TUHS

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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, 8 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, 8 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, 8 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, 8 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, 8 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, 8 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, 8 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, 8 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, 8 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, 8 months

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