I? Oh yes, sleeps... Back when sleep(3) was sleep(2) (yes, Virginia, sleep() used to be a system call, then it became alarm()/pause(), and now it seems to be nanosleep(), and I'm wandering again), you never called sleep(1) because its granularity was +/-1 second (and all the way up to +infinity, actually, on a really busy machine), thus it could return right away, with ensuing hilarity. So, I'm curious: When did sleep(2) become sleep(3)? Was it V7, or some BSD? Or Babbage help me, SysVile? When did the caveat about sleeping for 1 second become known? I don't think that I ever saw it documented, but was one of those "lore" things passed around at Unix conferences and the like. And when did it start using nanosleep() instead of alarm()/pause()? I see that my Penguin box has a bet both ways; it "may" use SIGALRM[a] (thus "mixing calls to alarm(2) and sleep() is a bad idea" (well, I've used both), and also refers to nanosleep(). [a] Alpine's spell-checker suggested "SICKROOM" here; pretty close when dealing with timed-out reads on a TTY connection[ii] :-) [ii] Have you tried this with Perl? You can't rely on EINTR[3], so you have to use eval{} blocks instead, and it starts getting pretty fugly... [3] And here it suggested "ENTREE". -- Dave Horsfall DTM (VK2KFU) "Those who don't understand security will suffer."

7 years, 2 months

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Re: [TUHS] Sleep()y musings

by Rudi Blom

>Date: Wed, 7 Mar 2018 13:54:32 -0500 >From: Paul Winalski <paul.winalski(a)gmail.com> >To: Clem Cole <clemc(a)ccc.com> >Cc: The Eunuchs Hysterical Society <tuhs(a)tuhs.org> >Subject: Re: [TUHS] Sleep()y musings >Message-ID: > <CABH=_VTO7sdgGypp3U7zQoWdJ3HsGUUjrk->6_Rf5VE5gyNGD7g(a)mail.gmail.com> >Content-Type: text/plain; charset="UTF-8" > >... >VAX also has a Time-of-Year Clock Register (colloquially called the >TOY clock), a 32-bit unsigned value whose LSB represents a resolution >of 10 milliseconds (0.01 second). All VAX models except the >VAX-11/730 provided battery backup for the TOY clock so that it >continued to operate even when the system was powered off. A VAX can >thus be powered off for about 497 days and still remember the >date/time. Also in AlphaServers we still have this TOY, the clock and the battery that is. >From a DS10 running Digital Unix 4.0G, /var/adm/messages file, I only removed the BEL characters Dec 12 03:01:27 br0011 vmunix: You must reset the system time manually Dec 12 03:01:27 br0011 vmunix: Time of year (TOY) clock returned zero as the current time Dec 12 03:01:27 br0011 vmunix: Dec 12 03:01:27 br0011 vmunix: Dec 12 03:01:27 br0011 vmunix: WARNING: preposterous time in TOY clock -- CHECK AND RESET THE DATE!! Dec 12 03:01:27 br0011 vmunix: Dec 12 03:01:27 br0011 vmunix: i2c: Server Management Hardware Present Dec 12 03:01:27 br0011 vmunix: datalink: links=128, macs=6 Dec 12 03:01:27 br0011 vmunix: NOTE: dxb_configure: Configure values: dxb, ffffffffffffff9d, ffffffff90bfbf80, ffffffff90bf9a20 Dec 12 03:01:27 br0011 vmunix: WARNING: dxb_configure: configure_driver error = 22 Dec 12 03:01:28 br0011 vmunix: Node ID is 00-10-64-30-ae-38 (from device tu0) Dec 12 03:01:28 br0011 vmunix: WARNING: Time of year (TOY) clock battery is dead, time and NVR contents ignored Dec 12 03:01:28 br0011 vmunix: Dec 12 03:01:28 br0011 vmunix: You must reset the system time manually Cheers, uncle rubl

7 years, 2 months

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Re: [TUHS] Sleep()y musings

by jnc＠mercury.lcs.mit.edu

> From: Dave Horsfall > When did sleep(2) become sleep(3)? Was it V7, or some BSD? Before V7. The MIT system (~PWB1) says, on the man page for sleep (II), "As of this writing the system call is still available although the C routine implmeneting the function uses 'alarm' and 'pause' (II). It will be withdrawn when convenient." Probably left the system call there for compiled commands, etc which used it? Noel

7 years, 2 months

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Re: [TUHS] RIP Ray Tomlinson

by Doug McIlroy

> > But the concept of email goes way back. > Indeed, it does, but only on the same system. Very far back. CTSS had a mail utility. If communication within one system is not recognized as email, then the exchange that opened in Boston in 1877 was not a telephone system. Doug

7 years, 2 months

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RIP Ray Tomlinson

by Dave Horsfall

We lost Ray Tomlinson on this day in 2016; known as the inventor of email, he sent the first message between two hosts on the ARPAnet (prior to that the users had to be on the same host), and pioneered the use of the "@" sign. In the meantime, some tosser (his name is not important) is claiming that he invented email first; I recall that APL\360 had a "mailbox" facility, but it certainly didn't use "@". -- Dave Horsfall DTM (VK2KFU) "Those who don't understand security will suffer."

7 years, 2 months

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Re: [TUHS] [groff] The hyphenation algorithm produces wrong results

by Doug McIlroy

I hadn't realized that groff hyphenation had been taken from Tex, not troff. Is that becuase Tex did a better job, or because troff's was deemed proprietary?

