TUHS

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6498 discussions

by Dave Horsfall

Someone on one of these lists seems to be at ok-labs.com; well... aneurin% host ok-labs.com ;; connection timed out; no servers could be reached aneurin% Houston, we have a problem... Could whoever is responsible please sprinkle some fairy dust somewhere? Thanks. -- Dave

3 years, 2 months

Memory on Lion's v6

by Will Senn

Does anybody know how much memory was configured on the PDP-11 that Lion's used for the commentary system. Here's what the book says about the system: ; from lions, page 1 ; The code selection presumes a "model" system consisting of: ; PDP11/40 processor; ; RK05 disk drives; ; LP11 line printer; ; PC11 paper tape reader/punch; ; KL11 terminal interface. I usually add the mag tape, too ; TM10 magnetic tape - not in lions, but super handy It seems like he must have had an MMU and 128k memory, but I don't know. I'm hoping y'all remember, know, or can otherwise divine the correct value. I've run with no MMU - crash on boot. I've also run with less memory, but then cc won't build mkconf, when I have the TM10 enabled kernel loaded. As a reminder, his book was published in 1977. Thanks, Will

3 years, 2 months

Re: [TUHS] Memory on Lion's v6

by jnc＠mercury.lcs.mit.edu

> From: Will Senn > Does anybody know how much memory was configured on the PDP-11 that > Lion's used for the commentary system. Here's what the book says about > the system: > .. > ; PDP11/40 processor; > ... > It seems like he must have had an MMU V6 absolutely requires an MMU; the need for it is all throughout basic attributes of the system - e.g. user processes start their address space at 0. (BTW, there are V6 descendants, MINI-UNIX: http://gunkies.org/wiki/MINI-UNIX and LSX, which don't use/need an MMU, and run on -11 models without memory managament, such as -11/05's, but I don't think they were in wide use outside Bell.) > and 128k memory The -11/40, as originally released, only supported the MM11-L, which came in multiples of 16KB (for a 3-board set). Use of the later MM11-U (32KB units) required a new main power harness, which only came in on higher-serial-numbered -11/40's. The -11/40 (as it was at first) that I had at LCS had, to start with, I'm pretty sure, 3 MM11-L units (i.e. one MM11-L backplane full) - i.e. 48KB. I know this sounds incredible, and I'm having a hard time believing it myself, wondering if my memory is failing with age; but it definitely had extraordinarily little. I just looked on my V6 (running in a simulator), and it appears that by trimming all parameters (e.g. number of disk buffers) to the absolute bone, the kernel could be trimmed to about 36KB. (I haven't actually tried it, since I don't feel like recompiling all the kernel modules, but one can estimate it - take the current system size [44KB], delete 10 buffers @ .5KB gives 39KB, etc, etc.) That would allow a maximum user process of 12KB on a 48KB machine - and MINI-UNIX, which runs basically stock V6 user code, can manage with user processes that small. I see Andrew's email which reports that the Lions machine had more main memory, 128KB (maybe 4 MM11-U's - two MM11-U backplanes full); that woould have made their life a lot easier. Noel

3 years, 2 months

Re: [TUHS] run commands at login in v6 and stty

by Douglas McIlroy

> The X11 tree was a heavily ifdef-ed. And it needed to be, I don't have > an answer as to how you would reuse all that code on different hardware > in a better way. Plan 9 did it with #include. The name of the included file was the same for every architecture. Only the search path for include files changed. Done with care, this eliminates the typical upfront #ifdefs.that define constants and set flags. Other preprocessor conditionals can usually be replaced by a regular if, letting the compiler optimize away the unwanted alternative. This makes conditionals obey the scope rules of C. Doug

3 years, 2 months

Re: [TUHS] run commands at login in v6 and stty

by Brian Walden

6th Edition used the Thompson shell as /bin/sh. I don't think it had those capabilities. Sometimes you could find an early version of the Bourne shell in /bin/nsh (new shell) in v6. The 7th Edition made the Bourne shell /bin/sh. And there sometimes you could find the Thompson shell in /bin/osh (old shell). Will Senn wrote: > Login commands question: > > I'm sure it's simple, but I can't figure it out. How do I get something > to run at login in v6? Right now, I use ed to create a file 'setprof' > that contains: > > stty erase[space][backspace][return] > stty nl0 cr0 > > Then after logging in: > > sh setprof > > It works, but, it is pretty clunky. > > stty question: > > So, I looked at stty.c and it looks like the following should work, if > the terminal is sending ^H for backspace: > > #define BS0 0 > #define BS1 0100000 > > modes[] > ... > "bs0", > BS0, BS1, > > "bs1", > BS1, BS1, > > > but: > > stty bs0 > or > stty bs1 > > don't result in proper backspace handling.. > > but: > > stty[space][^h][return] > > > works... > > Thoughts?

