TUHS

tuhs@tuhs.org

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6506 discussions

Re: [TUHS] 2.9bsd with networking on 18-bit possible?

by jnc＠mercury.lcs.mit.edu

> From: Paul Ruizendaal > project to make V6 run with the Gurwitz TCP stack on a TI990 clone > (which is pretty similar to a PDP11). Neat! > the code size is about 25KB for both a minimal V6 kernel and the TCP > stack, the rest is data. That's impressively small; the MIT V6+ with 'demux only in the kernel' was 40KB for the combined code (although I can't easily get separate figures for the networking part and the rest). > The Gurwitz code also has an Ethernet driver (note ARP was not invented > yet) How did it get Ethernet addresses? Noel

6 years, 5 months

2.9bsd with networking on 18-bit possible?

by Paul Ruizendaal

> I'm sure it's been attempted before, but would anyone be up to the > challenge of trying to get that going with networking on an > 18-bit-address-space pdp11? By coincidence I’m in the middle of a project to make V6 run with the Gurwitz TCP stack on a TI990 clone (which is pretty similar to a PDP11). It runs without separate I/D as two processes in about 100KB. The Gurwitz TCP stack was the reference implementation for the VAX that BBN did in 1981. It is in the THUS archive: https://minnie.tuhs.org//cgi-bin/utree.pl?file=BBN-Vax-TCP As documented in IEN168, the actual TCP processing happens in a separate kernel process, much like process 0 (swapper) in Unix itself. It turns out that the network process shares no data (other than the u struct) with the kernel proper and can be run in a separate address space. Just a few ’thunks’ are needed: open/read/write/close from the kernel to the TCP stack and sleep/wakeup in the other direction. A V6 Unix kernel runs in 48KB with buffers, the TCP stack with buffers needs about the same; both must remain resident - i.e. it ties up about 100KB of the 256KB core on a 18-bit machine. I suppose when using separate I/D it can run without thunks: the code size is about 25KB for both a minimal V6 kernel and the TCP stack, the rest is data. In my setup, network connectivity is via a SLIP interface. The Gurwitz code also has an Ethernet driver (note ARP was not invented yet), but I’m not using that. I’m happy to report that this 1981 tcp/ip code can still talk to current OSX and Linux machines. Just yesterday I got the setup working and I can run minimalist telnet connections etc. Alas it is not quite stable yet, it tends to crash after 5-10 minutes of use. The BBN reference implementation includes FTP and Telnet servers and clients which I think will still interoperate with current versions. As a final remark note that this BBN code uses an API that is almost unchanged from the API as used on NCP Unix. As compared to sockets this means that a listening connection is not a rendez-vous, but blocks until a connection is made (and then becomes an active connection, i.e. stops listening), and that there is no “select” type functionality.

6 years, 5 months

Re: [TUHS] 2.9bsd with networking on 18-bit possible?

by jnc＠mercury.lcs.mit.edu

> From: Clem Cole > I could be mis remembering No... :-) > IIRC the original PTY driver goes back to the Rand and/or UofI for the > NCP. Yup. I found a pty.c in the NCP system, it's clearly the ancestor (comments match): https://minnie.tuhs.org//cgi-bin/utree.pl?file=SRI-NOSC/dmr/pty.c > I suspect BBN got it from the Bruce Borden's Rand distribution tape Or possibly indirectly; my copy of the NCP came from NOSC via SRI. In addition to the one above, there are also these: https://minnie.tuhs.org//cgi-bin/utree.pl?file=SRI-NOSC/dmr/misc/pty.c.ill https://minnie.tuhs.org//cgi-bin/utree.pl?file=SRI-NOSC/dmr/misc/pty.c.x Here: https://minnie.tuhs.org//cgi-bin/utree.pl?file=BBN-V6/dmr/pty.c is the BBN version, you can compare the them all. The MIT one is derived from the BBN one. > Named Piped were definiately a Rand-ism (they were originally called 'Rand Pipes') Well, _RAND_ called them 'ports': https://minnie.tuhs.org//cgi-bin/utree.pl?file=BBN-V6/doc/ipc/ports > But there were issues and somethings were not 100% until the UofI NCP; > which was the first really complete NCP for UNIX. Somewhere I found a document about the UofI code, I think they wrote it from scratch? Sorry, too lazy to look at it. See here: https://minnie.tuhs.org//cgi-bin/utree.pl?file=SRI-NOSC for links. Noel

