TUHS

tuhs@tuhs.org

31 participants
6541 discussions

by norman＠oclsc.org

Some of us have, literally for decades, been dealing with wtmp by rolling it weekly or monthly or quarterly or whatever, letting cron run something like cd /usr/adm # that's how long I've been doing this! umask 022 >wtmp.new ln wtmp wtmp.prev mv wtmp.new wtmp # also so long ago there was no seq(1) nums=`awk 'BEGIN {for (i = 12; i >= 0; i--) print i; exit}'` for i in $nums; do inext=`expr $i + 1` if [ -f wtmp.$i ]; then mv wtmp.$i wtmp.$inext fi done mv wtmp.prev wtmp.0 This really isn't rocket science. It isn't even particularly interesting UNIX history. Can we move on to something that IS interesting? Here are some things I find more interesting: 1. utmp came before wtmp: utmp(V) appears in the First Edition manual, wtmp(V) only in the Second. Apparently interest in who else is logged in right now predated interest in who has logged in recently. 2. Both files started out in /tmp. wtmp is first said to be in /usr/adm instead in the Fifth Edition manual, utmp in /etc in the Sixth. 3. The names /tmp/utmp and /tmp/wtmp appear to have been issued by the Department of Redundancy Department. I think it quite likely that Ken and Dennis would have been familiar with that joke once the recording containing it was issued in mid-1970, but I don't know whether utmp existed in some form before that. I see no sign of it in the fragments of PDP-7 source code we have (in particular init doesn't seem to use it), but what about later PDP-7 or very early PDP-11 code predating the late-1971 First Edition manual? Norman Wilson Toronto ON Not Insane

4 years

Binary log files

by John Cowan

As long ago as the 7th Edition, several binary log files were maintained: the file generated by acct(2) (one record per process) and the utmp and wtmp files (one record per login). Both of these are defined by structs in .h files, so they are definitely not portable (int sizes, endianism, etc.)

4 years

[tuhs] Dennis Ritchie's couch

by Nelson H. F. Beebe

The last article of the latest issue of the Communications of the ACM that appeared electronically earlier today is a brief interview with this year's ACM Turing Award winners, Al Aho and Jeff Ullman. The article is Last byte: Shaping the foundations of programming languages https://doi.org/10.1145/3460442 Comm. ACM 64(6), 120, 119, June 2021. and it includes a picture of the two winners sitting on Dennis Ritchie's couch. I liked this snippet from Jeff Ullman, praising fellow list member Steve Johnson's landmark program, yacc: >> ... >> At the time of the first Fortran compiler, it took several >> person-years to write a parser. By the time yacc came around, >> you could do it in an afternoon. >> ... ------------------------------------------------------------------------------- - Nelson H. F. Beebe Tel: +1 801 581 5254 - - University of Utah FAX: +1 801 581 4148 - - Department of Mathematics, 110 LCB Internet e-mail: beebe(a)math.utah.edu - - 155 S 1400 E RM 233 beebe(a)acm.org beebe(a)computer.org - - Salt Lake City, UT 84112-0090, USA URL: http://www.math.utah.edu/~beebe/ - -------------------------------------------------------------------------------

4 years

Re: [TUHS] The Unix shell: a 50-year view

by Jon Steinhart

Wow. This is a terrible paper. It's full of of incorrect, unsubstiantiated, and meaningless statements. It's so bad in my opinion that I'm not sorry that I dropped my ACM membership a while ago. These folks really needed an editor. The paper annoys me so much that I've decided to write a lengthy note to the authors which I'll post here once I'm done. Jon

4 years

Disassemblers

by Henry Bent

>From what I can gather the only way to reasonably examine the disassembly of a program in the early days of Unix was adb. Is this true? Was there a way to easily produce a full disassembly? I'll confess to being fairly ignorant of adb use since I always had dbx or the equivalent available. The first tool I'm aware of to purposefully/primarily produce a full listing is MIPS dis (ca. 1986?) but there must have been something before that for other systems, no? -Henry

