TUHS September 2017

tuhs@tuhs.org

97 participants
84 discussions

Re: [TUHS] Line Terminators in Text Files [Was: Re: Why Pascal isNot My Favorite Programming Language - Unearthed!]

by Richard Tobin

> As I recall, the original definition of ASCII suggested that the > LF character was either "line feed" or "new line", and that if it > *was* new-line, it would be stand-alone. I have put a copy of the original ASCII standard (scanned images) at http://www.cogsci.ed.ac.uk/~richard/ascii.tar I don't remember where I got it from. -- Richard -- The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336.

6 years, 2 months

Re: [TUHS] Future Languages

by Richard Tobin

> So we have some source (that you can have as well, Apache license) > that handles not strings but vectors of strings (or structs or whatever). > > I need to write up how it works, it's sort of clever. It stores both > the size of the vector (always a power of 2) in part of the bits of the > first entry and the actual length in the other part. Because we can > express powers of two in very little space we can support both values > in a 32 bit unsigned with a max length of used space of around 134M. I have something similar. It allocates space for two ints (number allocated and used) at ((int *)array)[-1] and [-2]. Typical use is LTVectorAndInit(char *, names); while(...) LTVectorPush(names, s); for(i=0; i<LTVectorCount(names); i++) ... names[i] ...; LTVectorFree(names); -- Richard -- The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336.

6 years, 2 months

Re: [TUHS] It is time to modernise "groff"

by Doug McIlroy

> > p) Remove the '-a' option (the ASCII approximation output). > > I didn't even know this existed. Looking at what it spits out, I find > myself wondering what good it is. Is this for Unix troff compatibility? > For people who didn't even have glass TTYs and needed to imagine what > the typeset output would look like? Here's a classic use: Since groff is not WYSIWYG, the experimental cycle is long: edit - save - groff - view. In many cases that cycle can be short-circuited by typing straight into groff -a. doug

6 years, 2 months

Re: [TUHS] Introduction to {t,r,g}roff & co...

by Norman Wilson

Call me old-fashioned, but I still think the papers in Volume 2 of the Seventh Edition manual are a good straightforward start. There's a tutorial on troff, and papers introducing eqn, tbl, and refer. Norman Wilson Toronto ON

6 years, 2 months

Introduction to {t,r,g}roff & co...

by Grant Taylor

Hi, Can anyone point to an introduction to {t,r,g}roff / pic / tbl / etcetera? I've respected them for years and with all the latest discussions about them I'd like to try and learn something. Any pointers would be appreciated. -- Grant. . . . unix || die

6 years, 2 months

Re: [TUHS] Why Pascal is Not My Favorite Programming Language - Unearthed!

by Norman Wilson

Steve Johnson: I think of Alan Demer's comment: "There are two kinds of programming languages, those that make it easy to write good programs, and those that make it hard to write bad ones." ==== I'm (still) with Larry Flon on this one: There does not now, nor will there ever, exist a programming language in which it is the least bit hard to write bad programs. -- SIGPLAN Notices, October 1975, p. 16. There are certainly language that make it easier to avoid trivial mistakes, like buffer overruns and pointer botches, but the sort of nonsense Kernigan and Plaugher demonstrated and discussed about the same time in The Elements of Programming Style shows up in any language. I'm afraid I see that nearly any time I look in source code. To be fair, these days I rarely have the time to look at someone else's source code unless it's buggy, but it is nevertheless appalling what one finds in critical system software like boot environments and authentication code. There is no royal language to good programs. Programming well takes discipline and skill and experience. Languages like Pascal that prevent certain classes of sloppiness like overrunning arrays and string buffers may be better for teaching beginners, but only because that makes it easier to focus on the real issues, such as how to structure a program well and how to write clearly. I have yet to see evidence that that actually happens. Norman Wilson Toronto ON

6 years, 2 months

Re: [TUHS] Line Terminators in Text Files [Was: Re: Why Pascal is Not My Favorite Programming Language - Unearthed!]

by jnc＠mercury.lcs.mit.edu

> From: Chris Torek > termcap has entries for the number of NUL characters to insert after > carriage return. Actually, the stock terminal driver in V6 Unix (here: http://minnie.tuhs.org/cgi-bin/utree.pl?file=V6/usr/sys/dmr/tty.c if anyone wants to see the actual code; it's in ttyoutput()) had some pretty complex code to do just the right amount of delay (in clock ticks) for a large number of different motion contral characters (TAB, etc, in addition to LF and CR), and then uses the system timer to delay that amount of real time after sending such a character (see the very bottom of ttstart()). E.g. for a NL, it used the fact that it 'knew' which column the print head was in to calculate the exact return time. Clever, but alas, it did this by sticking 'characters' in the buffered output stream with the high bit set, and the delay required in the low 0177 bits, which the output start routine interpreted; as the code drolly notes, "thus (unfortunately) restricting the transmission path to 7 bits". Which was a real PITA recently when I tried to download a binary file to an LSI-11 from a V6 running in Ersatz-11! I had to tweak the TTY driver to allow 8-bit output... Noel

