TUHS

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Space Travel, was New: The Earliest UNIX Code

by Doug McIlroy

> 10-36-55.pdf user-mode programs: pool game This game, written by ken, used the Graphic 2. One of its earliest tests--random starting positions and velocities on a frictionless table with no collision detection--produced a mesmerizing result. This was saved in a program called "weird1", which was carried across to the PDP11. Weird1 was a spectacular accidental demonstration of structure in pseudo-random numbers. After several minutes the dots representing pool balls would evanescently form short local alignments. Thereafter from time to time ever-larger alignments would materialize. Finally in a grand climax all the balls converged to a single point. It was stunning to watch perfect order emerge from apparent chaos. One of my fondest hopes is to see weird1 revived. Doug

5 years, 6 months

Design of the AT&T assembly syntax

by Robert Clausecker

Some time ago, I wrote a piece [1] about the design of the AT&T assembler syntax. While I'm still not quite sure if everything in there is correct, this explanation seemed plausible to me; the PDP-11 assembler being adapted for the 8086, then the 80386 and then ELF targets, giving us today's convoluted syntax. The one thing in this chain I have never found is an AT&T style assembler for x86 before ELF was introduced. Supposedly, it would get away without % as a register prefix, thus being much less obnoxious to use. Any idea if such an assembler ever existed and if yes where? I suppose Xenix might have shipped something like that. The only AT&T syntax assemblers I know today are those from Solaris, the GNU project, the LLVM project, and possibly whatever macOS ships. Are there (or where there) any other x86 AT&T assemblers? Who was the first party to introduce this? Yours, Robert Clausecker [1]: https://stackoverflow.com/a/42250270/417501 -- () ascii ribbon campaign - for an 8-bit clean world /\ - against html email - against proprietary attachments

5 years, 6 months

Design of the AT&T assembly syntax

by Robert Clausecker

5 years, 6 months

Design of the AT&T assembly syntax

by Alexander Voropay

Robert Clausecker <fuz(a)fuz.su>wrote: > The one thing in this chain I have never found is an AT&T style > assembler for x86 before ELF was introduced. There were alot of AT&T codebase ports to x86 architecture except Xenix: Microport, INTERACTIVE, Everex, Wyse e.t.c. using AT&T x86 syntax. I've tried Microport SystemV /386 (SysV R3.2). It uses COFF as format for executables: See: http://www.vcfed.org/forum/showthread.php?67736-History-behind-the-disk-ima… (Rather interesting kernel ABI/Call convention) and https://gunkies.org/wiki/Unix_SYSVr3 There were also SystemV R2 to i286 ports i.e.: https://gunkies.org/wiki/Microport_System_V with a.out binary format.

5 years, 6 months

Re: [TUHS] UNIX: A History and a Memoir by Brian W. Kernighan is

by Norman Wilson

Bother: Here's a good pictore of G R herself, with what I believe to be at least a second-generation badge. Forgot to paste in the URL. Here it is: http://www.peteradamsphoto.com/g-r-emlin/

5 years, 6 months

Re: [TUHS] UNIX: A History and a Memoir by Brian W. Kernighan is

by Norman Wilson

Mary Ann Horton: I'm enjoying bwk's book very much, but it has me wondering. There are two stories I've heard that supposedly occurred at Murray Hill, but he didn't include them. ==== You can't expect every story to be there. The book would be too heavy to lift! Could the `monkey picture on a badge' story be that of G. R. Emlin's badge? She was a gremlin doll, not a monkey, but it would be reasonable to mistake the former for the latter. Here's a good pictore of G R herself, with what I believe to be at least a second-generation badge. The original badge was an old-style Bell Labs one with a green border; I forget whether that meant contractor or something else, but a regular MTS badge was blue-bordered at the time. Norman Wilson Toronto ON

5 years, 6 months

UNIX Backslash History

by Doug McIlroy

> What is the special meaning of using / as directory partition in UNIX? And \ as the escape character. \ came from Multics. The first day Multics ran at Bell Labs Bob Morris famously typed backslash-newline at the login prompt and crashed the system. Multics had a hierarchical file system, too, but I don't recall how pathnames were punctuated. Doug

5 years, 6 months

Re: [TUHS] UNIX Backslash History

by jnc＠mercury.lcs.mit.edu

> From: Charles Anthony >> I think it was >user_dir_dir>Group>User, wasn't it? > user_dir_dir>Project>User Oh, right. Too many years spent on Unix! :-) > "Names" are aliases, similar to soft links I feel like they are more similar to hard links; they belong to a segment, and if the name is given to another segment, and the original segment has only that name, it goes away. (See the discussion under "add_name" in the MPM 'Commands and Active Fuinctions'). Also, Multics does real soft links (too), so names can't be soft links! :-) Noel

5 years, 6 months

My EuroBSDCon talk

by Warner Losh

My talk has been posted. https://youtu.be/FTlzaDgzPY8 Thanks to everyone who helped make it better. Warner P.s. this may be a duplicate email... I had domain issues when I sent it before...