7 years, 2 months

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new paper comparing Unix kernel designs

by Nelson H. F. Beebe

A new paper comparing Unix kernel designs was published earlier today: Stergios Papadimitriou and Lefteris Moussiades Mac OS versus FreeBSD: A Comparative Evaluation [IEEE] Computer 52(2), 44--53, February 2018 https://doi.org/10.1109/MC.2018.1451648 Despite the title, GNU/Linux also is included in the comparisons. The abstract is: >> ... >> FreeBSD (an open source Unix-like OS) and Apple's Mac OS use similar >> BSD functionality but take different approaches. FreeBSD implements a >> traditional compact monolithic Unix kernel, whereas Mac OS builds the >> BSD Unix functionality on top of the Mach microkernel. The authors >> provide an in-depth technical investigation of both approaches. >> ... Our fellow list member Larry McVoy, and his lmbench suite, are mentioned in the article, along with results of that suite. There are about 200 numbers in the two large tables of performance measurements, and while many are comparable across operating systems, there are some benchmarks that show up to a 40x difference between systems on the same hardware. ------------------------------------------------------------------------------- - Nelson H. F. Beebe Tel: +1 801 581 5254 - - University of Utah FAX: +1 801 581 4148 - - Department of Mathematics, 110 LCB Internet e-mail: beebe(a)math.utah.edu - - 155 S 1400 E RM 233 beebe(a)acm.org beebe(a)computer.org - - Salt Lake City, UT 84112-0090, USA URL: http://www.math.utah.edu/~beebe/ - -------------------------------------------------------------------------------

7 years, 2 months

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Some articles about early usenet

by arnold＠skeeve.com

https://www.cs.columbia.edu/~smb/blog//2018-02/2018-02-23.html By Steve Bellovin on "Usenet, Authentication, and Engineering (or: Early Design Decisions for Usenet)" http://www.newsweek.com/april-fools-day-april-fools-kremvax-kremlin-soviet-… On the Kremvax April Fools joke. Arnold

7 years, 2 months

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Re: [TUHS] EOF on pipes?

by Rudi Blom

pipes in SCO UNIX 3.2V4.2, It's long, long ago, so excuses for vagueness. I think the issue was not pipe() perse, but the difference in functionality between 'pipe filesystem' and streams pipes. By using pipe() you create a FIFO pipe with certain limitations (including 5120 write limit). When you open the streams device twice and ioctl() two file descriptors together you have more flexibility. Excuses for the possible confusion.

7 years, 2 months

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You can buy an Ultimate Machine...

by Dave Horsfall

Following the Claude Shannon discussion: http://www.jaycar.com.au/useless-box/p/GT3706 I tried to explain to the Young Thing (tm) behind the shop counter that it was invented several decades ago etc, but I suspect it was beyond her ken... -- Dave Horsfall DTM (VK2KFU) "Those who don't understand security will suffer."

7 years, 2 months

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Re: [TUHS] RIP Claude Shannon

by Doug McIlroy

> [Bob Fano} still has a reverential photograph of Shannpn > hanging in his office. Alas, no, Fano died in 2016 at age 98. More memories: Fano was among the grad students who came to ice-skating parties at our house in the mid-40s--the house near Shannon's later abode. I did not really get to know him until Multics days. His gravelly mafioso voice would scare you off--until you saw the irrepressible twinkle in his eye. A beloved and inspiring leader, worthy of Dave Horsfall's calendar. Doug

7 years, 2 months

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Re: [TUHS] EOF on pipes?

by Rudi Blom

>From a piece of code I have in some SCO UNIX 3.2V4.2 source. SCO doesn't have pipes, but you can simulate them. int fd[2] int rc; struct strfdinsert ins; queue_t *pointer = (queue_t *)NULL; rc = -1; /* * First open the stream clone device "/dev/spx" twice, * obtaining the two file descriptors. */ if ( (fd[0] = open(SPX_DEVICE, O_RDWR)) < 0) { gen_trace(gtr_flag, "-gen_pipe(): -open(fd[0]): %s\n", strerror(errno)); break; } if ( (fd[1] = open(SPX_DEVICE, O_RDWR)) < 0) { gen_trace(gtr_flag, ">gen_pipe(): -open(fd[1]): %s\n", strerror(errno)); close(fd[0]); break; } /* * Now link these two streams together with an * I_FDINSERT ioctl. */ ins.ctlbuf.buf = (char *) &pointer; /* no ctl info, just the ptr */ ins.ctlbuf.maxlen = sizeof(queue_t *); ins.ctlbuf.len = sizeof(queue_t *); ins.databuf.buf = (char *) 0; /* no data to send */ ins.databuf.len = -1; /* magic: must be -1, not 0, for stream pipe */ ins.databuf.maxlen = 0; ins.fildes = fd[1]; /* the fd to connect with fd[0] */ ins.flags = 0; /* nonpriority message */ ins.offset = 0; /* offset of pointer in control buffer */ if (ioctl(fd[0], I_FDINSERT, (char * ) &ins) < 0) { gen_trace(gtr_flag, ">gen_pipe(): -ioctl(I_FDINSERT): %s\n", strerror(errno)); close(fd[0]); close(fd[1]); break; }

7 years, 2 months

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Unix without pipes

by Ron Natalie

If I'm remembering correctly, miniunix didn't have pipes. The shell faked it by taking the output of the first program into a file and then using it as the input for the second. Didn't really multitask anyhow, so it was pretty much fine. -----Original Message----- From: TUHS [mailto:tuhs-bounces@minnie.tuhs.org] On Behalf Of Ian Zimmerman Sent: Monday, February 26, 2018 11:58 AM To: tuhs(a)minnie.tuhs.org Subject: Re: [TUHS] EOF on pipes? On 2018-02-26 23:03, Rudi Blom wrote: > From a piece of code I have in some SCO UNIX 3.2V4.2 source. SCO > doesn't have pipes, but you can simulate them. Is this a SCO speciality, or are there other UNIXes like that? Does it not even have pipe() in its libc?

