TUHS December 2020

tuhs@tuhs.org

56 participants
43 discussions

Knuth and Pascal (was "Were cron and at ...")

by M Douglas McIlroy

Off topic, but too much fun to pass up. >> You wrote your algorithm in Pascal, debugged it, and then rewrote it in your favourite language (in my case, ALGOL-W). > Now why didn't Don Knuth think of that for TeX? I'm glad he didn't. He might have written it in Mix. Knuth once said he didn't believe in higher-level languages. Of course he knew more about them than anybody else and was CACM's associate editor for the subject--like a minister who doesn't believe in God. Doug

4 years

Re: [TUHS] Were cron and at done at the same time? Or one before the other?

by jnc＠mercury.lcs.mit.edu

> From: "Theodore Y. Ts'o" > Having a clean architecture is useful in so far as it makes reduces > maintenance overhead and improves reliability. I would put it differently, hence my aphorism that: "the sign of great architecture is not how well it does the things it was designed to do, but how well it does things you never imagined it would be used for". I suppose you could say that reducing maintenance and improving reliability are examples of the natural consequences of that, but to me those are limited special cases of the more general statement. My sense is that systems decline over time because of what I call 'system cancer': as they are modified to do more and more (new) things, the changes are not usually very cleanly integrated, and eventually one winds up with a big pile. (Examples of this abound; I'm sure we can all think of several.) Noel

4 years

Happy birthday, Ada Lovelace and JFO!

by Dave Horsfall

Sorta relevant to both groups... Augusta Ada King-Noel, Countess of Lovelace (and daughter of Lord Byron), was born on this day in 1815; arguably the world's first computer programmer and a highly independent woman, she saw the potential in Charles Babbage's new-fangled invention. J.F.Ossanna was given unto us on this day in 1928; a prolific programmer, he not only had a hand in developing Unix but also gave us the ROFF series. Who'ld've thought that two computer greats would share the same birthday? -- Dave

4 years

Re: [TUHS] Were cron and at done at the same time? Or one before the other?

by jnc＠mercury.lcs.mit.edu

> From: Niklas Karlsson > Just consider Multics, or IBM's "Future System". Here's a nice irony for you: one of the key people in killing off FS was reported to me (by someone who should have known) to be Jerry Saltzer (of Multics fame). That wasn't the only time he did something like thst, either; when MIT leaned on him to take over Athena, the first thing he did was to take a lot of their ambitious system plans, and ditch them; they fell back to mostly 'off the shelf' stuff: pretty much vanilla 4.2, etc. Multics itself has an interesting story, quite different from the popular image among those who know little (or nothing) of it. The system, as it was when Honeywell pulled the plug on further generations of new hardware (in the mid-80's) was very different from the system as originally envisaged by MIT (in the mid-60's); it had undergone a massive amount 'experience-based evolution' during those 20 years. For instance, the original concept was to have a process per command (like Unix), but that was dropped early on (because Multics processes were too 'expensive'); they wound up going with doing commands with inter-segment procedure calls. (Which has the nice benefit that when a command faults, you can get dropped right into the debugger, with the failed instance there to look at.) If you read the Organick book on Multics, it describes a much different system: e.g. in Organick there's a 'linkage segment' (used for inter-segment pointers, in pure-code segments) per code segment, but in reality Multics, as distributed, used a single 'combined linkage segment' (which also contained the stack, also unlike the original design, where the stack was a separate segment). There were also numerous places where major sub-systems were re-implemeneted from scratch, with major changes (often great simplifications): one major re-do was the New Storage System, but that one had major new features (based on operationally-shown needs, like the 4.1/.2 Fast File System), so it's not a 'simplification' case. There's one I read about which was much simpler the second time it was implemented, I think it was IPC? Noel

4 years

Re: [TUHS] Were cron and at done at the same time? Or one before the other?

by John Foust

At 09:40 AM 12/9/2020, Clem Cole wrote: >My own take on this is what I call "Cole's Law"Â Â Simple economics always beats sophisticated architecture. I thought that was finely sliced cabbage with a tart salad dressing. - John

4 years

Were cron and at done at the same time? Or one before the other?

by ron minnich

When I got into Unix in 1976 cron and at were both there. I got to wondering for no particular reason which came first -- I had always assumed cron, but ...? Anyone know?