5 years, 6 months

Re: [TUHS] UNIX Backslash History

by jnc＠mercury.lcs.mit.edu

> From: Charles Anthony > /home/CAnthony I think it was >user_dir_dir>Group>User, wasn't it? I seem to remember my homedir on MIT-Multics was >udd>CSR>JNChiappa? And I wonder if the 'dd' directory on PDP-7 Unix owe anything to 'udd'? Getting back to the original query, I'm wondering if '/' was picked as it wasn't shifted, unlike '>'? Noel

5 years, 6 months

My EuroBSDCon Unix Talk is up

by Warner Losh

https://www.youtube.com/watch?v=FTlzaDgzPY8 has my EuroBSDcon unix talk that everybody here was so kind to assist me on. Warner

5 years, 6 months

Two Unix50 Videos

by Warren Toomey

from the Nokia event are up: https://www.youtube.com/watch?v=dUt3L3fLFt4 Unix Today and Tomorrow: Future of Compute & Platforms: The Kernel https://www.youtube.com/watch?v=lz3GADLe__M The origin of Unix panel session Cheers, Warren

5 years, 7 months

UNIX Backslash History

by Caipenghui

Hello everyone, What is the special meaning of using / as directory partition in UNIX? And \ as the escape character. Caipenghui

5 years, 7 months

Re: [TUHS] How to do differential/integral on a PDP-7, was: Space Travel

by Dave Horsfall

On Mon, 21 Oct 2019, Andrew Hume wrote: > the gt40??? oh my lord! good job i am en route to the bell labs 50th > anniversary. > its been a long time since i heard the name “Dave Horsfall”! Yep :-) Although now retired, I'm still active in Unix projects. -- Dave

5 years, 7 months

Re: [TUHS] Space Travel, was New: The Earliest UNIX Code

by Doug McIlroy

I was about to add a footnote to history about how the broad interests and collegiality of Bell Labs staff made Space Travel work, when I saw that Ken beat me to telling how he got help from another Turing Award winner. > while writing "space travel," > i could not get the space ship integration > around a planet to keep from either gaining or > losing energy due to floating point errors. > i asked dick hamming if he could help. after > a couple hours, he came back with a formula. > i tried it and it worked perfectly. it was some > weird simple double integration that self > corrected for fp round off. as near as i can > ascertain, the formula was never published > and no one i have asked (including me) has > been able to recreate it. If I remember correctly, the cause of Ken's difficulty was not roundoff error. It was discretization error in the integration formula--probably f(t+dt)=f(t)+f'(t)dt. Dick saw that the formula did not conserve energy and found an alternative that did.

5 years, 7 months

What was your "Aha, Unix!" moment?

by Warren Toomey

All, we had another dozen TUHS suscribers to the list overnight. Welcome. A reminder that we're here to discuss Unix Heritage, so I'll nudge you if the conversation goes a bit off-topic. So I'll kick off another thread. What was your "ahah" moment when you first saw that Unix was special, especially compared to the systems you'd previously used? Mine was: Oh, I can: + write a simple script + to edit a file on the fly + with no temporary files (a la pipes) + AND I can change the file suffix and the system won't stop me! I was using TOPS-20 beforehand. Cheers, Warren

5 years, 7 months

PDP-7 UNIX filesystem

by Angelo Papenhoff

DMR explained how PDP-7 UNIX was used in "The Evolution of the Unix Time-sharing System" but having played with it myself, I stumbled in a couple of cases and found it a bit awkward to use. Maybe someone (ken and doug?) can shed some light on "elaborate set of conventions" that dmr mentioned. My questions are these: you cannot execute a program if you're in a directory you can't write into. I asked Warren about this when I first tried pdp7 unix and he explained it to me: the shell creates a link to the binary and executes it. If it can't write into the current directory, it fails to create the link and hence can't execute the program. How was this handled in practice? did users have write permissions on all directories? did you just stay in your directory all the time? . and .. Was this introduced first with PDP-11 unix or did the convention start on the PDP-7 already? It certainly seems to be the case with . but how about ..? the dd directory seems to take on the role of a sort of root directory and the now discovered program pd actually creates a file .. (haven't tried to understand what it does though yet) What does dd stand for, dotdot? directory directory? aap

5 years, 7 months

Re: [TUHS] PDP-7 UNIX file systam

by Doug McIlroy

> As noted in the jargon file, the dd(1) syntax is deliberately reminiscent > of the DD statement in IBM JCL. This was presumably a joke That is certainly true and reflects its major early usage to prepare tapes to carry to other systems. Though I haven't use dit in ages, I recall that the joke was so fully engtained that the command was more likely to be written "dd ifile=x ofile=y" than "dd <x >y" Doug

