> From: Dan Cross
> I believe that's actually a menu
Hence the "erroneous _impression_" (emphasis added).
I'm curious as to how they decided which models to run which editions on.
Although V4 _ran_ on the /45, split I+D wasn't supported - for user or kernel
- until V6. (I'm assuming a number of things - both in the kernel, and
applications - started hitting the 64KB limit, which led to its support.)
Speaking of split I+D, there's an interesting little mystery in V6 that at
one point in time I thought involved split I+D - but now that I look closely,
apparently not. The mystery involves a 'tombstone' in the V6 buf.h:
#define B_RELOC 0200 /* no longer used */
I had created (in my mind) an explanation what this is all about - but now
that I look, it's probably all wrong!
My explanation involves the slightly odd layout of the kernel in physical
memory, with split I+D; data below the code, at physical 0. This actually
makes a lot of sense; it means the virtual address of any data (e.g. a
buffer) is the same as its physical address (needed for DMA). It does require
the oddness of 'sysfix', to invert the order of code+data in the system
binary, plus odd little quirks in the assembler startup (e.g. copying the
code up to make room for BSS).
So I thought that B_RELOC was a hangover from a time, at the start of split
I+D, when data _wasn't_ at physical 0, so a buffer's virtual and phsyical
addresses differed.
But that must be wrong (at least in any simple way). B_RELOC was in buf.h as
of V4 - the first kernel version in C - with no split I+D. So my theory has
to be wrong.
However, I am unable to find any code in the V4 kernel which uses it! So
unless someone who remembers the very early PDP-11 kernel can enlighten us,
its purpose will always remain a mystery!
Noel
> From: Paul Ruizendaal
> [c] Fifth Edition UNIX PDP-11/40 June 1974
> [d] Sixth Edition UNIX PDP-11/45 May 1975
> [e] Seventh Edition UNIX PDP-11/70 January 1979
This table gives an erroneous impression of which versions supported which
PDP-11 models. 4th Edition supported only the /45; 5th Edition added support
for the /40; and the /70 appeared in 6th edition.
Noel
Sandy Fraser died June 13. The moving spirit behind Datakit, Sandy
served as director then executive director responsible for computing
science at Bell Labs in the era of v8, v9, and v10. He became VP at
AT&T Shannon Labs after the split with Lucent.
Doug
Excited as I was to see this history of Unix code in a single repository:
https://github.com/dspinellis/unix-history-repo
it continues the long-standing tradition of ignoring all the work done at
Bell Labs after v7. I consider v8 v9 v10 to be worth of attention, even
influential, but to hear this list talk about it - or discussions just
about anywhere else - you'd think they never existed. There are exceptions,
but this site does reinforce the broadly known version of the story.
It's doubly ironic for me because people often mistakenly credit me for
working on Unix, but I landed at the Labs after v7 was long dispatched. At
the Labs, I first worked on what became v8.
I suppose it's because the history flowed as this site shows, with BSD
being the driving force for a number of reasons, but it feels to me that a
large piece of Unix history has been sidelined.
I know it's a whiny lament, but those neglected systems had interesting
advances.
-rob
While I know that there are people here who like good old ed...I've been playing with UTS under VM/370. This version is from 1981 and I think it's v7. But the important thing is that Tom Lyon wrote a 3270 terminal driver, and it comes with ned, which is a screen editor that feels a lot like XEDIT--which wasn't even in CMS at that point, although EE has been added to the VM370 Community Edition I'm using. And the man pages are fullscreen as well.
UTS is very, very usable because of that. This really is a wonderful terminal driver.
So, thank you, Tom!
Adam
> I don't know the exact history of RFS a la System V, but I
> don't think it was Peter Weinberger's stuff, and it certainly
> wasn't his code.
Peter’s code is available in the V8 and V9 trees on TUHS.
The Sys V repositories on Github appear to include RFS code in all of R3.0, R3.1 and R3.2.
At first glance, it seems quite different from the V8/V9 code.
> Peter, being a self-described fan of cheap hacks, also wasn't
> inclined to spend much time thinking about general abstractions;
> in effect he just turned various existing kernel subroutines
> (when applied to a network file system) into RPCs. The
> structure of the file system switch was rather UNIX-specific,
> reflecting that.
Yes, well put. I’ve back ported his filesystem switch to V6/V7 and it is very light touch: on the PDP11 it added only some 500 bytes of kernel code (after some refactoring).
With hindsight it seems such a logical idea, certainly in a context where the labs were experimenting with remote system calls in the mid 70’s (Heinz Lycklama's work on satellite Unix) and early 80’s (Gottfried Luderer et al. on distributed Unix — another forgotten version). It is such a powerful abstraction, but apparently very elusive to invent.
Paul
> I can think of at least 4 things, some big, some small, where post-V7
> Research Unix was influential
Besides streams, file system switch, /proc, and /dev/fd. v8 had the
Blit. Though Rob's relevant patent evoked disgruntled rumblings from
MIT that window systems were old hat, the Blit pioneered multiple
windows as we know them today. On the contemporary Lisp Machine, for
example, active computation happened in only one window at a time.
