TUHS

tuhs@tuhs.org

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6532 discussions

by Will Senn

Does anyone know if the image http://www.tuhs.org/Archive/Distributions/Research/Dennis_v6/v6root.gz is somehow bootable as-is? I wasn't able to figure out how to get it to boot, so I went on a quest to make it bootable. Here's what I did - let me know if this was overkill or misguided. Basically, I downloaded the known bootable v6 distribution tape from Wellsch directory in TUHS. I then extracted 101 blocks from the image (tmrk, a bootblock, and who knows what else, but seriously what else is on those first 100 blocks?), converted it to a simh compatible tape format, and booted a simh generic pdp11/40 with my new little boot tape and Dennis's root disk attached. I used tmrk to copy the bootstrap from my little tape to Dennis's root disk (am I clobbering anything important?). Then voila - it was bootable :)! I could have done it straight off Ken's tape (after converting it to a simh tape format), but I wanted to keep the little tape image around for use in other contexts. Details for the curious are here: https://decuser.github.io/bootable-tape-v6.txt I thought the Ken Wellsch tape was basically the same as the Dennis Ritchie disks, but now I'm not so sure - on Ken's tape, it boots to: @rkunix mem = 1035 RESTRICTED RIGHTS Use, duplication or disclosure is subject to restrictions stated in Contract with Western Electric Company, Inc. # on Dennis' it boots to: @rkunix mem = 1036 # Makes me curious to see what else is different. Maybe Dennis's was prior to preparing an official distro where the rights were added to the kernel? Will -- GPG Fingerprint: 68F4 B3BD 1730 555A 4462 7D45 3EAA 5B6D A982 BAAF

7 years, 7 months

Re: [TUHS] 80 columns ...

by Norman Wilson

Nemo: And for that reason, I have never used Python. (I have a mental block about that.) ==== I used to feel the same way. A few years ago I held my nose and jumped in. I'm glad I did; Python is a nifty little language that, now I know it, hits a sweet spot twixt low-level C and high-level shell and awk scripts. Denoting blocks solely by indentation isn't at all bad once you do it; no worse than adapting from do ... end to C's {}. What still bugs me about Python: -- It is unreasonably messy to give someone else a copy of a program composed of many internal modules. Apparently you are expected to give her a handful of files, to be installed in some directory whose name must be added to the search path in every Python source file that imports them. I have come up with my own hacky workaround but it would be nice if the language provided a graceful way to, e.g., catenate multiple modules into a single source file for distribution. -- I miss C's style of for loop, though not often. (Not quite everything can be turned into a list or an iterator.) -- I miss one particular case of assigment having a value: that of while ((val = function()) != STOP) do something with val Again, there are clunky ways to work around this. As for 80 columns, I'm firmly in the camp that says that if you need a lot of indentation you're doing it wrong. Usually it means you should be pulling the details out into separate functions. Functions that run on for many, many lines (once upon a time it was meaningful to say for many pages, but no longer) are just as bad, for the same reason: it's hard to read and understand the code, because you have to keep so many details in your head at once. Likewise for excessive use of global variables, for that matter, a flaw that is still quite common in C code. Having to break an expression or a function call over multiple lines is more problematic. It's clearer not to have to do that. It helps not to make function or variable names longer than necessary, but one can carry that too far too. Style and clarity are hard, but they are what distinguishes a crap hack programmer from a good one. Norman Wilson Toronto ON (Sitting on the lower level of a train in Texas, not on a pedestal)

7 years, 7 months

80 columns ...

by ron minnich

So, 80 column folks, would you find this a(b, c, d) more readable than a(b,c,d) (this is a real example, with slightly shortened names) would you have code review software that automatically bounces out lines that are 82 columns wide? How far does this go? I do recall 80 column monitors, but I started on 132 column decwriter IIs and hence have never had sympathy for 80 columns. It's weird that so many punched-card standards are required in our code bases now (see: Linux). moving away from serious ... (look for Presottos' I feel so liberated ...) http://comp.os.plan9.narkive.com/4W8iThHW/9fans-acme-fonts