6 years, 2 months

Why Pascal is Not My Favorite Programming Language - Unearthed!

by arnold＠skeeve.com

Seek and ye shall find. Ask and ye shall receive. Brian Kernighan was kind enough to find for me everyone's favorite Computing Sceince Technical Report, CSTR 100, "Why Pascal is Not My Favorite Programming Language". Attached is the file and his macros. This will not immediately format using groff etc.; I hope to create a version that will, sometime in the next few weeks. In the meantime, Warren, please add to the archives when you are able. Enjoy! Arnold

6 years, 2 months

Follow-on to the Pascal/C/etc. discussion

by Jon Steinhart

Hi everybody. I'm new to this list as a side-effect of my question about the provenance of strcmp and the convention of returning <0, 0, >0. I had to learn Pascal as a freshman in college which was challenging coming from BTL knowing C. Kept wondering how Pascal could be used for anything useful. The answer that I later saw in industry was "by adding non-standard extensions". Language discussions often turn to the issue of whether programming languages should prevent programmers from making mistakes or whether that's the job of the programmer. This is, of course, independent of discussing the expressiveness of languages. I agree that a lot of "programming" today consists of trusting and bolting together random library functions. That's not me; I often work on safety critical devices and I'm not going to rely on libraries of unknown provenance when building a medical device that I make be hooked up to it someday. Years ago I inherited a project written in hodgepodge of programming languages including ruby. My first reaction to ruby was "Wow, how do I get some of what they're smoking because it's better than anything I have?" I eventually asked Ward Cunningham about it because he was working for ruby house AboutUs at the time. His answer went something like this: Jon, you're an engineer and you understand engineering. You know programming and programmers and understand programming. Then, there are the people with whom we entrust our confidential credit card data. That's what ruby is for. This nicely summarized the current state of affairs in which the most critical tasks are assigned to the least competent people. I see this as a management, business, and political problem which can't be solved by different languages. I have often made the statement that "I would never hire someone who had to use glibc in order to implement a singly-linked list." I get push-back such as "Oh, and people can create bugs rather than using the debugged library?" to which I glibly respond "debugged library like OpenSSL?" I am more than a little terrified by the "everybody must learn to code in high school movement". What they're learning is something at a level akin to the ruby example above. The goal is clearly to make "coding" a minimum wage job and to many the distinction between "coding" and engineering is lost. I've spoken with many kids in the "future engineer" category who are frustrated at the lack of depth in the curriculum. I'd summarize it as teaching people to program without teaching them anything about computers. Anyway, I have been volunteering to teach technology to kids for years as karmic payback to my BTL explorer scout advisors Carl Christensen, Heinz Lycklama, and Hans Lie. Not to mention all of the amazing people that I met there when my dedication to hitchhiking up the the Labs after school and talking people into signing me in turned into a series of summer jobs. I'm in the process of turning my class notes into a book. The goal of the book is to teach kids enough about computers that they can understand what their code is actually doing and why one can write better code with an understanding of the hardware and environment. The book is in the editing phase so it's beyond wholesale changes. But I'm curious as to what you all think should be in such a book as I'll find a way to wedge in anything important that I missed. Thanks, Jon

6 years, 2 months

Re: [TUHS] Why Pascal is Not My Favorite Programming Language - Unearthed!

by Diomidis Spinellis

And let's not forget Alan Perlis's: "A language that doesn't affect the way you think about programming, is not worth knowing." https://en.m.wikiquote.org/wiki/Alan_Perlis -------- Original message -------- From: Toby Thain Date:02/09/2017 18:00 (GMT+02:00) To: Dan Cross Cc: The Eunuchs Hysterical Society , quad Subject: Re: [TUHS] Why Pascal is Not My Favorite Programming Language - Unearthed! ... Finally, a favourite quote: "Programs must be written for people to read, and only incidentally for machines to execute" -- Hal Abelson https://twitter.com/old_sound/status/903919515884544000 --Toby > > - Dan C. >

6 years, 2 months

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TUHS September 2017