6 years, 5 months

Re: [TUHS] 2.9bsd with networking on 18-bit possible?

by jnc＠mercury.lcs.mit.edu

PS: > IIRC, outbound packets are copied into kernel buffers IDRC; according to the documentation, outbound packets are DMA'd directly from user memory. I have yet to read the code to verify this. > we must have added PTY's of some sort There is indeed a PTY driver; it has comments from BBN'ers who edited it, so perhaps we got it from BBN. > I don't remember which one SMTP used. The 'simple' TCP. > The whole thing worked _really_ well. Alas, I don't think anyone else > picked up on it. So I found a long list of people we sent tapes to. Oh well.... > The kernel code is not that large, it should even run on a /40, without > overlays (although the number of disk buffers would probably get hit). Well, maybe... Here is the output of 'size' on the last Unix image for that machine: 40560+3098+44594 It was a /45, so split I/D (no overlays, though). How much could be trimmed out of that, I'm not sure. Noel

6 years, 5 months

2.9bsd with networking on 18-bit possible?

by Jacob Ritorto

Hi, I have an 11/45 I'm hoping will be running soon. I'd like to run 2.9BSD on it because it's the most highly functional system I know of that has "official hopes" to fit on such a restrictive machine. I've heard that it's really unlikely / tough to get a kernel built that'll run tcp (I care mostly about ftp and telnet) on such a small-memory-footprint machine. Is this true? Would anyone be willing to do a quick mentoring / working session with me to get me up to speed with the constraints I'm facing here and possibly give me a jump on making adjustments to build such a kernel if possible? thx jake P.S. There's kind of an implied challenge in the 2.11bsd setup docs, mentioning that "2.11BSD would probably only require a moderate amount of squeezing to fit on machines with less memory, but it would also be very unhappy about the prospect." I'm sure it's been attempted before, but would anyone be up to the challenge of trying to get that going with networking on an 18-bit-address-space pdp11?

6 years, 5 months

Re: [TUHS] 2.9bsd with networking on 18-bit possible?

by jnc＠mercury.lcs.mit.edu

> From: Clem Cole <clemc(a)ccc.com> > This is why I suggested that if you really want telnet and ftp to the > PDP-11, you might be better off moving the networking stack out of the > kernel Really, the answer is that I need to get off my @ss and put the MIT V6+ system up (I have all the files, just need to get a round tuit). It has TCP/IP, but is it not all crammed into the kernel. And unlike the early BBN V6, it doesn't do TCP as a single process to which all the other client/server processes talk via IPC. Instead, the only thing in the kernel is inbound demuxing, and minimal outbound processing. (IIRC, outbound packets are copied into kernel buffers; an earlier version of the networking interface driver actually did do inbound and outbound DMA directly from buffers in the user's process, but only one process could use the network interface at a time.) The TCP code was a library that was built into the user process which did the server/client applications. (The servers which supported login, like FTP, needed to run as root, like the ordinary login, setuid'ing to the entered user-id.) I don't remember if we supported server Telnet, but I think we did. So we must have added PTY's of some sort, I'll have to check. Since the TCP was in the user process, we actually had a couple of different ones, depending on the application. Dave Clark had done a quick-n-dirty TCP on the Alto (in BCPL) which was only good for things like user Telnet, not for applications that sent a lot of data. We ported that one for the first TCP; we later did a 'high-speed bulk data' TCP, used for FTP, etc. I don't remember which one SMTP used. The whole thing worked _really_ well. Alas, I don't think anyone else picked up on it. The kernel code is not that large, it should even run on a /40, without overlays (although the number of disk buffers would probably get hit). And since the TCP is in user processes, it could all get swapped out, so it would run OK on machines without that much physical memory. The issue is going to be that it will need a new network interface driver, since I think the only driver ever done for it was for Pronet. And now we get back to the 'what interfaces are available' question. Doing a DEC driver would allow use of DEQNA's and DELQA's on QBUS machines, which would be optimal, since they are common. And people could bring up Unix with TCP/IP on -11/23's. But we'd have to add ARP (which I would do as a process, with only the IP->Ether address mapping table stored in the kernel). I wrote a really nice ARP for the C Gateway that could easily be used for that. Noel