V8 also had Peter Weinberger's Remote File System. Unlike NFS, RFS
mapped UIDS, thus allowing files to be shared among computers in
different jurisdictions with different UID lists. Unfortunately, RFS
went the way of Reiser paging.
And then there was Norman Wilson, who polished the kernel and
administrative tools. All kinds of things became smaller and
cleaner--an inimitable accomplishment
> No clue what was new in V10
This suggests I should put on my to-do list an update of the Research
Unix Reader's combined table of man-page contents, which covers only
v1-v9. I think it's fair to say, though, that nothing introduced in
v10 was as influential as the features mentioned above.
Doug
I don't know the exact history of RFS a la System V, but I
don't think it was Peter Weinberger's stuff, and it certainly
wasn't his code. Nor his name: he called his first version
neta and his second netb (he knew it would be changing and
allowed for it in the name from the start).
I don't remember us ever calling it RFS, or even remote
file systems, inside 1127; we called it network file systems
(never NFS because the Sun stuff existed by then).
For those who don't know it, Peter's goal was quite different
from that of NFS. The idea behind NFS seems always to have
been to mount a remote file system as if it were local, with
a base assumption early on that everything was within the
same administrative domain so it was OK to make assumptions
about userids matching up, and running code as super-user.
Peter described his intent as `I want to be able to use your
disks, and that's a lot simpler if I don't have to get you
to add code to your kernel, or even to run a program as
super-user.' Hence the entirely-user-mode server program,
which could use super-user privileges to afford access as
any user if it had them, but also worked fine when run as
an ordinary user with only that user's file permissions.
We did in fact normally run it as super-user so each of
our 15 or so VAXes could see the file system tree on each
other, but we also occasionally did it otherwise.
That was one reason device files worked as they did, accessing
the device on the server end rather than acting like a local
special file on the client: we didn't care about running
diskless clients, but we did occasionally care about accessing
a remote system's tape drive.
Peter, being a self-described fan of cheap hacks, also wasn't
inclined to spend much time thinking about general abstractions;
in effect he just turned various existing kernel subroutines
(when applied to a network file system) into RPCs. The
structure of the file system switch was rather UNIX-specific,
reflecting that.
That also means Peter's code was a bit ad-hoc and wonky in
places. He cleaned it up considerably between neta and netb,
and I did further cleanup later. I even had a go at a library
to isolate the network protocol from the server proper, converted
the netb server to use it, and made a few demo servers of my own
like one to read and write raw FILES-11 file systems--useful for
working with the console file system on the VAX 8800 series,
which was exported to the host as a block device--and a daemon
to allow a tar archive to be mounted as a read-only file system.
In modern systems, you can do the same sort of things with FUSE,
and set up the same I-want-to-use-your-disks (or I want to get
at my own files from afar without privileges) scheme with sshfs.
I would be very surprised to learn that either of those borrowed
from their ancient cousins in Research UNIX; so far as I know
they're independent inventions. Either way I'm glad they exist.
Norman Wilson
Toronto ON
interesting to know the vax was a complete dead end.
i do remember jmk (rip) reporting on 9fans, maybe even releasing, the vax plan9 kenc compiler he discovered in a dusty corner of the dump filesystem.
I was intrigued and asked if there was anything else, but he said he said there where no kernel or driver fragments to go with it.
-Steve
For those interested in a quick feel for V8 and early SysV, I recommend the excellent unix50 stuff:
SSH to unix50: "ssh unix50(a)unix50.xn--org-9o0a
Password is “unix50”
You end up in a menu with:
SDF Public Access UNIX System presents ...
/~/~/~/~/~/~/~/~/~/~/~/~/~/~/~/~/~/~/~/~/~/~/~/~/~/~/~/
/~/~ H Y S T E R I C A L ~ U N I X ~ S Y S T E M S ~/~/
/~/~/~/~/~/~/~/~/~/~/~/~/~/~/~/~/~/~/~/~/~/~/~/~/~/~/~/
[a] UNICS (Version Zero) PDP-7 Summer 1969
[b] First Edition UNIX PDP-11/20 November 1971
[c] Fifth Edition UNIX PDP-11/40 June 1974
[d] Sixth Edition UNIX PDP-11/45 May 1975
[e] Seventh Edition UNIX PDP-11/70 January 1979
[f] Research UNIX 8 VAX-11/750 1984
[g] AT&T UNIX System III PDP-11/70 Fall 1982
[h] AT&T UNIX System V PDP-11/70 1983
[i] AT&T UNIX System V 3b2/400 1984
[j] 4.3 BSD MicroVAX June 1986
[k] 2.11 BSD PDP-11/70 January 1992
[w] What's running now?
[q] QUIT (and run away in fear!)
User contributed tutorials are at https://sdf.org/?tutorials/unix50th
Want persistent images? networking? more ttys? Join https://sdf.org
Don’t to exit from a run, press Ctrl-E to return to sims, type 'exit', type ‘q'
I just tried V8 and it still works, although the boot log suggests that an image reset may be in order.
Many, many thanks to whoever is maintaining this!