4 years

pointer disambiguation (was Re: Disassemers)

by Paul Winalski

On 7/1/21, scj(a)yaccman.com <scj(a)yaccman.com> wrote: > When PCC came along and started running on 32-bit machines, I started > thinking about algorithms for optimization. A problem that I had no > good solution for could be illustrated by a simple piece of code: > > x = *p; > > y = *q; > > q gets changed > > *q = z; > > The question is, do I need to reload x now because q might have been > changed to point to the same place as p? Yes, this is a very well-known problem in scalar optimization in compiler engineering. It's called pointer disambiguation and is part of the more general problem of data flow analysis. As you observed, getting it wrong can lead to very subtle and hard-to-debug correctness problems. In the worst case, one has to throw out all current data flow analysis of global and currently active local variables and start over. In your example, the statement "*q = z" may end up forcing the compiler to toss out all data flow information on x and z (and maybe p and q as well). If q could possibly point to x and x is in a register, the assignment forces x to be reloaded before its next use. Ambiguous pointers prohibit a lot of important optimizations. This problem is the source of a lot of bugs in compilers that do aggressive optimizations. Fortunately a bit of knowledge of just how "q gets changed" can rescue the situation. In strongly-typed languages, for example, if x and z are different data types, we know the assignment of z through q can't affect x. We also know that the assignment can't affect x if x and z have disjoint scopes. The 'restrict' keyword in C pointer declarations was added to help mitigate this problem. Some compilers also have a command line option that allows the user to say, "I solemnly swear that I won't do this sort of thing". -Paul W.

4 years

Re: [TUHS] Using printf from Assembly Language in V6, and db.

by jnc＠mercury.lcs.mit.edu

> From: Paul Riley <paul(a)rileyriot.com> >> (I wrote a note, BITD, explaining how all this worked; I'll upload it >> to the CHWiki when I get a chance.) Now here: https://gunkies.org/wiki/PDP-11_C_stack_operation along with simple examples of args and auto variables, which are both referenced via the FP. > As a non-C consumer of printf, should I point R5 at some space for a > stack and call printf in the same manner as the C example I cited? Not necessary to do anything with R5 (you can leave it blank); the only things a PDP-11 C routine needs are: - a good stack - the arguments, and return point, on the top of the stack csv will set up the frame pointer, making no assumptions about the old contents of R5 - see the source: http://ana-3.lcs.mit.edu/~jnc/tech/unix/lib/csv.s although it does save the old R5 contents, and restore them on exit. Noel

4 years

Re: [TUHS] Using printf from Assembly Language in V6, and db.

by jnc＠mercury.lcs.mit.edu

> From: Paul Riley > I want to use printf from an assembly language program, in V6. ... the > substitutional arguments for printf are pushed onto the stack in reverse > order, then the address of the string, and then printf is called. After > this, 6 is added to the stack pointer. This is all down to the standard C environment / calling sequence on the PDP-11 (at least, in V6 C; other compilers may do it differently). Calls to printf() are in no way special. Very briefly, there's a 'frame pointer' (R5) which points to the current stack frame; all arguments and automatics are relative to that. A pair of special routines, csv and cret (I couldn't find the source on TUHS, but it happens to be here: http://ana-3.lcs.mit.edu/~jnc/tech/unix/lib/csv.s if you want to see it), set up and tear down the frame on entry/exit to that routine. The SP (R6) points to a blank location on the top (i.e. lower address; PDP-11 stacks grow down) of the stack. To call a subroutine, the arguments are pushed, the routine is called (which pushes the return PC), and on return (which pops the return PC), the arguments are discarded by the caller. (I wrote a note, BITD, explaining how all this worked; I'll upload it to the CHWiki when I get a chance.) > I assume that the printf routine pops the address of the string off the > stack, but leaves the other values on the stack No, all C routines (including printf()) leave the stack more or less alone, except for CSV/CRET hackery, allocating space for automatic variables on routine entry (that would be at L1; try looking at the .s for a routine with automatic variables), and popping the return PC on exit. The exception to this is the stuff around calling _enother_ routine (sketched above). Another exception is alloca() (source here: http://ana-3.lcs.mit.edu/~jnc/tech/unix/lib/alloca.s again, couldn't find it in TUHS), which allocated a block of memory on the stack (automatically discarded when the routine which called alloca() returns). Note that since all automatic variables and incoming arguments are relative to the FP, alloca is _really_ simple; justs adjusts the SP, and it's done. > What troubles me is that the stack pointer is not decremented before the > first mov, in the example below. Is this some C convention? I would > assume that the first push in my example would overwrite the top of the > stack. That's right; that's because in the C runtime environment, the top location on the stack is a trash word (set up by csv). > I understand db only works on files like a.out or core dumps. If I > wanted to break the assembly language program to examine values, how can > I force a termination and core dump elegantly, so I can examine some > register values? Use 'cdb': https://minnie.tuhs.org//cgi-bin/utree.pl?file=V6/usr/man/man1/cdb.1 which can do interactive debugging. Noel