7 years, 7 months

finding help in v7 in 1980

by Will Senn

Hi, Everyone on the list is well aware that running V7 in a modern simulator like SIMH is not a period realistic environment and some of the "problems" facing the novice enthusiast are considerably different from those of the era (my terminal is orders of magnitude faster and my "tape" is a file on a disk). However, many of the challenges facing someone in 1980, remain for the enthusiast, such as how to run various commands successfully and how devices interoperate with unix. Of course, we have do resources and some overlapping experience to draw on - duckduckgo (googleish), tuhs member experience, and exposure to modern derivatives like linux, macos, bsd, etc. We also have documentation of the system in the form of the Programmer's Guide - as pdfs and to some degree as man pages on the system (haven't found volume 2 documentation on the instance). My question for you citizens of that long-ago era :), is this - what was it like to sit down and learn unix V7 on a PDP? Not from a hardware or ergonomics perspective, but from a human information processing perspective. What resources did you consult in your early days and what did the workflow look like in practical terms. As an example - today, when I want to know how to accomplish a task in modern unix, I: 1. Search my own experience and knowledge. If I know the answer, duh, I know it. 2. Decide if I have enough information about the task to guess at the requisite commands. If I do, then man command is my friend. If not, I try man -k task or apropos task where task is a one word summary of what I'm trying to accomplish. 3. If that fails, then I search for the task online and try what other folks have done in similar circumstances. 4. If that fails, then I look for an OS specific help list (linux-mint-help, freebsd forums, etc), do another search there, and post a question. 5. If that fails, or takes a while, and I know someone with enough knowledge to help, I ask them. 6. I find and scan relevant literature or books on the subject for something related. Repeat as needed. Programming requires some additional steps: 1. look at source files including headers and code. 2. look at library dependencies 3. ask on dev lists but otherwise, is similar. In V7, it's trickier because apropos doesn't exist, or the functional equivalent man -k, for that matter and books are hard to find (most deal with System V or BSD. I do find the command 'find /usr/man -name "*" -a -print | grep task' to be useful in finding man pages, but it's not as general as apropos. So, what was the process of learning unix like in the V7 days? What were your goto resources? More than just man and the sources? Any particular notes, articles, posts, or books that were really helpful (I found the article, not the book, "The Unix Programming Environment" by Kernighan and Mashey, to be enlightening https://www.computer.org/csdl/mags/co/1981/04/01667315.pdf)? Regards, Will

7 years, 7 months

Version 8 will never come out!

by Will Senn

Reading in the AUUGN vol 1 number 4, p. 15 in letter dated April 5, 1979, from Alistair Kilgour, Glasgow writing to Ian Johnstone, New South Wales about a Unix meeting in the U.K. at University of Kent at Caterbury (150 attended the meeting) with Ken Thompson and Brian Kernighan... Two paragraphs that I found interesting and fun: Most U.K. users were astonished to hear that one thing which has _not_ changed in Version 7 is the default for "delete character" and "delete line" in the teletype handler - we thought we'd seen the last of # and @! What was very clear was that version 7 is a "snapshot" of a still developing system, and indeed neither speaker seemed quite sure of when the snapshot was taken or exactly what it contained. The general feeling among users at the meeting was that the new tools provided with version 7 were too good to resist (though many had doubts about the new Shell). We were however relieved by the assurance that there would _never_ be a version 8! ... Finally a quotation, attributed to Steve Johnstone, with which Brian Kernighan introduced his excellent sales campaign for Unix on the first day of the conference: " Using TSO is like kicking a dead whale along the beach". Unix rules. ... I knew it, it's not just me - those pesky # and @ characters were and still are really annoying! Oh, and never say never. Unix does rule :). Will -- GPG Fingerprint: 68F4 B3BD 1730 555A 4462 7D45 3EAA 5B6D A982 BAAF

7 years, 7 months

origins of void*

by Paul Ruizendaal

I’m trying to understand the origins of void pointers in C. I think they first appeared formally in the C89 spec, but may have existed in earlier compilers. Of course, as late as V7 there wasn’t much enforcement of types and hence no need for the void* concept and automatic casting. I suppose ‘lint’ would have flagged it though. In the 4BSD era there was caddr_t, which I think was used for pretty much the same purposes. Did ‘lint’ in the 4BSD era complain about omitted casts to and fro’ caddr_t? Background to my question is research into the evolution of the socket API in 4.1x BSD and the persistence of ‘struct sockaddr *’ in actual code, even though the design papers show an intent for ‘caddr_t’ (presumably with ‘void*’ semantics, but I’m not sure). Paul