7 years, 2 months

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EOF on pipes?

by Norman Wilson

Many years ago (when the dinosaurs were using V6), I had a crazy idea[*] that a write(fd, 0, NULL) would somehow signal EOF to the reader i.e. a subsequent read would wait for further data instead of ENOTOBACCO. Did any *nix ever implement that? I have no idea how it would be done. Have an ENOGORILLA. To answer the real question: stream pipes, which became the only sort of pipe in the Research stream (sic) sometime between the 8/e and 9/e manuals. The implementation was trivial, because from the beginning the metadata within a stream admitted delimiters: markers that meant `when this object reaches read(2) at the head end, return from read with whatever has already been delivered.' Empty messages (two consecutive delimiters) were explicitly allowed. If a stream was marked as using delimeters (and pipes always were), a delimeter was inserted after every write(2). So write(2) generated an empty message, and read(2) returned it. Norman Wilson Toronto ON

7 years, 2 months

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RIP Claude Shannon

by Dave Horsfall

We lost Claude Shannon on this day in 2001. He was a mathematician, electrical engineer, and cryptographer; he is regarded as the "father" of information theory, and he pioneered digital circuit design. Amongst other things he built a barbed-wire telegraph, the "Ultimate Machine" (it reached up and switched itself off), a Roman numeral computer ("THROBAC"), the Minivac 601 (a digital trainer), a Rubik's Cube solver, a mechanical mouse that learned how to solve mazes, and outlined a chess program (pre-Belle). He formulated the security mantra "The enemy knows the system", and did top-secret work in WW-2 on crypto and fire-control systems. -- Dave Horsfall DTM (VK2KFU) "Those who don't understand security will suffer."

7 years, 2 months

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Re: [TUHS] TUHS Digest, Vol 27, Issue 60

by Will Senn

Re: RIP Claude Shannon > Never heard of Claude Shannon. So a good opportunity to do some > searching reading to 'catch up'. Shannon did some amazing work. My field is Information science and without Shannon, it would be a dull field indeed. His masters thesis laid out an elegant use of digital logic for switching systems that we take for granted today, his mathematical theory of communication, while dense, is foundational - ever heard of a bit?, and he actually loved juggling so much he created a juggling machine - what’s not to love? :) All that said, he was also in the right place at the right time and was surrounded by genius. Will

7 years, 2 months

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Re: [TUHS] RIP Claude Shannon

by Doug McIlroy

> But a note on Dijkstra's algorithm: Moore and Dijsktra both published > in 1959. I was off by one on the year, but the sign of the error is debatable. Moore's paper was presented in a conference held in early April, 1957, proceedings from which were not issued until 1959. I learned about it from Moore when I first I met him, in 1958. Then, he described the algorithm in vivid, instantly understandable terms: imagine a flood spreading at uniform speed through the network and record the distance to nodes in order of wetting. > But it is documented Dijkstra's algorithm has been invented and used > by him in 1956. Taking into account the lead time for conference submissions, one can confidently say that Moore devised the algorithm before 1957. I do not know, though, when it first ran on a Bell Labs computer. That said, Moore's paper, which presented the algorithm essentially by example, was not nearly as clear as the capsule summary he gave me. It seems amateurish by comparison with Dijkstra's elegant treatment. Dijkstra's name has been attached to the method with good reason. Doug

7 years, 2 months

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Re: [TUHS] EOF on pipes?

by Doug McIlroy

>> pipe, ch(e)root.... Any more unix connections to smoking? I have a slide that's a quadralingual pun (French, English, Art, shell) in which Magritte's painting of a pipe with the words "Ceci n'est pas une pipe" has been altered to read "Ceci n'est pas une |". The altered phrase was borrowed from Jay Misra et al, who used it as an example of a message in a paper on communicating processes.

7 years, 2 months

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EOF on pipes?

by Dave Horsfall

Many years ago (when the dinosaurs were using V6), I had a crazy idea[*] that a write(fd, 0, NULL) would somehow signal EOF to the reader i.e. a subsequent read would wait for further data instead of ENOTOBACCO. Did any *nix ever implement that? I have no idea how it would be done. [*] I was full of crazy ideas then, such as extending stty() to an arbitrary device and was told by the anti-CSU mob that it was a stupid idea... -- Dave Horsfall DTM (VK2KFU) "Those who don't understand security will suffer."

7 years, 2 months

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Re: [TUHS] [TUHS} RIP Claude Shannon

by Doug McIlroy

So many memories. The "ultimate machine" (which was brought out and demonstrated from time to time while I was at the Labs) was built in collaboration with Ed Moore (he of Moore-model automata, who published "Dijkstra's algorithm" for shortest paths a year before Dijkstra) and (I believe) Dave Hagelbarger. Moore endowed the machine with a longevity property seldom remarked on: majority logic so that any electrical component can be removed without harming its observable behavior. Shannon moved to MIT from Bell Labs some weeks before I moved the other way, so I only met him much later when he visited the Unix room (an excuse, albeit weak, for this distant detour from TUHS). By that time Shannon was descending into Alzheimer's fog, but his wife who accompanied him was a memorably curious and perceptive visitor. I have wondered what role she may have played as a sounding board or more in Shannon's research. As a child, I used to ski on the 50-foot hill that was the lawn of the mansion that Shannon would buy when he moved to Massachusetts. We kids would ski down and climb back up. Not Shannon. He installed a chairlift. One house separated mine from the ski hill. It belonged to John Trump, another MIT prof who engineered the Van de Graaff generator into a commercial product for generating million-volt x-rays and, yes, was uncle of the Donald. John, as kind as he was bright, fortunately did not live to see the apotheosis of his wayward nephew. Doug > We lost Claude Shannon on this day in 2001. He was a mathematician, > electrical engineer, and cryptographer; he is regarded as the "father" of > information theory, and he pioneered digital circuit design. Amongst > other things he built a barbed-wire telegraph, the "Ultimate Machine" (it > reached up and switched itself off), a Roman numeral computer ("THROBAC"), > the Minivac 601 (a digital trainer), a Rubik's Cube solver, a mechanical > mouse that learned how to solve mazes, and outlined a chess program > (pre-Belle). He formulated the security mantra "The enemy knows the > system", and did top-secret work in WW-2 on crypto and fire-control > systems.