4 years

Using printf from Assembly Language in V6, and db.

by Paul Riley

Hi, I want to use printf from an assembly language program, in V6. It seems that the Unix Programmer's Manual doesn't show how to use it from assembly, so I wrote a short C program and captured the assembler output, for some clues. Listings below. In my example, the substitutional arguments for printf are pushed onto the stack in reverse order, then the address of the string, and then printf is called. After this, 6 is added to the stack pointer. I assume that the printf routine pops the address of the string off the stack, but leaves the other values on the stack, hence the need to add 2x3=6 to the stack after calling printf in my example. What troubles me is that the stack pointer is not decremented before the first mov, in the example below. Is this some C convention? I would assume that the first push in my example would overwrite the top of the stack. Perhaps I'm not used to PDP-11 stack conventions. I understand db only works on files like a.out or core dumps. If I wanted to break the assembly language program to examine values, how can I force a termination and core dump elegantly, so I can examine some register values? Paul *Paul Riley* Email: paul(a)rileyriot.com int a, b, c; int main(){ printf("printf: start\n"); a = 1; b = 2; c = 3; printf("A = %d, B = %d, C = %d", a, b, c); printf("printf: end\n"); } .comm _a,2 .comm _b,2 .comm _c,2 .globl _main .text _main: ~~main: jsr r5,csv jbr L1 L2:mov $L4,(sp) jsr pc,*$_printf mov $1,_a mov $2,_b mov $3,_c mov _c,(sp) mov _b,-(sp) mov _a,-(sp) mov $L5,-(sp) jsr pc,*$_printf add $6,sp mov $L6,(sp) jsr pc,*$_printf L3:jmp cret L1:jbr L2 .globl .data L4:.byte 160,162,151,156,164,146,72,40,163,164,141,162,164,12,0 L5:.byte 101,40,75,40,45,144,54,40,102,40,75,40,45,144,54,40,103,40,75,40,45,144,0 L6:.byte 160,162,151,156,164,146,72,40,145,156,144,12,0 #

4 years

demand paged 32V / Contacting Tom Raleigh

by Paul Ruizendaal

> The demand paging code for SysVR2 was written by Keith A. Kelleman and Steven J. Buroff, and in contemporary conference talks they were saying that they wanted to combine the best parts of demand-paged 32V and BSD. They may have some additional memories that could help with getting a better understanding of the final version of 32V. > > Does anybody have contact details for these two gentlemen? I’ve managed to contact Keith Kelleman and he had some interesting remarks. The paging code in SVR2 was all new code, with a focus the 3B dual processor. It does not derive at the code level from 32V and in fact he does not recall working with the 32V paging code. This kills the hope that the SVR2 code had clues about the 32V code. Keith did suggest that I tried to contact Tom Raleigh, who might have worked with the later 32V code base. Anybody with suggestions for locating him? === Besides functionality, the people that remember paged 32V all recall it being very fast. I wonder what made it fast. First to consider is “faster than what?”. Maybe Rob P. has a specific memory, but I would assume faster than 4BSD: if the comparison was with the "scatter loading, partial swapping” version of 32V people would have expected the better performance and not remember it as impressive 40 years later. Possibly the comparison is with 8th Edition which would have used the 4BSD paging code by then. If the comparison is with 4BSD, then the CoW feature in paging 32V would have been mostly matched by the vfork mechanism in 4BSD: it covers 80% of the use and it leaves the code paths simpler. If the comparison is with 8th edition, this may be the difference that people remember. The next possibility is that paging 32V had a better page-out algorithm. Joy/Babaoglu mention that the cost of the clock process is noticable. Maybe paged 32V used a VMS-like FIFO/second chance algorithm that did not need a separate kernel process/thread. Arguably this is not enough for a convincing speed difference. It is also possible that JFR found a more clever way to do LRU approximation. He remembers that his code used ‘strict LRU’, but not the algorithm. On Tenex - his conceptual reference - that was natural to do, because the MMU hardware maintains a table with 4 words of 36 bits for each frame with statistical data. With the VAX hardware it is a challenge. Considering his mathematical prowess it is maybe plausible that JFR found an efficient way. A slightly better page hit rate gives a significant speed improvement. All speculation of course: only finding the source will truly tell.

