TUHS October 2019

tuhs@tuhs.org

120 participants
86 discussions

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

4 years, 5 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

4 years, 5 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

4 years, 5 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

4 years, 5 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

4 years, 5 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

4 years, 5 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

4 years, 5 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

4 years, 6 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

4 years, 6 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.

4 years, 6 months

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TUHS October 2019