Re: PDP-11 Xenix

Dave, <I don't think John has it at ftp.dbit.com. And I doubt that XENIX is <anywhere on the net. I don't even know if there was a PDP-11 XENIX. (It <was originally MS, afterall. They "sold" it to SCO way back, before SCO <collected everything else.) Your right, drain beth, err brain death. Sometimes all those *nixs are the same to me. Especially after configuring three vaxen for VMS and installing it. I know heresy but, Netbsd has proven uninstallable here on all four systems. <DEC Pro350/380, which is, essentially, a PDP-11. There was also a VENIX <for "real" PDP-11s. Well venix on the pro350 runs far better than POS! In fact it's the only *nix running here as even slackware has had problems (bad CD!). That however is news! Is there a version of venix for "real" PDP-11s? on the net? Allison Received: (from major@localhost) by minnie.cs.adfa.oz.au (8.8.5/8.8.5) id OAA16515 for pups-liszt; Fri, 10 Oct 1997 14:46:48 +1000 (EST) X-Authentication-Warning: minnie.cs.adfa.oz.au: major set sender to owner-pups(a)minnie.cs.adfa.oz.au using -f Received: from freebie.lemis.com (gregl1.lnk.telstra.net [139.130.136.133]) by minnie.cs.adfa.oz.au (8.8.5/8.8.5) with ESMTP id OAA16510 for &lt;pups(a)minnie.cs.adfa.oz.au&gt;au>; Fri, 10 Oct 1997 14:46:43 +1000 (EST) Received: (from grog@localhost) by freebie.lemis.com (8.8.7/8.8.5) id OAA22633; Fri, 10 Oct 1997 14:16:33 +0930 (CST) Message-ID: &lt;19971010141633.30732(a)lemis.com&gt; Date: Fri, 10 Oct 1997 14:16:33 +0930 From: Greg Lehey &lt;grog(a)lemis.com&gt; To: Allison J Parent &lt;allisonp(a)world.std.com&gt; Cc: djenner(a)halcyon.com, pups(a)minnie.cs.adfa.oz.au Subject: Re: PDP-11 Xenix References: &lt;199710100412.AA13660(a)world.std.com&gt; Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 0.84e In-Reply-To: &lt;199710100412.AA13660(a)world.std.com&gt;om>; from Allison J Parent on Fri, Oct 10, 1997 at 12:12:45AM -0400 Organisation: LEMIS, PO Box 460, Echunga SA 5153, Australia Phone: +61-8-8388-8250 Fax: +61-8-8388-8250 Mobile: +61-41-739-7062 WWW-Home-Page: http://www.lemis.com/~grog Fight-Spam-Now: http://www.cauce.org Sender: owner-pups(a)minnie.cs.adfa.oz.au Precedence: bulk On Fri, Oct 10, 1997 at 12:12:45AM -0400, Allison J Parent wrote: I thought SCO developed XENIX right from the word go, only in those days they belonged to Microsoft. Interesting. What was the problem? Greg Received: (from major@localhost) by minnie.cs.adfa.oz.au (8.8.5/8.8.5) id BAA17679 for pups-liszt; Sat, 11 Oct 1997 01:02:58 +1000 (EST) X-Authentication-Warning: minnie.cs.adfa.oz.au: major set sender to owner-pups(a)minnie.cs.adfa.oz.au using -f Received: from mail1w-int.prodigy.net (pimout1-ext.prodigy.net [198.83.18.53]) by minnie.cs.adfa.oz.au (8.8.5/8.8.5) with ESMTP id BAA17674 for &lt;pups(a)minnie.cs.adfa.oz.au&gt;au>; Sat, 11 Oct 1997 01:02:51 +1000 (EST) Received: from seeker.prodigy.com (seeker.prodigy.com [199.4.137.72]) by pimout1-int.prodigy.net (8.8.5/8.8.5) with SMTP id KAA81722 for &lt;pups(a)minnie.cs.adfa.oz.au&gt;au>; Fri, 10 Oct 1997 10:57:23 -0400 From: "Frank Wortner" &lt;fwortner(a)prodigy.net&gt; To: "PDP-11 Unix Preservation Society" &lt;pups(a)minnie.cs.adfa.oz.au&gt; Subject: Re: PDP-11 Xenix (LONG) Date: Fri, 10 Oct 1997 10:57:18 -0400 Message-ID: &lt;01bcd58c$ce268560$488904c7(a)seeker.prodigy.com&gt; MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 4.71.1712.3 X-MimeOLE: Produced By Microsoft MimeOLE V4.71.1712.3 Sender: owner-pups(a)minnie.cs.adfa.oz.au Precedence: bulk Since I'm the one that started this --- albeit indirectly --- let me try to explain. Way back when --- about 1981 or 82 --- I worked for a small (now defunct) software company. We owned 2 PDP-11/23s. Initially, we ran a distribution of the Sixth Edition on them. That came from a company in New York --- that's where I am geographically, BTW --- called Yourdon. The system was called UV6. After a while, we decided to upgrade to V7. At the time, we had begun a relationship with another (now defunct) firm called Lifeboat Associates (also in New York, later in Tarrytown, NY). They distributed microcomputer software, principally CP/M-based. They were a Microsoft distributor. Microsoft had just started Unix development at the time. Lifeboat sold us a V7 system: Microsoft PDP-11 Xenix. I know it was Microsoft because the tape lables said so, and I remember that the line printer printed release notes contained a banner page that indicated that they came from Microsoft's DEC 20(!) (cheerfully named "Microsoft Heating Plant"). PD.