4 years

Re: [TUHS] "The programmer must have been carried away ...

by Paul Ruizendaal

> So there you have it. Just a line of B code that wasn't updated to C. > > Cheers, > aap I love posts like this, thank you! “Sherlock Holmes and the mysterious case of the excessive parameter list"

4 years

Code Review Request: 2.8BSD

by Warner Losh

Greetings, It has always bugged me that the bsd-family-tree file got 2.8BSD slightly wrong. It has the relationship V6 -> 1BSD -> 2BSD -> 2.79BSD -> 2.8BSD with V7 -> 32V -> 3BSD ... -> 4.1BSD -> 2.8BSD Now, as far as it goes, that's not terrible. But it's missing something. First, there was no V6 code in 1BSD or 2BSD through 2.79BSD. It was for V6 at first then for both V6 and V7, but w/o V7 code. There weren't even patches for V6 or new drivers on the early 1BSD and 2BSDs. However, starting with 2.8BSD, there's a V7 kernel. Or should I say a heavily patched V7 kernel with a ton of #ifdefs for all the fixes and enhancements collected by Berkeley and a few minor build system tweaks. Also, the code from 4.1BSD that's in 2.8 is rather minimal from what I can tell with my analysis so far, except indirectly in some of the patches to the V7 kernel appear to also be in 4.1BSD. The biggest thing that's in 2.8BSD from 4.1BSD is the job control (confined to its own directory with big warnings that basically say you'll need to update the code and even then the system is unstable). 2.9BSD has much better 4.xBSD integration, but 2.8 was quite early days for rejoining the two lines. 4.1BSD didn't have many berkeley rewrites of userland code, and the 2.8 tape has only a few of them (eg ls). So although it's not as complete as one would hope, there was a decent amount of code from 4.1BSD flowing into 2.8BSD. Now, my request. I've created a code review for FreeBSD to fix this. https://reviews.freebsd.org/D30883 is the review. We use phabricator in the FreeBSD project. Anybody can view this, but if you don't want to create an account, please send me email with a comment about the change and/or the commit message. It just adds an arc from V7 to 2.8BSD. Thanks for any time and/or insight you might have here. I'm judging the above entirely on the archived code rather than any historical knowledge... Warner

4 years

Re: [TUHS] [EXT] "The programmer must have been carried away ...

by Angelo Papenhoff

On 23/06/21, silas poulson wrote: > I’m aware line 2238’s famous “You are not expected to understand > this.” Comment is due to odd PDP-11/45 behaviour. Actually there are two different takes on what it is exactly that you're not expected to understand. The "obvious" one in Lions' book, (i.e. saved stack being overwritten when swapping so you have to restore from the special swap-saved stack), but dmr had a different take on it, that it had to do with functions really not being happy if you switch the stack underneath them. You can find dummy variables in the interdata port that make sure the stack frames of some functions (newproc and swtch?) match. So not really a hardware thing but a consequence of the compiler. > Do you know if other sections of the C show remnants of B or the PDP? > Or is it just those spots? For the kernel I'm just aware of this one. printf was copied over a number of times (the c compiler also includes a version) but the kernel was never written in B, so i wouldn't expect any B-ness in there otherwise. aap

4 years

"The programmer must have been carried away ...

by Angelo Papenhoff

... when he declared all the parameters for this procedure" I'm sure some of you remember this quote expressing John Lions' puzzlement over the declaration of printf in the UNIX kernel: printf(fmt,x1,x2,x3,x4,x5,x6,x7,x8,x9,xa,xb,xc) Note that parameters x2 and following are never referenced by name in the function body, only by pointer arithmetic from &x1. The historical reason for this long list of parameters is probably not well known, so I want to explain it and hope that you will find it as enjoyable as I did when I came across it some time ago while studying leftover files of B. To call a function in B, there's a little dance you have to do: first push the function address onto the stack, remember the stack pointer, push all the arguments, then restore the stack pointer and do the actual call. In diagrams, this is what happens to the B stack: push func addr: +------------+ | | <- sp +------------+ | func addr | +------------+ mark (n2): +------------+ | | <- sp +------------+ | | <- old sp (saved on native stack) +------------+ | func addr | +------------+ push arguments: +------------+ | | <- sp +------------+ | arg n | +------------+ | ... | +------------+ | arg 0 | +------------+ | | <- old sp (saved on native stack) +------------+ | func addr | +------------+ call (n3): pop old sp from stack jump to func addr on stack set ret addr and old fp +------------+ | arg n | +------------+ | ... | +------------+ | arg 0 | +------------+ | ret addr | +------------+ | old fp | <- sp, fp +------------+ The callee then sets sp, so has to know how many args and automatics! +------------+ | | <- sp +------------+ | auto n | +------------+ | ... | +------------+ | auto 0 | +------------+ | arg n | +------------+ | ... | +------------+ | arg 0 | +------------+ | ret addr | +------------+ | old fp | <- fp +------------+ So because the arguments to a functions were grouped together with the automatics and not below the ret addr and saved fp, there has to be space on the stack lest they clash. This of course means that this printf in B would probably break if called with more arguments than it expects. So there you have it. Just a line of B code that wasn't updated to C. Cheers, aap