6 years, 5 months

Re: [TUHS] 2.9bsd with networking on 18-bit possible?

by jnc＠mercury.lcs.mit.edu

> From: Warner Losh > I kinda doubt it has good NCP support: it was released in November of > 1983. Wow, that far back? I'd assumed it was later (considerably later). Looking at the 2.9 networking stuff: https://minnie.tuhs.org//cgi-bin/utree.pl?file=2.9BSD/usr/net/sys/net it does indeed have _no_ NCP support. > I'd get it running in simh, then move to real hardware. Absolutely; running in an emulator is, I have found, a key step on getting an old OS running. I've found Ersatz-11 to be really good for PDP-11 emulation. > It's going to take a lot of elbow grease to make that work, I think. Indeed; part of the problem, if the goal is going to be 'run it on real hardware' is 'what network interface to use'. All the ARPANET interfaces are out. There are drivers there for Proteon, Ungermann-Bass, Xerox 3MB Ethernet, etc interfaces, but i) where you gonna find one, and ii) you'll need a router to connect up to most other things. There's a driver for the Interlan Ethernet interface, but AFAIK, those are non-existent. (If anyone has one they're willing to part with, please let me know!) DEC Ethernet interfaces are available, but i) only the QBUS ones are common, DEUNAs and DELUAs are almost impossible to find, that I've even seen, and ii) it would need a driver. > Ultrix-11 is of similar vintage, and similar functionality and does boot > on the 18-bit 11's. Yes, definitely worth looking at; I know it had TCP/IP (we had it on our -11/73 at Proteon), but I don't know which interfaces it supported; probably just the DEC ones (which, given the above, is not necessarily a Bad Thing). Noel

6 years, 5 months

Re: [TUHS] 2.9bsd with networking on 18-bit possible?

by jnc＠mercury.lcs.mit.edu

> From: Grant Taylor > What protocols did 2.9BSD support? Did it have NCP? NCP was turned off on 1 January, 1983. What do you think?a > Would it be any easier to use an external NCP to TCP/IP gateway? Such as? Noel

6 years, 5 months

Happy birthday, Grace Hopper and J.F.Ossana!

by Dave Horsfall

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

6 years, 5 months

Grace Hopper

by Dave Horsfall

We gained Rear Admiral Grace Hopper on this day in 1906; known as "Amazing Grace", she was a remarkable woman, both in computers and the Navy. She coined the term "debugging" when she extracted a moth from a set of relay contacts from a computer (the Harvard Mk I) and wrote "computer debugged" in the log, taping the deceased Lepidoptera in there as well. She was convinced that computers could be programmed in an English-like language and developed Flow-Matic, which in turn became, err, COBOL... She was posthumously awarded the Presidential Medal of Freedom in 2016 by Barack Obama. -- Dave

6 years, 5 months

Re: [TUHS] C comments

by Doug McIlroy

Very little in language design is so contentious as comment conventions. C borrowed the PL/I convention, which had the virtue of being useful for both in-line and interlinear comments, and did not necessitate marking every line of a long comment. Nobody in the Unix lab had had much experience with the convention, despite having worked on Multics for which PL/I was the implementation language. And how did PL/I get the convention? It was proposed by Paul Rogoway at the first NPL (as it was then called) design-committee meeting that I attended. Apparently the topic had been debated for some while before and people were tired of the subject. Paul was more firmly committed to his new idea than others were to old options, so it carried more or less by default. Besides, there was a much more interesting topic on the agenda. Between the previous meeting and that one, George Radin had revamped the entire NPL proposal from mainly Fortran-like syntax to Algol-like. That was heady enough stuff to divert people's attention from comments. As for inexperiece. The comment conventions of previous languages had not fostered the practice of commenting out code. So that idea, which is the main impetus for nesting comments, was not in anybody's mind at the time. Had it been, nesting might well have carried the day. It probably could have been changed before 1980, but thereafter there were too many C compilers. Then standards introduced even more conservatism. Perhaps Ken can remember whether the notion was ever seriously considered. Doug

6 years, 5 months

DEC compilers (was Happy birthday, John Backus!)

by Paul Winalski

Another DEC compiler that I forgot was the original C compiler for Tru64 Unix on the Alpha. This was done at the DECwest facility in Seattle (which originally had been set up by Dave Cutler). It was a very strict implementation of the ANSI C89 standard--it had no extensions such as K&R support. One customer called it the "Rush Limbaugh of C compilers" because it was extremely conservative and you couldn't argue with it. -Paul W.