7 years, 2 months

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Re: [TUHS] RIP Claude Shannon

by Rudi Blom

Never heard of Claude Shannon. So a good opportunity to do some searching reading to 'catch up'. Interesting person and this quota tends to make him my type of guy "I just wondered how things were put together. – C.E. Shannon" http://themathpath.com/documents/ee376a_win0809_aboutClaudeShannon_willywu.… Now wondering if I should register for this THORIAC project or just read some more and do it. Not in the mood for learning Python I'd probably do some fumbling in C. https://www.engage-csedu.org/find-resources/shannons-throbac Keeps me busy and amuzed, uncle rubl

7 years, 2 months

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Pipes as temp. files

by Dave Horsfall

Just curious; am I the only who, back in the early days of V6, used pipes as temporary files? I mean that after calling pipe(), instead of then forking and playing "file-descriptor footsie" you just read and wrote within the same process. I seem to recall that it worked, as long as you avoided the 8-block limit (or whatever it was then); I have no idea why I tried it, other than to see if it worked i.e. avoid the creat() (without the "e") etc. -- Dave Horsfall DTM (VK2KFU) "Those who don't understand security will suffer."

7 years, 3 months

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Dave Cutler (was Re: Re: Happy birthday, Dick Hustvedt!)

by Paul Winalski

On 2/20/18, Donald ODona <mutiny.mutiny(a)india.com> wrote: > since '86 he was working on an operating system, named Mica, which failed. > > At 19 Feb 2018 18:13:59 +0000 (+00:00) from Paul Winalski > <paul.winalski(a)gmail.com>: >> Dave Cutler was in the VMS group only for VMS version 1. He rarely >> stayed on around for version 2 of anything. Hustvedt's and Lipman's >> contributions for VMS were more extensive and longer-lasting than >> Cutler's. Cutler had already left the VMS OS group by the time I joined DEC in February of 1980. After VMS he led the team developing PL/I and C compilers for VMS. These shared a common back end called the VAX Code Generator (VCG). The other VMS compilers at the time (Fortran, Pascal, Cobol) had their own separate optimizers and code generators. The VAX Ada compiler would also use VCG. When version 1 of VAX PL/i and VAX C shipped, Cutler worked on subsetting the VAX architecture so that a single chip implementation could be done, and led the team that produced the MicroVAX I. The MicroVAX architecture emulated expensive instructions such as packed decimal. All of the later, single-chip VAXes used this architecture. When the MicroVAX I shipped, Cutler devised a microkernel-based real-time operating system for the VAX called VAXeln. After VAXeln, Cutler led the team developing a RISC architecture follow-on to the VAX called PRISM, and an operating system for it called Mica. Mica had a VAXeln-like microkernel, and the plan was to layer personality modules on top of that to implement VMS and Unix-style ABIs and system calls. Alpha was chosen instead of PRISM as the VAX successor, and that is when Cutler left DEC for Microsoft. Windows NT has a lot of design concepts and details previously seen in PRISM and VMS. -Paul W.

7 years, 3 months

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VMS C / Whitesmiths

by Ron Natalie

At Rutgers Newark, we had VMS system that had Whitesmith's C on it. At one point, Whitesmiths decided to "fight piracy" by sending you a sticker you were supposed to stick on the front of your computer to show that you had a licensed copy. I suppose I might have been in trouble if the Whitesmiths police came to my machine room. I was a bit miffed when one of the other employees actually stuck the thing to the machine. Years later I was loosely affiliated with Unipress. I did some consulting for them when I was between jobs. I went out to dinner with their principal, a man named Mark Krieger. After a bit of conversation it occurred to me. "Didn't you get booed off the stage at the University of Delaware UNIX users group meeting." He admitted he had, he was half of Whitesmiths with Paul Plauger. It then came back to me about Idris and the software stamps. I mentioned the stamps and he said he was gone by then but that was his sign that Plauger had gone over the edge. I carefully peeled our sticker off the Vax and gave it to him the next time I saw him.

7 years, 3 months

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Happy birthday, Dick Hustvedt!

by Dave Horsfall

Let's see how much thread-drift I can generate this time... Dick Hustvedt was born on this day in 1946; an architect of RSX-11 and VMS, he also had a weird sense of humour which he demonstrated by enshrining the "microfortnight" into VMS. Sadly, we lost him in a car accident in 2008. -- Dave Horsfall DTM (VK2KFU) "Those who don't understand security will suffer."

7 years, 3 months

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Do Interface specifications such POSIX or the LSB Still Matter

by Clem Cole

I've send a couple of you private messages with some more details of why I ask this, but I'll bring the large question to debate here: Have POSIX and LSB lost their usefulness/relevance? If so, we know ISV’s like Ansys are not going to go ‘FOSS’ and make their sources available (ignore religious beliefs, it just is not their business model); how to we get that level of precision to allow the part of the market that will be 'binary only' continue to create applications? Seriously, please try to stay away from religion on this question. Clearly, there are a large number of ISVs have traditionally used interface specifications. To me it started with things like the old Cobol and Fortran standards for the languages. That was not good enough since the systems diverge, and /usr/group then IEEE/ANSI/ISO did Posix. Clearly, Posix enabled Unix implementations such a Linux to shine, although Linux does not doggedly follow it. Apple was once Posix conformant, but I'd not think they worry to much about it. Linux created LSB, but I see fewer and fewer references to it. I worry that without a real binary definition, it's darned hard (at least in the higher end of the business that I live day-to-day) to get ISV's to care. What do you folks think? Clem

7 years, 3 months

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Re: [TUHS] Happy birthday, Niklaus Wirth!