4 years

Arithmetic expansion in Unix shells

by Michael Siegel

Hello, I'm currently trying out the rc shell (using Byron Rakitzis' implementation for Unix). Compared to Bash, which I normally use, this shell has a rather small feature set (which isn't to say that that's necessarily a bad thing). Now, one of the features that Bash has and rc doesn't have is the ability to perform arithmetic expansion. That's not really a problem because you can just use `expr` instead. I wonder, though, when arithmetic expansion as a shell built-in became a thing, especially in POSIX sh. POSIX has included that feature since at least 2001, and probably quite some years earlier, given that Bash already had it in 1995 (going by the manual page of version 1.14.7, the oldest I could find). So, maybe someone here can help me find out when this was actually standardized. Thanks. -- Michael

4 years

Re: [TUHS] Arithmetic expansion in Unix shells

by Brian Walden

even tho it was there, in-shell integer arithmetic had a few issues before ksh86. pre-ksh86 these had problems -- A. decimal point in a number $ integer I $ I=2.2 would error on the assignment, but with ksh86 $I is truncated to 2 (yes "integer" is an builtin alias to typeset -i and ksh courses at the time instructed to use that over typset) B. negative numbers $ integer I $ I=-2 here pre-86 $I would be assigned a large value like 2147483646 also ksh was not stardard until SVR4 (very late 80s) so it was found in paths like /usr/add-on/bin/ksh or /usr/exptools/bin/ksh, or not even there at all, you could not reliably #! ksh scripts also with ksh86 the double paren ((...)) notation was exactly the same as "let ..." and were completely optional if the variable was predefined as an integer, so $ I=0 $ ((I=I+1)) and $ integer I $ I=0 $ I=I+1 are the same. All internal integers in ksh were C longs (at least 32-bits) where Bourne shell all vars are strings so you would need to do this -- $ I=`expr $I + 1` But also at that time expr(1) could NOT deal with negative numbers on input, they became strings. So $ expr -9 + 1 is an error with "non-numeric argument", and $ expr -11 '<' -1 returns 0, a false statement, which are hidden bugs with variables. expr(1) was also 32-bits, as was test (i.e [ ) which could deal with negative numbers just fine. for arbitrarily large numbers you needed use dc(1) or bc(1). but dc(1) also has a issue with inputing negative numbers as it uses an _ not a - to denote a negatve number on input, but does use the - on output. $ I=`echo _9 1 - p | dc` is how you would do ((I=-9 - 1)) in bourne with dc which is cumbersome if you have a variable with a neagtive number in it, and required a "tr - _" first. however $ I=`echo -9 - 1 | bc` worked just fine in bourne. -Brian Chet Ramey wrote: > On 6/21/21 5:57 AM, arnold at skeeve.com wrote: > > Arithmetic expansion dates back at least as far as ksh88. > > ksh had the `let' builtin from at least 1983. The ((...)) compound command > was there by ksh-86. > > > Bash likely picked it up from there. > > Sort of, see below. > > > The original was only integer math and Bash remains that way (IIRC, > > Chet can correct me if I'm wrong). ksh93 added floating point math. > > Yes, bash only has integer arithmetic, since it's all POSIX requires. > > > POSIX would have picked it up from ksh88. > > The $((...)) form of arithmetic expansion is something POSIX picked up > from ksh-88, eventually. The early drafts of the standard (through 1003.2 > d9, at least), used $[...], but they eventually adopted $((...)) because > ksh-88 had already implemented it, though it's not documented in Bolsky > and Korn. > > I put $[...] into bash first (it's still there, though deprecated), then > `let', then $((...)) after POSIX added it, and finally `((' for > compatibility. > > Chet