4 years

The origin of Goto considered harmful?

by Bakul Shah

Last night I stumbled upon this speech by Doug McIlroy at Dijkstra's retirement banquet @ UT Austin where he tells the story of his first encounter with EWD and the origins of programming without goto.... Given that we recently had a discussion on "Goto considered harmful", you all may enjoy it. Make sure you watch the start of part 10 as well as that is where the story ends. https://youtu.be/5OUPBwrufKA?list=PL328C7EFFC1F41674&t=326

4 years

Command name of the B compiler; One letter command names

by markus schnalke

Hoi, I'm wondering what the name of the B compiler was. Doug's ``Unix Reader'' lists: 1 2 3 4 5 6 7 8 9 + + + . . . . . . b compile b program . . . . . + + + + bc arbitrary-precision arithmetic language Via Wikipedia I found a scan of the ``Users' Reference to B'', a technical memorandum by Ken, dated 1972-01-07 (which is between the releases of the 1st and 2nd Edition). https://web.archive.org/web/20150317033259/https://www.bell-labs.com/usr/dm… There on page 25: 10.0 Usage Currently on UNIX, there is no B command. The B compiler phases must be executed piecemeal. The first phase turns a B source program into an intermediate language. /etc/bc source interm The next phase turns the intermediate language into assembler source, at which time the intermediate language can be removed. /etc/ba interm asource rm interm The next phase assembles the assembler source into the object tile a.out. After this the a.out file can be renamed and the assembler source file can be removed. as asource mv a.out object rm asource The last phase loads the various object files with the necessary libraries in the desired order. ld object /etc/brtl -lb /etc/bilib /etc/brt2 Now a.out contains the completely bound and loaded program and can be executed. a.out A canned sequence of shell commands exists invoked as follows: sh /usr/b/rc x It will compile, convert, assemble and load the file x.b into the executable file a.out. It lists /etc/bc, as a command to convert into the intermediate language, and /etc/ba, to convert the intermediate language into assembler source, but lists no `b' command. The wrapper script is /usr/b/rc. Can someone clarify? I came to this question because I was looking for one letter commands. I always thought them to be a reserved namespace for the user ... Any background on that topic is appreciated as well. ;-) meillo

4 years

Re: [TUHS] The UNIX Command Language (1976)

by M Douglas McIlroy

There's a back story. The paper appears in the proceedings of a conference held in London in 1973, a few months after the advent of pipes. While preparing the presentation, Ken was inspired to invent and install the pipe operator. His talk wouldn't have been nearly as compelling had it been expressed in the original pipeline syntax (for which I take the blame). References to eqn (v5), bc (v6), and ratfor (v7) obviously postdate the London conference. Ken must have edited--or re-created--the transcript for the proceedings sometime after v6 (May, 1975). Bibliographic citations are missing. Can they be resurrected? Reference 137, about Unix itself, probably refers to a presentation by Ken and Dennis at SOSP in January1973. Alas, only an abstract of the talk appears in the conference proceedings. But the abstract does contain the potent and often-repeated sentence, "It offers a number of features seldom found even in larger operating systems, including ... inter-process IO ..." The talk--in Yorktown Heights--was memorable, and so was a ride to the same place in Ken's 'vette. (I can't recall whether the two happened on the same occasion.) Given that the talk at SOSP preceded the talk in London, and that the Unix manual was widely distributed by (1976) when the revised London talk was printed, the claim that "The Unix command language" was the first publication of Unix seems hyperbolic. In no way, though, does this detract from the inherent interest of the paper. Doug

4 years

Apple IIe Unix?

by Will Senn

Hi All, So, I'm about to get my very own Apple IIe and while it's an incredibly versatile machine for assembly language and hardware hackery, I'm not aware of any Unices that run on the machine, natively. Does anybody know of any from back in the day? It's got a 65c02 processor and somewhere around 128k of RAM, but it's also pretty expandable w/7 slots and a huge amount of literature about how to do stuff w/those slots. Thanks, Will -- GPG Fingerprint: 68F4 B3BD 1730 555A 4462 7D45 3EAA 5B6D A982 BAAF

4 years

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TUHS December 2020