by Norman Wilson

As an aside about Wolfram and SMP (and one that actually has something to do with UNIX): I ran the VAX on which Wolfram et al (and it was very much et al) developed SMP. It started out running UNIX/TS 1.0. I know how that system was snuck out of Bell Labs, but if I told you I'd have to terminate you with extreme prejudice. (I wasn't involved anyway.) SMP really needed dynamic paging; the TS 1.0 kernel had only swapping. We had quite a few discussions about what to do. Moving wholesale to 3BSD or early 4BSD (this was in 1981) would have been a big upheaval for our entire user community. Those systems were also notorious at the time for their delicate stability: some people reported that they ran well, others that they crashed frequently. Our existing system was pretty solid, and I had already put some work into making it more so (better handling of low-level machine errors, for example). Somehow we ended up deciding that the least-painful path was to lift the VM code out of 4BSD and shoehorn it into our existing kernel, creating what we called Bastardized Paging UNIX. I did most of the work; I was younger and more energetic back then. Also considerably grumpier. In the heart of the page-in (I think) code, the Berkeley guys had written a single C function that stretched to about ten printed pages. (For those too young to remember printers, that means about 600 lines.) I was then and still am adamant that that's the wrong way to write anything, but I didn't want to take the time to rewrite it all, so (being young and grumpy) I relieved my feelings by adding a grumpy comment at the top of the source file. I also wrote a paper about the work, which was published in (of all places) AUUGN. I haven't read it in years but it was probably a bit snotty. It nevertheless ended up causing a local UNIX-systems-software company to head-hunt me (but at the time I had no interest in leaving Caltech), so it must not have been too rude. What days those were, when a single person could understand enough of the OS to do stuff like that in only a month or two, and get it pretty much right too. I did end up finding some interesting race-condition bugs, probably introduced by me, but fascinating to track down; e.g. something that went wrong only if a page fault happened at exactly the right time with respect to something else. Norman Wilson Toronto ON

7 years, 3 months

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Re: [TUHS] PDP-7 Unix Paper

by Norman Wilson

Donald ODana: already 20 years ago I met a guy (masters degree, university) who never freed dynamically allocated memory. He told me he is 'instantiating a object', but had no idea what an heap is, and what dynamically allocated memory means. ==== This is the sort of programmer for whom garbage collection was named: his programs are a collection of garbage. Norman Wilson Toronto ON (In 1127-snark mode this evening)

7 years, 3 months

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Re: [TUHS] Of birthdays etc

by Rudi Blom

>Date: Sat, 17 Feb 2018 17:47:22 +1100 (EST) >From: Dave Horsfall <dave(a)horsfall.org> >To: The Eunuchs Hysterical Society <tuhs(a)tuhs.org> >Subject: [TUHS] Of birthdays etc >Message-ID: <alpine.BSF.2.21.1802171649520.798(a)aneurin.horsfall.org> >Content-Type: text/plain; format=flowed; charset=US-ASCII > >... >Harris' Lament? Look it up with your favourite search engine (I don't use Google). > probably early 1995 I dabbled a bit in AltaVista Search. So even now still using Yahoo somehow :-) Keep it coming Dave, it's appreciated, at least by me. >From a former DECcie, uncle rubl

7 years, 3 months

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Of birthdays etc

by Dave Horsfall

Blimey... How was I to know that a throw-away remark would almost develop into a shitfight? It would help if people changed the Subject line too, as I'm sure that Ken must've been a little peeved... It would also help if users didn't bloody top-post either, but I suspect that I've lost that fight. Anyway, this whole business started when I thought it might be a good idea to post reminders of historical events here, as I do with some of the other lists that I infest^W infect^W inhabit. I figured that the old farts here might like to be reminded of (IMHO) significant events, and similarly the youngsters might want to be reminded that there was indeed life before Linux (which, by the way, I happen to loathe, but that's a different story). I'm glad that some people appreciate it; and don't worry, Steffen, you'll soon catch up, as they should all be in the archives :-) A long-term goal (if I live that long) is to set up one of those "this day in history" sites, but it looks like Harris' Lament[*] has already applied :-( I've had a number of corrections (thanks!), some weird comments on pronunciation (an Englishman can probably pick my ancestry from me saying "castle" as "c-AH-stle" and "dance" as "d-A-nce" etc), but oddly enough no criticism (well, unless I'm talking about mounting a magtape as a filesystem; no, I will not forget the implication that I was a liar), and Warren has yet to spank me... For the morbidly curious I keep these events in Calendar on my MacBook (which actually spends most of its time in Terminal, and I don't even know how to use the Finder!), and am always noting things which interest me and therefore possibly others. Anyway, thanks all; it is an honour and a privilege to share a mailing list with some of the people who wrote the software that I have both used in the past and still use to this day. [*] Harris' Lament? Look it up with your favourite search engine (I don't use Google). -- Dave Horsfall DTM (VK2KFU) "Those who don't understand security will suffer."

7 years, 3 months

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Re: [TUHS] TUHS Digest, Vol 27, Issue 37

by Paul McJones

> On Feb 14, 2018, Dave Horsfall <dave(a)horsfall.org> wrote: > > Computer pioneer Niklaus Wirth was born on this day in 1934; he basically > designed ALGOL, one of the most influential languages ever, with just > about every programming language in use today tracing its roots to it. Wirth designed many languages, including Euler, Algol W, Pascal, Modula, and Oberon, but he did not design Algol; more specifically, he did not design Algol 60. Instead, a committee (J. W. Backus, F. L. Bauer, J. Green, C. Katz, J. McCarthy, P. Naur, A. J. Perlis, H. Rutishauser, K. Samelson, B. Vauquois, J .H. Wegstein, A. van Wijngaarden, and M. Woodger) designed it, and Peter Naur edited the remarkable Algol 60 specification. A few others, including Edsgar Dijkstra, who completed the first implementation, participated in meetings leading up to the final design.