4 years

demand paged 32V / Contacting Kelleman and/or Buroff

by Paul Ruizendaal

I’m still researching John Reiser’s 32V with demand paging, copy-on-write and mmap. Unfortunately, JFR does not have the bits or a listing for this version of 32V. I’ve read the MSc theses of Leffler and Shannon with interest (https://www.tuhs.org/Archive/Documentation/Theses/) The thesis of Shannon has an interesting discussion of a demand paged version of his Harris/6 Unix (Chapter 5). It is based on the Tenex ideas, just as JFR mentioned for his version. The thesis of Leffler contains a gant chart that shows that the demand paged version was written in the first months of 1980 -- concurrently with or slightly after the 32V version. I’ve also (superficially) read the papers on Tenex memory management. The design is closely tied to PDP-10 MMU that BBN designed for Tenex. Some of its data structuring is recognisable in Shannon’s version. One defining aspect is that the design for both is for a virtual address space that is smaller than the physical address space; on a 1980 VAX it was the reverse. If 32V followed the same design ideas (a big if), it most likely limited processes to a capped address space (e.g. 2MB). It might also have contained an in-core flag/data vector with as many entries as there are pages frames in swap space. If true, these downsides may have been why it did not go on to become the root for SysVR1 or R2 paging. The demand paging code for SysVR2 was written by Keith A. Kelleman and Steven J. Buroff, and in contemporary conference talks they were saying that they wanted to combine the best parts of demand-paged 32V and BSD. They may have some additional memories that could help with getting a better understanding of the final version of 32V. Does anybody have contact details for these two gentlemen?

4 years

70th anniversary of (official) programming errors

by Steffen Nurpmeso

Not Unix in particular. At least in Germany it is already the 16th, and my BSD calendar notifies that "first programming error is encountered at the U. S. Census Bureau". As not being hard-to-the-core i may have missed it, but also in 1951, in March, the wonderful Grace Hopper "conceives the first compiler, called A-O and later released as Math-Matic. Hopper is also credited with coining the term 'bug' following an incident involving a moth and a Mark II. All (hm!) according to COMPUTERWORLD January 18th, 1999 (i was young!), with assistance of the Computer Museum of Boston. Like McCartney said in the legendary 1999 concert at the Cavern club, the first after his wonderful wife Linda died, "See, with this band, if we don't get it right ... we start again!". Thank you. --steffen | |Der Kragenbaer, The moon bear, |der holt sich munter he cheerfully and one by one |einen nach dem anderen runter wa.ks himself off |(By Robert Gernhardt)

4 years

Re: [TUHS] Disassemblers

by norman＠oclsc.org

Rob Pike: Although upon reflection, I think what I did was fix 'adb' and call it 'db'. Haven't had my coffee yet this morning. ==== I don't think so. I did quite a lot of work on adb during my time at the Labs. I remember clearly that it still used all the Bournegol macros when I started; I doubt Rob would have left that there. (It was Rob who translated the shell back to C, I believe.) I got into adb because it still used ptrace and everyone else seemed scared to touch the code to convert it to use /proc. So I fixed that, and fixed sdb too, and finally removed the ptrace call from the kernel. I remember celebrating by expunging ptrace from the UNIX Room copy of the V8 manual. ptrace happened to occupt two facing pages, which I glued together. I did a lot more hacking on adb after that, ranging from little stuff like making # a synonym for 0x in input (so that adb's output could be picked up from the screen and re-used as input, a principle established firmly and correctly by Rob!) to a major restructuring to isolate machine-dependent pieces like instruction decoding and word formats, so that it was simpler not only to make adb work on a new processor architecture but even to make a sort of cross-adb that could, say, correctly interpret a PDP-11 core image on a VAX. (This actually mattered; by the time I arrived Research had no PDP-11s running general-purpose UNIX, but did have LSI-11s acting as Datakit controllers and a standalone power-backed-up LSI-11 that decoded the time signal from WWVB.) I was never really happy about the restructuring; it did more or less what I wanted but it wasn't really graceful. And cross-adb needed a distinct binary for each target. I had thoughts of trying to make a meta-language to describe the target's data formats (simple except for floating point) and how to print its instructions (messier, but I remember being inspired by the clever table-driven code in an disassembler Ken wrote for, I think it was, the NS32000), so that one could load a table from a file at startup; never had the time or the courage to carry through on it. Norman Wilson Toronto ON