7 years, 7 months

Re: [TUHS] finding help in v7 in 1980

by jnc＠mercury.lcs.mit.edu

> From: Will Senn > what was it like to sit down and learn unix V7 on a PDP? ... What > resources did you consult in your early days Well, I started by reading through the UPM (the 8-section thing, with commands in I, system calls in II, etc). I also read a lot of Unix documentation which came as larger documents (e.g the Unix Intro, C Tutorial and spec, etc). I should point out that back then, this was a feasible task. Most man pages were really _a_ page, and often a short one. By the end of my time on the PWB1 system, there were about 300 commands in /bin (which includes sections II, VI and VIII), but a good chunk (I'd say probably 50 or more) were ones we'd written. So there were not that many to start with (section II was maybe 3/4" of paper), and you could read the UPM in a couple of hours. (I read through it more than once; you'd get more retained, mentally, on each pass.) There were no Unix people at all in the group at MIT which I joined, so I couldn't ask around; there were a bunch in another group on the floor below, although I didn't use them much - mostly it was RTFM. Mailing lists? Books? Fuhgeddaboutit! My next step in learning the kernel was to start reading the sources. (I didn't have access to Lyons.) I did an 'cref' of the entire system, and transferred the results to a large piece of paper, so I could see who was calling who in the kernel. > What were your goto resources? More than just man and the sources? That's all there was! I should point out that reading the sources to command 'x' taught you more than just how 'x' worked - you saw how people interacted with the kernel, what it could do, etc, etc. Noel

7 years, 7 months

Re: [TUHS] margins and indenting, and arbitrary c rules

by jnc＠mercury.lcs.mit.edu

> I'd been moving in this direction for a while Now that I think about it, I may have subconciously absorbed this from Ken's and Dennis' code in the V6 kernel. Go take a look at it: more than one level of indent is quite rare in anything there (including tty.c, which has some pretty complex stuff in it). I don't know if this was subconcious but deliberate, or concious, or just something they did for other reasons (e.g. typing long lines took too long on their TTY's :-), but it's very noticeable, and consistent. It interesting that both seem to have had the same style; tty.c is in dmr/, so presumably Dennis', but the stuff in ken/ is the same way. Oh, one other trick for simplifying code structure (which I noticed looking through the V6 code a bit - this was something they _didn't_ do in one place, which I would have done): if you have if (<condition>) { <some complex piece of code> } <implicit return> } invert it: if (<!condition>) return; <some complex piece of code> } That gets that whole complex piece of code down one level of nesting. Noel

7 years, 7 months

Re: [TUHS] TUHS Digest, Vol 24, Issue 43

by David

I sometimes put the following in shell scripts at the beginning > /tmp/foo 2>/tmp/foo_err Drives some folks up the wall because they don’t get it. David > On Nov 8, 2017, at 3:21 PM, tuhs-request(a)minnie.tuhs.org wrote: > > From: Dave Horsfall <dave(a)horsfall.org> > To: The Eunuchs Hysterical Society <tuhs(a)tuhs.org> > Subject: Re: [TUHS] pre-more pager? > Message-ID: <alpine.BSF.2.21.1711091019480.4766(a)aneurin.horsfall.org> > Content-Type: text/plain; charset=US-ASCII; format=flowed > > On Wed, 8 Nov 2017, Arthur Krewat wrote: > >> head -20 < filename > > Or if you really want to confuse the newbies: > > < filename head -20

7 years, 7 months

"hacker caught" paper

by Steve Simon

I am trying to find a paper. It was written at Bell Labs, I thought by Bill Cheswick (though I cannot find it in his name), entitled something like: "A hacker caught, and examined" A description of how a hacker got into Bell labs, and was quarintined on a single workstation whilst the staff watched what they did. Does this ring any bells? Anyone have a link? I know about the Cuckoo's egg, but this was a paper, in troff and -ms macros as I remember, not a book. Thanks, -Steve

7 years, 7 months

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TUHS