7 years, 3 months

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Re: [TUHS] Happy Birthday, Nicklaus Wirth

by Paul Ruizendaal

From: Doug McIlroy <doug(a)cs.dartmouth.edu> > Like PL/I, it also > borrowed the indispensable notion of structs from business languages > (Flowmatic, Comtran, Cobol). That is an interesting insight. I always thought that structs were inspired by the assembler DORG construct, and hence the shared namespace for members. The above insight goes some way to explain why PDP11 “as” did not have a DORG construct, but early C did have ‘struct'. Paul

7 years, 3 months

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And it's time to close the C vs. Lisp thread

by Warren Toomey

as it's strayed too far from the charter of the TUHS mailing list. There must be a more suitable forum to discuss language issues! Thanks, Warren

7 years, 3 months

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lisp challenge

by Larry McVoy

So people have called me on the claim that lisp is not fast. Here's a rebuttal. Please write a clone of GNU grep in lisp to demonstrate that the claim that lisp is slower that C is false. Best of luck and I'll be super impressed if you can get even remotely close without dropping into C or assembler. If you do get close, I will with draw my claim, stand corrected, point future "lisp is slow" people at the lisp-grep, and buy you dinner and/or drinks. --lm

7 years, 3 months

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Re: [TUHS] lisp challenge

by jnc＠mercury.lcs.mit.edu

> From: Larry McVoy <lm(a)mcvoy.com> > the proof here is to show up with a pure lisp grep that is fast as the C > version. ... I've never seen a lisp program that out performed a well > written C program. Your exact phrase (which my response was in reply to) was "lisp and performance is not a thing". You didn't say 'LISP is not just as fast as C' - a different thing entirely. I disagreed with your original statement, which seems to mean 'LISP doesn't perform well'. Quite a few people spent quite a lot of time making LISP compiler output fast, to the point that it was possible to say "this compiler is also intended to compete with the S-1 Pascal and FORTRAN compilers for quality of compiled numeric code" [Brooks,Gabriel and Steele, 1982] and "with the development of the S-1 Lisp compiler, it once again became feasible to implement Lisp in Lisp and to expect similar performance to the best hand-tuned, assembly-language-based Lisp systems" [Steele and Gabriel, 1993]. Noel

7 years, 3 months

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[Re: Happy Birthday, Nicklaus Wirth

by Doug McIlroy

> Computer pioneer Niklaus Wirth was born on this day in 1934; he basically > designed ALGOL, one of the most influential languages ever, with just > about every programming language in use today tracing its roots to it. Rather than "tracing its roots to it", I'd say "has some roots in it". Algol per se hardly made a ripple in the US market, partly due to politics and habit, but also because it didn't espouse separate compilation. However, as asserted above, it had a profound impact on language designers and counts many languages as descendants. To bring the subject back to Unix, C followed Fortran's modularity and Algol's block structure. (But it reached back across the definitive Algol 60 to pick up the "for" statement from Algol 58.) Like PL/I, it also borrowed the indispensable notion of structs from business languages (Flowmatic, Comtran, Cobol). It adopted pointers from Lisp, as polished by BCPL (pointer arithmetic) and PL/I (the -> operator). For better or worse, it went its own way by omitting multidimensional arrays. So C has many roots. It just isn't fashionable in computer-language circles to highlight Cobol in your family tree. Doug

7 years, 3 months

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Re: [TUHS] Happy birthday, Niklaus Wirth!

by jnc＠mercury.lcs.mit.edu

> From: Larry McVoy <lm(a)mcvoy.com> > I don't know all the details but lisp and performance is not a thing. This isn't really about Unix, but I hate to see inaccuracies go into archives... You might want to read: http://multicians.org/lcp.html Of course, when it comes to the speed/efficientcy of the compiled code, much depends on the program/programmer. If one uses CONS wildly, there will have to be garbage collection, which is of course not fast. But properly coded to stay away from expensive constructs, my understanding is that 'lcp' and NCOMPLR produced pretty amazing object code. Noel

7 years, 3 months

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Re: [TUHS] Happy birthday, Niklaus Wirth!

by Paul McJones

Actually, Algol 60 did allow functions and procedures as arguments (with correct static scoping), but not as results, so they weren’t “first class” in the Scheme sense. The Algol 60 report (along with its predecessor and successor) is available, among other places, here: http://www.softwarepreservation.org/projects/ALGOL/standards/ On Feb 16, 2018, Bakul Shah <bakul(a)bitblocks.com> wrote: > They did lexical scoping "right", no doubt. But back when > Landin first found that lambda calculus was useful for > modeling programming languages these concepts were not clearly > understood. I do not recall reading anything about whether > Algol designers not allowing full lexical scopin was due to an > oversight or realizing that efficient implementation of > functional argument was not possible. May be Algol's call by > name was deemed sufficient? At any rate Algol's not having > full lexical scoping does not mean one can simply reject the > idea of being influenced by it. Often at the start there is > lots of fumbling before people get it right. May be someone > should ask Steele?

7 years, 3 months

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Re: [TUHS] Clueless programmers

by Rudi Blom

Clueless or careless? A customer program worked for many years till one of the transaction messages had a few bytes added. Looking into it I discovered that the program had only worked because the receive buffer was followed by another buffer which was used in a later sequence. Only when also that buffer overflowed some critical integers got overwritten and used as index in tables that gave a lot of fun. Well, as all here know, C is fun :-)

7 years, 3 months

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Re: [TUHS] Happy birthday, Niklaus Wirth!

by jnc＠mercury.lcs.mit.edu

> From: Larry McVoy <lm(a)mcvoy.com> I am completely non-LISP person (I think my brain was wired in C before C existed :-), but... > Nobody has written a serious operating system Well, the LISP Machine OS was written entirely in LISP. Dunno if you call that a 'serious OS', but it was a significantly more capable OS than, say, DOS. (OK, there was a lot of microcde that did a lot of the low-level stuff, but...) > or a serious $BIG_PROJECT in Lisp. Have you ever seen a set of Symbolics manuals? Sylph-like, it wesn't! > Not one that has been commercially successful, so far as I know. It's true that Symbolics _eventually_ crashed, but I think the biggest factor there was that commodity microprocessors (e.g. Pentium) got faster so much faster than Symbolics' custom LISP hardware, so that the whole rationale for Symbolics (custom hardware to run LISP fast) went away. They still exist as a software company selling their coding environment, FWTW. > C performs far better even though it is, in the eyes of lisp people, far > more awkward to do things. I think it depend on what you're doing. For some kinds of things, LISP is probably better. I mean, for most of the kind of things I do, I think C is the bees' knees (well, except I had to add conditions and condition handlers when I went to write a compiler in it), but for some of the AI projects I know a little about, LISP seems (from a distance, admittedly) to be a better match. Noel

7 years, 3 months

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Re: [TUHS] Happy birthday, Niklaus Wirth!

by Paul McJones

On Feb 15, 2018, Ian Zimmerman <itz(a)very.loosely.org> wrote: >> >> So, how's this relevant to Unix? Well, I'd like to know more about the >> historical interplay between the Unix and Lisp communities. What about >> the Lisp done at Berkeley on the VAX (Franz Lisp). > > I know one of the Franz founders, I'll ask him when I have a chance. There is some information about Franz Lisp and its origins here: http://www.softwarepreservation.org/projects/LISP/maclisp_family/#Franz_Lis… (And lots more information about many other varieties of Lisp at the same web site.)