4 years

Re: [TUHS] Disassemblers

by jnc＠mercury.lcs.mit.edu

> From: Henry Bent > From what I can gather the only way to reasonably examine the > disassembly of a program in the early days of Unix was adb. Is this > true? Was there a way to easily produce a full disassembly? 'adb' is quite late. We had it on the PWB1 (V6 enhanced, basically) system at MIT, so its roots lie before V7. (Every time I run across people who think V7 is early, I go into 'get off my lawn' mode.) The first thing I know of that could disassemble PDP-11 code on Unix was 'db', which dates back to V1: https://minnie.tuhs.org//cgi-bin/utree.pl?file=V1/man/man1/db.1 It wasn't optimal for doing disassembly, because it was non-trivial to dump an entire object file as assembler source - but it could be done. Later (V5 era) there was something called 'cdb', which was 'db' with extensions to make it useful for debugging code whose source was in C: https://minnie.tuhs.org//cgi-bin/utree.pl?file=V4/man/man1/cdb.1 There were other non-Unix disassembler (such as DDT), also. Noel

4 years

[tuhs] New version of a paper on Unix evolution

by Nelson H. F. Beebe

A new journal issue published today carries this paper: Diomidis Spinellis and Paris Avgeriou Evolution of the Unix System Architecture: An Exploratory Case Study IEEE Transactions on Software Engineering 47(6) 1134--1163 June 2021 https://doi.org/10.1109/TSE.2019.2892149 A preprint is available here: https://www.researchgate.net/publication/332826685_Evolution_of_the_Unix_Sy… However, it is dated four years ago, and after removing its cover page, diffpdf shows numerous changes compared to today's publication. In the new version, a footnote on the first page says Manuscript received 19 May 2018; revised 18 Dec. 2018; accepted 28 Dec. 2018. Date of publication 2 May 2019; date of current version 14 June 2021. ------------------------------------------------------------------------------- - Nelson H. F. Beebe Tel: +1 801 581 5254 - - University of Utah FAX: +1 801 581 4148 - - Department of Mathematics, 110 LCB Internet e-mail: beebe(a)math.utah.edu - - 155 S 1400 E RM 233 beebe(a)acm.org beebe(a)computer.org - - Salt Lake City, UT 84112-0090, USA URL: http://www.math.utah.edu/~beebe/ - -------------------------------------------------------------------------------

4 years, 1 month

Re: [TUHS] 70th anniversary of (official) programming errors

by Jason Stevens

Sounds very "Deus ex machina" like. Although it's hard to staple a ghost to your notebook. -----Original Message----- From: Bakul Shah To: Rob Pike Cc: The Eunuchs Hysterical Society Sent: 6/16/21 12:13 PM Subject: Re: [TUHS] 70th anniversary of (official) programming errors https://spectrum.ieee.org/the-institute/ieee-history/did-you-know-edison -coined-the-term-bug <https://spectrum.ieee.org/the-institute/ieee-history/did-you-know-ediso n-coined-the-term-bug> Like Edison, she (Grace Hopper) was recalling the word’s older origins in the Welsh bwg, the Scottish bogill or bogle, the German bögge, and the Middle English bugge: the hobgoblins of pre-modern life, resurrected in the 19th century as, to paraphrase philosopher Gilbert Ryle, ghosts in the machine. Electrical circuits can have "bad connections" so I do wonder if Edison coined this word based on "ghost like" faults that magically appear and disappear! -- Bakul On Jun 15, 2021, at 8:48 PM, Rob Pike <robpike(a)gmail.com> wrote: There are citations from Edison in the 19th century using the word, and a quote somewhere by Maurice Wilkes about the stairwell moment when he realized much of the rest of his life would be spent finding programming errors. That moth was not the first bug, nor the first "bug", it was the first recorded "actual bug". -rob On Wed, Jun 16, 2021 at 9:46 AM Dan Cross < crossd(a)gmail.com <mailto:crossd@gmail.com> > wrote: On Tue, Jun 15, 2021 at 6:55 PM John Cowan < cowan(a)ccil.org <mailto:cowan@ccil.org> > wrote: On Tue, Jun 15, 2021 at 6:25 PM Steffen Nurpmeso < steffen(a)sdaoden.eu <mailto:steffen@sdaoden.eu> > wrote: As not being hard-to-the-core i may have missed it, but also in 1951, in March, the wonderful Grace Hopper "conceives the first compiler, called A-O and later released as Math-Matic. Hopper is also credited with coining the term 'bug' following an incident involving a moth and a Mark II. Yes, but wrongly. The label next to the moth is "First actual case of bug being found", and the word "actual" shows that the slang term already existed then. Brief unexplained faults on telephony (and before that telegraphy) lines were "bugs on the line" back in the 19C. Vibroplex telegraph keys, first sold in 1905, had a picture of a beetle on the top of the key, and were notorious for creating bugs when inexperienced operators used them. (Vibroplex is still in business, still selling its continuous-operation telegraph keys, which ditt as long as you hold the paddle to the right.) Indeed, the Vibroplex key is called a "bug". I suspect this has something to do with its appearance more than anything else, though (it kinda sorta looks like, er, a bug). - Dan C.