-11 Xenix was essentially V7, but it had a few added features. Processor support included all models of PDP-11 with MMUs: 23s, 34s, 40s, 45s, 55s, 60s, and 70s. It had split I&D space emulation --- borrowed, I believe from 2.something BSD. That emulation required a grand total of three(!) link passes, but the compiler driver was modified to do this automatically if you specified the "-j" option. Instead of source, the kernel was delivered mostly as .o files and .a libraries, so you could reconfigure the OS without source. The reconfigure programs just spat out some assembly language and C "glue" that you compiled and linked with the .o and .a files. In fact, this was pretty much automated. The system also had a rather extensive /etc./shutdown shell script which calmly and thoroughly brought the system to a quiescent state and could optionally reboot or halt it. Although the OS was pretty big --- I find it amazing that I thought of it as "big" ;-) --- you could, with some effort build a boot floppy on a RX02 diskette. That could run exactly 1 (one) process --- the RX02 system had *no* swap space. I remember system recovery sessions in which I constantly had to boot the floppy, see the shell prompt, and then "exec fsck" and watch as fsck finished its run, and init respawned the shell! Anyhow, I know I *used to have* the release notes and I *might* have had the tape, but both, sadly, are probably lost. I was wondering if anyone else might have seen or, even better, still has a tape of this rare version of V7. Perhaps there's an archive at Microsoft or SCO that harbors a tape. Most software firms do have some sort of policy about placing products in escrow with a third party. Maybe this still exists. If not, that's OK. If SCO is kind enough to allow source licensing to individuals for noncommercial use, then this largely becomes a moot issue. Full source V7 (or even better 2BSD) is probably a more "interesting" system from a hobbyist or preservationist point of view, particularly if you're like me and don't have or care to own actual PDP-11 hardware. I'm quite happy to run John Wilson's and Bob Supnick's wonderful emulator programs with whatever software I can obtain. They let me have the PDP-11 models I worked on (23, 34, 45) as well as those I'd like to have had (70) without the hassle and expense of maintaining the actual hardware. BTW, if John or Bob reads this list, l'd like to say "Thank you" to both of them. Also thanks to Warren for his work preserving the old Unix software. It's a great deal of fun to see old "friends" again, and I think it will be just as much fun to see software and "hardware" combinations that I didn't have access to in the "good old days." Thanks also to SCO for binary licenses for these "historic" systems; I hope that they will be able to license source code in the near future. Sorry for the long ramble and thanks for reading! Frank Received: (from major@localhost) by minnie.cs.adfa.oz.au (8.8.5/8.8.5) id DAA17931 for pups-liszt; Sat, 11 Oct 1997 03:15:43 +1000 (EST) X-Authentication-Warning: minnie.cs.adfa.oz.au: major set sender to owner-pups(a)minnie.cs.adfa.oz.au using -f Received: from moe.2bsd.com (0(a)MOE.2BSD.COM [206.139.202.200]) by minnie.cs.adfa.oz.au (8.8.5/8.8.5) with ESMTP id DAA17926 for &lt;pups(a)minnie.cs.adfa.oz.au&gt;au>; Sat, 11 Oct 1997 03:15:37 +1000 (EST) Received: (from sms@localhost) by moe.2bsd.com (8.8.5/8.8.5) id JAA20665; Fri, 10 Oct 1997 09:55:45 -0700 (PDT) Date: Fri, 10 Oct 1997 09:55:45 -0700 (PDT) From: "Steven M. Schultz" &lt;sms(a)moe.2bsd.com&gt; Message-Id: &lt;199710101655.JAA20665(a)moe.2bsd.com&gt; To: fwortner(a)prodigy.net, pups(a)minnie.cs.adfa.oz.au Subject: Re: PDP-11 Xenix (LONG) Sender: owner-pups(a)minnie.cs.adfa.oz.au Precedence: bulk Howdy - And I hate to see a fellow talk to himself without interruption ;-) I remember (not terribly fondly) running V7 on an 11/23. We hacked in an overlay scheme to the kernel (but not user programs). Just enough resources to run 1 user and a couple processes - do an "ls" and the shell got swapped out, when 'ls' finished the shell would get swapped back in. Wheee! ;) Not having used Xenix I'd never heard the term "split I&D space emulation". What we hacked in to V7 and BSD later implemented was an even older concept: overlays. 2.9 was the first version I know of that had 'overlay' support. The overlays were memory resident and switching between them was done by flipping MMU registers. It is (present tense since 2.11BSD uses the same method today) done with a single link phase (no "-j" option or multiple link edits). In 2.9 there was a limit of 7 overlay segments plus the base segment. Later on (the 1985 update to 2.9) the limit was increased to 15 overlays which has proven to be adequate since then. For the kernel the overlays could only be 8kb (1 page register) but user mode programs could have larger (but still multiple of 8kb) overlays. In 2.9 there was a separate libc.a that you did need to link with because the callframe had an extra word (the overlay number) and 'csv, cret' had a couple extra instructions to switch overlays. Later (2.10 and up) the callframe was changed to always have the extra word This made life easier (at the expense of an extra 3microseconds per function call) by not having to maintain/build two versions of all the libraries. A multiphase link IS currently used to build the 2.11 networking though. The networking code (4.3BSD's TCP/IP stack) runs in supervisor mode. The kernel, at boot time, loads /netnix into supervisor space. The /netnix image is built in a similar manner to what was mentioned for Xenix's emulated I&D space - first build the unix image (with undefined references to the networking code), then build the netnix image (with undefined references to the kernel code), then cross reference the two images for undefineds and create .s stub files to satisfy the undefineds. Assemble the two .s files and then link unix with d.netnix.o and netnix with d.unix.o and voila a kernel and an image it can load into supervisor space. Even V7 had trouble fitting on a non split I/D machine. The problem is that the kernel has to map the I/O page which removes an extra MMU page from being used for data. Then the 'u' area needs a page (for the kernel stack and per process context). And you need a page to perform copyin/copyout with (and to map the buffer cache if that has been moved external to the kernel) - that leaves only 40kb for everything else (and on a nonsplit I/D machine with overlays you'd need two or three pages for the base segment and an overlay, that leaves just 2 pages or 16kb for all the data). An 11/73 takes up less space than some PC tower cases and uses about the same amount of electricity. I can't speak for John's emulator (only runs on top of DOS and my place is a MS-free zone ;)) but I have booted up 2.11BSD under Bob's. Only went to the single user state and ran a couple simple commands. Seems to work ok that far, but 'vi' doesn't run right - I suspect it's something to do with overlaid programs flipping MMU registers about but haven't had the time to look into it further (besides which I've a 11/73 and a 11/93 to use). A Q-bus system such as an 11/83 combines the best of both worlds - it's got the address space and the speed (cpuwise) of a 70 but the convenience of no UNIBUS map (like the 45). Maintenance thus far over the last 6 years has consisted of replacing an M8192 when the cache developed a parity error. Well, I suppose I should get back to work before the boss wanders by and sees me having fun instead of getting his work done ;-) Steven Schultz