7 years, 3 months

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Re: [TUHS] Windows roots and Unix influence (was Re: Happy birthday, Ken Thompson!)

by Dan Cross

On Sat, Feb 3, 2018 at 5:59 PM, Dave Horsfall <dave(a)horsfall.org> wrote: > On Sat, 3 Feb 2018, Arthur Krewat wrote: > >> I would imagine that Windows wouldn't be what it is today without UNIX. >> Matter of fact, Windows NT (which is what Windows has been based on since >> Windows ME went away) is really DEC's VMS underneath the covers at least to >> a small extent. >> > > I thought that NT has a POSIX-y kernel, which is why it was so reliable? > Or was VMS a POSIX-like system? I only used it for a couple of years in > the early 80s (up to 4.0, I think), and never dug inside it; to me, it was > just RSX-11/RSTS-11 on steroids. The design of the original NT kernel was overseen by Dave Cutler, of VMS and RSX-11M fame, and had a very strong and apparent VMS influence. Some VAX wizards I know told me that they saw a lot of VMS in NT's design, but that it probably wasn't as good (different design goals, etc: apparently Gates wanted DOS++ and a quick time to market; Cutler wanted to do a *real* OS and they compromised to wind up with VMS--). It's true that there was (is? I don't know anymore...) a POSIX subsystem, but that seemed more oriented at being a marketing check in the box for sales to the US government and DoD (which had "standardized" on POSIX and made it a requirement when investing in new systems). Now days, I understand that one can run Linux binaries natively; the Linux-compatibility subsystem will even `apt-get install` dependencies for you. Satya Nadella's company isn't your father's Microsoft anymore. VSCode (their new snazzy editor that apparently all the kids love) is Open Source. Note that there is some irony in the NT/POSIX thing: the US Government standardized on Windows about two decades ago and now can't seem to figure out how to get off of it. A short story I can't resist telling: a couple of years ago, some folks tried to recruit me back into the Marine Corps in some kind of technical capacity. I asked if I'd be doing, you know, technical stuff and was told that, since I was an officer no, I wouldn't. Not really interested. I ended up going to a bar with a recon operator (Marine special operations) to get the straight scoop and talking to a light colonel (that's a Lieutenant Colonel) on the phone for an hour for the hard sell. Over a beer, the recon bubba basically said, "It was weird. I went back to the infantry." The colonel kept asking me why I didn't run Windows: "but it's the most popular operating system in the world!" Actually, I suspect Linux and BSD in the guise of iOS/macOS is running on a lot more devices than Windows at this point. I didn't bother pointing that out to him. Would VMS become what it was without UNIX's influence? Would UNIX become >> what it later was without VMS? >> >> Would UNIX exist, or even be close to what it became without DEC? >> > > I've oft wondered that, but we have to use a new thread to avoid > embarrassing Ken :-) > The speculation of, "what would have happened?" is interesting, though of course unanswerable. I suspect that had it not been for Unix, we'd all be running software that was closer to what you'd find on a mainframe or RT-11. - Dan C.

7 years, 3 months

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Clueless programmers

by Ron Natalie

> already 20 years ago I met a guy (masters degree, university) who never freed dynamically allocated memory. He told me he is 'instantiating a object', but had no idea what an heap is, and what dynamically allocated memory means. Years ago, I had an new programmer who I just couldn't teach. He never understood the difference between an array and pointer, and apparently couldn't be bothered to learn. After string him along for three months, I was on my way into his office to fire him when I found out he had quit, but not before he checked a bunch of drek into our source code control system. I thought I backed all his commits out at the time. Years later I was running "purify" on our product looking for memory leaks. I found this small utility function that predated the source code control system leaking. This, I thought was odd, as it had been there FOREVER and was well tested. I brought up the source code system and checked it anyhow and found the afore mentioned programmer had checked in one change: he deleted the "free" call in it. I KNOW what happened. He did something else to corrupt the malloc heap in his code and often this causes a core dump in a subsequent malloc/free call. Apparently this was the place it struck him, so he just deleted the free call there.

7 years, 3 months

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Oddness in V6 'mv'

by jnc＠mercury.lcs.mit.edu

So, in: http://minnie.tuhs.org/cgi-bin/utree.pl?file=V6/usr/source/s2/mv.c what's the point of this piece of code: p = place; p1 = p; while(*p++ = *argp3++); p2 = p; while(*p++ = *argp4++); execl("/bin/cp","cp", p1, p2, 0); I mean, I get that it's copying the two strings pointed to by 'argp3' and 'argp4' into a temporary buffer at 'place', and leaving 'p1' and 'p2' as pointers to the copies of said strings, but... why is it doing that? I at first thought that maybe the execl() call was smashing the stack (and thus the copies pointed to by 'argp3' and 'argp4'), or something, but I don't think it does that. So why couldn't the code have just been: execl("/bin/cp","cp", argp3, argp4, 0); Is this code maybe just a left-over from some previous variant? Noel

7 years, 3 months

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pdp-11 assembly as a hll?

by Warner Losh

I don't suppose anybody has written a pdp-11 assembler to C translator... My google fu is insufficient for the day. Warner