4 years, 1 month

Help Contacting Unix Legal People

by Paul Ruizendaal

I understand the preference for a bottom-up entry, with somebody already sympathetic. If there is no such entry point, top-down may work at Microfocus. I guess the ask is for a statement for SysV similar to the Nokia statement for 8th-10th Edition: https://media-bell-labs-com.s3.amazonaws.com/pages/20170327_1602/statement%… According to Companies’ House, the general counsel is Jane Smithard: https://find-and-update.company-information.service.gov.uk/company/01504593… She appears to be 67, to have a long tenure with Microfocus and maybe is just the right person: "Jane has more than 25 years’ experience as a lawyer in the IT industry and software sector. She has worked with Micro Focus for over 20 years providing a wide range of commercial and corporate legal services, from leading the efforts through the 2005 IPO to driving the legal aspects of the group’s mergers, acquisitions and divestitures strategy including the acquisition of HPE Software and divestiture of SUSE. Jane leads a team of approximately 60 lawyers and other professionals worldwide, the majority of whom are focused directly on supporting the Company’s commercial teams and business.” https://www.microfocus.com/en-us/about/leadership-about Her e-mail appears to be jane (dot) smithard (at) microfocus (dot) com But I guess that Dan Doernberg already knows all that. His book project sounds intriguing, by the way. Paul

4 years, 1 month

Re: [TUHS] Help Contacting Unix Legal People

by Jason Stevens

I tried sending a letter a while back asking how much is a commercial SYSV license anyways, never got a reply. I called their legal and they didn't know what a Unix was. I guess shockingly all the public facing micro focus is all on cobol -----Original Message----- From: Warren Toomey To: tuhs(a)tuhs.org Sent: 6/10/21 8:32 AM Subject: [TUHS] Help Contacting Unix Legal People All, we need help contacting some people so that Dan Doernberg can make progress on a new Unix book that he's working on. I've attached his request to the TUHS list below. If you can help out in any way, please contact Dan directly. Cheers, Warren From: Peer-to-Peer Communications LLC <dan(a)peerllc.com> Hello all, I’m the publisher of Lions' Commentary on UNIX (still going strong after 25 years!) and I have an “Ancient UNIX” book project in mind that I need some community help with. To avoid running into any “who has copyright rights to UNIX” legal problems, we’re trying to reach out in advance to any companies/organizations that may have such rights (Micro Focus, Xinuos, Nokia, are there others?) in advance. To that end, I’m trying to find staffers there who are: 1. sympathetic to sharing information about “ancient UNIX” with the operating system/UNIX communities 2. somewhat familiar with the past legal issues and controversies over UNIX ownership (perhaps someone in the legal department) If you know any such person(s) at Micro Focus, Xinuos, Nokia, and/or other relevant organizations that has either quality (or ideally a unicorn with both!), please pass on their name and email address to me (even better, add any context about why they might be helpful to me, if it’s OK to say that you referred me to them, etc.]. Thanks much, all referrals greatly appreciated! Dan Doernberg dan(a)peerllc.com

4 years, 1 month

System IV

by Warner Losh

So I've seen a number of places that talk about Unix TS 3.0 -> 4.0 -> 5.0 progression and how System III was released and System V was released and System IV was internal only. What I've not seen is the "why" part of this. Why was it internal only? Warner

4 years, 1 month

Jump to page:

2025

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

2001

2000

1999

1998

1997

1996

1995

1994

1993

1992

1991

1990

TUHS