6 years, 5 months

SDF's celebration of 50 years of UNIX

by Edouard KLEIN

Hi all, I haven't seen this on the list yet (apologies if I missed it): https://unix50.org/ You can get a shell in various historical version of UNIX. Enjoy !

6 years, 5 months

Re: [TUHS] c's comment

by Richard Tobin

> Why can't c language comments be nested? For comments that really are comments, what would be the point? For comments that are really removal of code - commenting out - there is a better mechanism, #if (or #ifdef), which does nest. -- Richard -- The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336.

6 years, 5 months

c's comment

by Caipenghui

Why can't c language comments be nested? What is the historical reason for language design?Feeling awkward. Caipenghui

6 years, 5 months

Re: [TUHS] Stories

by Doug McIlroy

> So how was it that so many smart - and somewhat like minded it seems > people end up there? [At Bell Labs] 1. Bell Labs had a great reputation, though it was not at first known for computing. 2. Research recruiters were researchers themselves, not HR people. 3. Recruiting was for quality hires, not for particular jobs; complementary talent was valued. 4. Whom a candidate met on site was determined after s/he gave a seminar; this promoted good matchups. 5. Researchers decided for themselves what to work on--either self- generated or an interesting problem from elsewhere in the company. 6. If you needed to know something in most any field, you could usually find a willing expert to get you on track to an answer. 7. Annual merit review was collegial. No one lost out because of unlucky draw of a supervisor. 8. Collegiality in fact beat that of any faculty I know. Office doors were always open; new arrivals needed only to do good work, not to chase tenure. This culture grew from the grand original idea of the Labs: R&D for the whole of AT&T funded by the whole of AT&T, with a long time horizon. I joined thinking the Labs was good seasoning for academia. The culture held me for 39 years. The premise was viable in the days of regulated monopoly. It has been greatly watered down since. Doug

6 years, 5 months

stories

by Larry McVoy

Ken's story got me thinking about stuff I would still like to learn and his comment about "when I got to Bell Labs"... made me wonder how did Ken, Dennis, Brian, Joe and the rest of the crew make their way to Bell Labs? When I was just starting out, Sun was sort of the Bell Labs of the time (not that Sun was the same as Bell Labs but it was sort of the center of the Unix universe in my mind). So I wanted to go there and had to work at it a bit but I got there. Was Bell Labs in the 60's like that? If you were a geek was that the place to go? I was born in '62 so I don't have any memory of how well known the Labs were back then. So how was it that so many smart - and somewhat like minded it seems - people end up there? --lm

6 years, 5 months

Re: [TUHS] DEC compilers (was Happy birthday, John Backus!)

by Norman Wilson

Lars Brinkhoff: There was also NIL, for VMS. Was it ever finished? ==== If so, is there a pointer to it? Norman Wilson Toronto On

6 years, 5 months

Re: [TUHS] Happy birthday, John Backus!

by jnc＠mercury.lcs.mit.edu

> From: Toby Thain > He made amends by being early to recognise that problem, and propose > solutions, in his 1977 ACM Turing Award lecture Actually, I'd consider a far bigger amend to be his work on Algol 60 (he was one of the main contributors), which Hoare so memorably described as "a language so far ahead of its time that it was not only an improvement on its predecessors but also on nearly all its successors". AFAICT, although Algol 60 itself is no longer used, basically _every_ modern programming language (other than wierd, parallel ones, etc) is heavily descended from Algol 60 (e.g. C, via CPL). As for FORTRAN, it's worth recalling that it was originally for the IBM 704, which was their very _first_ commercial computer with core memory! And not a lot of it - early 704's came with a massive 4KW of main memory! So the compiler had to be squeezed into _very_ small space - and it reportedly did an excellent job of emitting efficient code (at a time when a lot of people thought that couldn't be done, and so were hostile to the concept of writing program in HLL). And the compiler had to be written entirely in assembler, to boot... Which brings up an interesting query - I wonder when/what the last compiler written in assembler was? I gather these days compilers for new machines are always bootstrapped as cross-compilers (an X compiler for the Y machine is written in X, run through the X compiler for the [existing] Z machine, and then run though itself, on the Z machine, to produce binary of itself for the Y machine). Noel