7 years, 3 months

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Re: [TUHS] pdp-11 assembly as a hll?

by jnc＠mercury.lcs.mit.edu

> From: Dave Horsfall <dave(a)horsfall.org> > I'd like to see it handle "JSR PC,@(SP)+"... Heh! But that does point out that the general concept is kind of confused - at least, if you hope to get a fully working program out the far end. The only way to do that is build (effectively) a simulator, one that _exactly_ re-creates the effects on the memory and registers of the original program. Only instead of reading binary machine code, this one's going to read in the machine language source, and produce a custom simulator, one that can run only one program - the one fed into it. Think of it as a 'simulator compiler'! :-) Noel

7 years, 3 months

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PDP-7 Unix Paper

by Warren Toomey

All, my journal paper on PDP-7 Unix has just been licensed under CC-BY-SA, so here's a link to the PDF version: http://minnie.tuhs.org/Y5/wkt_hapop_paper.pdf Cheers, Warren

7 years, 3 months

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Re: [TUHS] pdp-11 assembly as a hll?

by Paul Ruizendaal

>> I was wondering what it would take to convert the v6/v7 basic program >> into something that can be run today. > > Hmmm... If it were C-generated then it would be (somewhat) easy, but it's > hand-written and hand-optimised... You'd have to do some functional > analysis on it e.g. what does this routine do, etc. > >> Its 2128 lines. It doesn't have that fun instruction in it :) > > I know! Say ~2,000 lines, say ~100 people on this list, distributed > computing to the rescue! That's only 20 lines each, so it ought to be a > piece of cake :-) I'm up for that! However, only if the resulting C program can be compiled/run on a V6/PDP11 again. Let's assume that reverse engineering a subroutine of 20 lines takes an hour. That then makes for 100 hours. If 10 people participate and contribute one hour/routine per week, it will be done by May. However, the initial analysis of the code architecture is a (time) hurdle. Paul PS: the Fortran66 of V6 is also assembler only...

7 years, 3 months

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Why BSD didn't catch on more, and Linux did

by Dan Stromberg

IMO: 1) It kinda did catch on, in the form of macOS, but there was a time when it was nearly dead as the major vendors moved to System V. For some reason, Sun was the last major vendor to make the move, but they caught most of the flack. 2) I think the main reason BSD nearly died, was the AT&T lawsuit. At the time, Linux appeared to be a safer bet legally. 3) Linux got a reputation as an OS you had to be an expert to install, so lots of people started it to install it to "prove themselves". This was sort of true back when Linux came as 2 floppy images, but didn't remain true for very long. 4) I believe the SCO lawsuit "against Linux" was too little, too late to kill Linux's first mover advantage in the opensource *ix department. 5) I think FreeBSD's ports and similar huge-source-tree approaches didn't work out as well Linux developers contributing their changes upstream.

7 years, 3 months

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qd32 trouble

by Jacob Ritorto

Hi all, Would anyone here be able to help me troubleshoot my qd32 controller? I have a pdp11/73 that's mostly working, boots 2.11 from rl02 okay, but I need my big disk to work so I can load the rest of the distro. I've been following the manual for the qd32 to enter the geometry of my real working m2333 (jumpered correctly according to the manuals), but when I load the special command into the qd32's SP register that's supposed to load the geometry table from the pdp11 memory to the novram, I get a bad status value from the qd32's SP register and it remains unresponsive when I try to store the geometry. If I go ahead and try the built-in qd32 format command, it responds similarly. When I pull in mkfs from tape (vtserver) and try anyway, despite the failures, to run mkfs on the m2333, I get an !online error from the standalone unix mkfs. The disk does respond (the select light flashes and I can hear heads actuating), but without geometry and format, I'm obviously dead in the water. Any suggestions on how to proceed? thx jake

7 years, 3 months

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Re: [TUHS] Device special files

by Doug McIlroy

> Why is it that umount(2) took the device special file name rather than the mount point directory name, anyway? Symmetry. You unmount what you mount. A competing model is that of links. Link makes an old file available under a new name. But you unlink by the new name. Necessarily so, because there may be many new names for one old file. This is reminiscent of Don Norman's screed about the unnaturalness of Unix. He didn't like strcpy because the arguments come in the opposite order to those of cp. But stcpy is part of C, and in C the destination of assignment comes before the source. But Norman didn't rail at C. You pays your money and takes your choice. Doug

7 years, 3 months

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Device special files

by ron minnich

these were in by the time I can along but I was wondering when they got it. They've also always felt a bit like a thing that did not fit to me. I'm pretty sure I was not alone, given that the Unix authors worked out a way to get rid of them in later efforts. I know what came after, in Plan 9; what came before, in Unix, that led to special files?

7 years, 3 months

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RIP John von Neumann

by Dave Horsfall

We lost computer pioneer John von Neumann on this day in 1957; the "von Neumann" architecture (stored program etc) is the basis of all modern computers, and he almost certainly borrowed it from Charles Babbage. -- Dave Horsfall DTM (VK2KFU) "Those who don't understand security will suffer."

7 years, 3 months

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Re: [TUHS] Device special files

by jnc＠mercury.lcs.mit.edu

> From: Greg Lehey >> V3 and earlier still *called* them special files, but it seems they >> were essentially just magic inode numbers (there was no physical file >> on disk, just any directory entry with the given inode would be the >> special file). > Isn't that still the case? >From reading the manual page (URL sent earlier), in V3 and before it really was just an inode _number_ (less than 50, IIRC). The first inode, in the first disk block after the super-block, was inode #51. This is of course different from later Versions, where there is an _inode_ for devices, but still no actual _file_. Noel

7 years, 3 months

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Happy birthday, Ken Thompson!

by Dave Horsfall

Co-inventor of Unix, he was born on this day in 1943. Just think: without those two, we'd all be running M$ Windoze and thinking that it's wonderful (I know, it's an exaggeration, but think about it). -- Dave Horsfall DTM (VK2KFU) "Those who don't understand security will suffer."

7 years, 3 months

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