5 years, 7 months

Re: [TUHS] PDP-7 UNIX filesystem

by jnc＠mercury.lcs.mit.edu

> From: Abhinav Rajagopalan > I only now realized that only mknod existed, up until a long time, only > later on with the GNU coreutils did mkdir as a command come into > existence. Huh? See: https://minnie.tuhs.org//cgi-bin/utree.pl?file=V6/usr/man/man1/mkdir.1 (And probably before that, that was the quickest one to find?) Maybe that was a typo for 'mkdir as a system call'? (I recall having to do a fork() to execute 'mkdir', back when.) But 4.2 had mkdir(). Noel

5 years, 7 months

UNIX: A History and a Memoir by Brian W. Kernighan is now out

by Naveen Nathan

It can be purchased here: https://www.amazon.com/dp/1695978552/ - Naveen

5 years, 7 months

Re: [TUHS] What was your "Aha, Unix!" moment?

by jnc＠mercury.lcs.mit.edu

> From: Sean Dwyer > chdir seems to be a syscall in 7 (sys4.c) It's been a system call forever, see e.g.: https://minnie.tuhs.org//cgi-bin/utree.pl?file=V1/man/man2/chdir.2 (And the working dir was a property of the process, not data in the shell.) Noel

5 years, 7 months

Re: [TUHS] What was your "Aha, Unix!" moment?

by Norman Wilson

Bakul Shah: Being an OS student I had read "The Unix Timesharing System" paper by Ritchie and Thompson and had wanted to use Unix years before I actually had the chance. I don't remember an "Aha!" moment but I took to it like a duck to water. Most everything felt just so comfortable and right. It was very much as I had imagined it to be. ===== That's more or less what it was like to me. Not so much an aha! moment, more just a feeling of coming home. It took a while to understand the different way things worked in UNIX (I had previously used TOPS-10 for several years) but as it all sank in it felt more and more right. C felt the same way. It took me a while to grok the pointer syntax (I had done a lot of MACRO-10 programming so I certainly understood the concept, just not how it fit into the higher- level language), but things like the three-clause condition in for so that all control for a loop could be in one place were just magically right. I don't think I read the CACM paper before I touched UNIX, but I had read both editions of Software Tools, so my brain was perhaps pre-seeded with some of the ideas. Norman Wilson Toronto ON

5 years, 7 months

Re: [TUHS] What was your "Aha, Unix!" moment?

by jnc＠mercury.lcs.mit.edu

> From: Warren Toomey <wkt(a)tuhs.org> > But wasn't "chdir" built into the PDP-7 Unix shell? No. See "The Evolution of the Unix Time-sharing System", in section "Process control". Also, the old 'cd' had different syntax than today's (since there was no notion of a pathname in the earliest Unix); it took instead a list of directories (e.g. "cd dd ken"). Noel

5 years, 7 months

Re: [TUHS] TUHS Digest, Vol 47, Issue 31

by Will Senn

On 10/21/19 9:05 AM, tuhs-request(a)minnie.tuhs.org wrote: > Message: 17 > Date: Mon, 21 Oct 2019 08:10:00 -0400 (EDT) > From:jnc@mercury.lcs.mit.edu (Noel Chiappa) > To:tuhs@minnie.tuhs.org > Cc:jnc@mercury.lcs.mit.edu > Subject: Re: [TUHS] What was your "Aha, Unix!" moment? > Message-ID:<20191021121000.34E3B18C09F(a)mercury.lcs.mit.edu> > > > From: Warren Toomey<wkt(a)tuhs.org> > > > But wasn't "chdir" built into the PDP-7 Unix shell? > > No. See "The Evolution of the Unix Time-sharing System", in section "Process > control". > > Also, the old 'cd' had different syntax than today's (since there was no notion > of a pathname in the earliest Unix); it took instead a list of directories (e.g. > "cd dd ken"). > > Noel > Wanna have some fun? chdir system then try to find your way back 'home'... v0's subdirectories suck. -- GPG Fingerprint: 68F4 B3BD 1730 555A 4462 7D45 3EAA 5B6D A982 BAAF

5 years, 7 months

Re: [TUHS] Vaxen, my children...

by Pat Barron

On the copy of this story that appears here: http://crash.com/fun/texts/vaxen-dont.html it is atrributed as such: 'The author of this piece is Jack Harvey, harvey(at)eisner.decus.org, and it was originally published under the title "The Immortal Murderer" on January 18th, 1989 on DECUServe, the DECUS member bulletin board.' --Pat.

5 years, 7 months

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