3 years, 2 months

run commands at login in v6 and stty

by Will Senn

Login commands question: I'm sure it's simple, but I can't figure it out. How do I get something to run at login in v6? Right now, I use ed to create a file 'setprof' that contains: stty erase[space][backspace][return] stty nl0 cr0 Then after logging in: sh setprof It works, but, it is pretty clunky. stty question: So, I looked at stty.c and it looks like the following should work, if the terminal is sending ^H for backspace: #define BS0 0 #define BS1 0100000 modes[] ... "bs0", BS0, BS1, "bs1", BS1, BS1, but: stty bs0 or stty bs1 don't result in proper backspace handling.. but: stty[space][^h][return] works... Thoughts?

3 years, 2 months

Re: [TUHS] run commands at login in v6 and stty

by jnc＠mercury.lcs.mit.edu

> From: Clem Cole > what I don't remember was it in v5 Your memory is going! :-) We discussed this recently (well, recently in _our_ timescale :-); it's built into in 'cc' in V5: https://minnie.tuhs.org/cgi-bin/utree.pl?file=V5/usr/source/s1/cc.c see "expand(file)". Noel

3 years, 2 months

Re: [TUHS] CSR in V6

by jnc＠mercury.lcs.mit.edu

> From: Will Senn > My question is - how did y'all run things - with CSR zero and no kernel > messages ... or with CSR non-zero and kernel messages. On the -11/45 V6+ at MIT, we didn't have a printing terminal on the console, just a VT52. We had a tool at MIT called 'dmesg': http://ana-3.lcs.mit.edu/~jnc/tech/unix/man8/dmesg.8 which made up for that a bit. We normally ran with the CSR set to 173030 - the 'boot in single-user' setting. That's because at one point the machine was in the 9th floor machine room, but the console VT52 was on the 5th floor (where our offices were - the famous print of the GE-645 Multics was on the hallway wall outside mine :-), and I'd added a 'reboot()' system call (nothing fancy, it just jumped to the bootstrap ROM), so we could reboot the machine without going up in the elevator (not if it had crashed, of course). Later on, after we'd done with kernel hacking (adding a network interface, and IP), and the machine stayed up for long periods, we moved the console up next to the machine (since if it crashed, you had to use the front panel to restart it, so you had to be up there anyway); we stayed with the default CSR setting, though. (If it panic'd, you could see the reason why when you went to reboot it.) > Oh, BTW, I know I've seen this noted elsewhere, but I can't remember > where. Maybe at: https://gunkies.org/wiki/UNIX_Sixth_Edition#Distros which discusses it? Noel

3 years, 2 months

CSR in V6

by Will Senn

I noticed in v6 source that putch in prf.c - the system kernel printf's character routine, only prints to the console if the Console Switch Register is non-zero. My question is - how did y'all run things - with CSR zero and no kernel messages (seems dangerous to me, being naive and all) or with CSR non-zero and kernel messages. On my FreeBSD instance, I value the messages that show up on console as they've alerted me to big problems in the past, but on my Mac, not as much (sure you can run Console and see them, but they aren't immediate). Oh, BTW, I know I've seen this noted elsewhere, but I can't remember where. Dennis's v6 doesn't have the Western Electric message: mem = 435 RESTRICTED RIGHTS Use, duplication or disclosure is subject to restrictions stated in Contract with Western Electric Company, Inc. It was a bit of a head scratcher as I was trying to read from the Dennis version of the distro on my mac while running Wellsch's tape on simh. I spent quite a while spinning my wheels looking for "Western" in the files to no avail. I thought something was screwy with the files or my mac.

3 years, 2 months

Lions v6 source code pdf

by Will Senn

All, I got sick of poring over my Peer-to-Peer communications version of Lion's commentary - trying to read it while digging around in v6 was getting annoying. Of course, if you don't already own, rush out and by a copy. It's great stuff. Anyhow, the problem is that it's perfect bound, landscape and it's not searchable. Hunting around the internet, I found pdfs that were searchable, but they were based on v7 being back-engineered to v6 code. So, I located a decent source of electronically readable Lion's source at https://warsus.github.io/lions-/ and off I went. I took the code and did a bit (quite a bit) of tweakage on it to get it formatted in pdf, and created a version in letter format that I find pretty useful. It can be read from a printout while messing around in v6. I've done some proofing, but I don't claim it's perfect. If you find any issues with it, let me know and I'll try to fix them (thanks, Clem for early suggestions). Here's what's in the letter sized pdf: Tweaked Cover Page Improved Table of Contents Lion's version of V6 Source Code Appendices Source File Sheets Alphabetical List Source File Locations in Running V6 System What isn't in the pdf: Original Forewords, Prefaces, or Letters (not needed for coding) Symbol Lists, Cross references, or Indexes (beyond my skills at the moment) All in all, I have found it quite readable and useful for my own work. I don't claim any ownership or contribution, other than in improving the readability of the work for modern readers. If the cross reference thing kills you, just use gnu ctags on the source directories and ctags -x for the line numbers. Here's the link to the posting: http://decuser.blogspot.com/2022/02/tweaked-version-of-lions-v6-source-code… - will

3 years, 2 months

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TUHS