6 years, 5 months

Re: [TUHS] Tandem NSK implementation language (was: Happy birthday, John Backus!)

by Paul McJones

> On Dec 4, 2018, Greg 'groggy' Lehey <grog(a)lemis.com> wrote: > > The original Tandem OS (called Guardian at the time) was written in Tandem's TAL (Transaction Application Language, amongst other productions), a vague evolution of HP's SPL that looked more like Algol, starting in about 1974. That is also the earliest I know of an operating system being implemented entirely in a high level language. Most likely the earliest operating system written in a high-level language was the one for the Burroughs B5000 (early 1960s), written in a dialect of Algol 60. Others: Multics, written in PL/1 (starting in mid 1960s), the operating system for the Berkeley Computer Corporation’s BCC-500, written in BCC SPL (system programming language) (late 1960s), OS6 by Stoy and Strachey, written in BCPL (early 1970s), Xerox Alto OS, written in BCPL (about 1974).

6 years, 5 months

ARPAnet now 4 nodes

by Dave Horsfall

The ARPAnet reached four nodes on this day in 1969 (anyone know their names?); at least one "history" site reckoned the third node was connected in 1977 (and I'm still waiting for a reply to my correction). Well, I can believe that perhaps there were only three left by then... Hmmm... According to my notes, the nodes were UCSB, UCLA, SRI, and Utah. -- Dave

6 years, 5 months

In Memoriam: John Lions

by Dave Horsfall

We lost Dr. John Lions of this day in 1998; he was one of my Comp Sci lecturers (yes, I helped him write The Book, and yes, you'll find my name in the back). -- Dave

6 years, 5 months

Happy birthday, John Backus!

by Dave Horsfall

As every computer programmer should know, John Backus was emitted in 1924; he gave us the BNF syntax (he is the "B"), but he also gave us that FORTRAN obscenity... Yeah, it was a nice language at the time; the engineers loved it, but tthe computer scientists hated it (have you ever tried to debug a FORTRAN program that somebody else wrote?). Trivia: there is no way that FORTRAN can be described in any syntax; it is completely ad-hoc. -- Dave

6 years, 5 months

> there is no way that FORTRAN can be described in any syntax

by Doug McIlroy

I did just that. The National Bureau of Standards picked it up in NBS Handbook 131, "Using ANS FORTRAN" (1980). It is expressed in the same formalism that Burroughs used for Algol. Doug

6 years, 5 months

The (un)importance of roff

by Doug McIlroy

Thhis is a cross-posting from the groff mailing list, where it was speculated that without roff there might be no Unix. Old hands will be familiar with the story. > Without roff, Unix might well have disappeared. The patent department and the AT&T president's office are the only in-house examples I know where Unix was adopted because of *roff. The important adoptions, which led Berk Tague to found a separate Unix Support Group, were mainstream telephone applications and PWB, a Unix-based IDE. The first telephone application happened in the field. An engineer in Charlotte, NC, heard of this cheap easily programmed system and proposed to use it to automate the scheduling and dispatch of maintenance on the floor of a wire center. Ken visited to help get them started. The first Bell Labs telephone application was automating the analysis of central-office trouble reports. These had been voluminous stacks of punched cards that reported every anomaly detected in huge electromechanical switches. The Unix application captured the data on line and identfied systematic failures in real time. The patent adoption was a direct result of Joe Ossanna's salesmaship. Other early adopters were self-motivated, but the generous support lent by Ken, Joe, and others was certainly a tipping force that helped turn isolated events into a self-sustaining movement. Doug

6 years, 5 months

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TUHS