> From: Rob Gingell
> RSEXEC (Resource Sharing EXEC) done on TENEX earlier in the 1970s.
That was associated with the National Software Works project:
https://apps.dtic.mil/dtic/tr/fulltext/u2/a132320.pdf
I think? (It's been four decades since I looked at NSW, so I don't recall
much about it.) Neither was TENEX-specific; e.g. there were Multics
implementations of RSEXEC and NSW.
Noel
> From: Richard Salz
> A web search for "its mldev" finds several things (mostly by Lars
> Brinkhoff it seems)
Yeah, other than the source:
https://github.com/PDP-10/its/blob/master/src/sysen2/mldev.106
there's not a lot on it.
That's typical of a lot of the innovative work done at the AI Lab, LCS, etc;
they built some extraordinary tools, but to them they were just tools they
used to work on their research, their _real_ work. So why bother to write that
stuff up? So people who actually used them remember them, but other than
that...
Welcome to tomorrow, where everything gets re-invented, because everyone is too
busy to waste time learning about the past.
Noel
> From: "Greg A. Woods"
> as Organick said in his 1972 book
A word of warning: i) Organick describes Multics as it was planned, not as it
was actually implemented; and ii) then it changed considerably during its
service life.
Examples of each: i) there was one linkage segment per processs, not per
segment (linkage info was copied across into the shared linkage segment when a
segment was dynamically added to a process' address space); ii) the New Storage
System.
The basic concepts (single level store, dynamic linking etc) are correct in
Organick, but be wary of anything past that. Not his fault, of course; things
just changed.
> As far as I can remember Multics didn't really have the concept of a
> "mount point".
In the original design, no. In 1973-75, with the New Storage System:
https://multicians.org/nss.html
mountable volumes were added (see MTB 229, "Use of Demountable Logical
Volumes", linked from the page above). It was released to customers in
June, 1976.
Noel
Reaching outside of UNIX, RSX/11 used external
supervisor-mode processes called ACPs (ancillary
control processes) to implement file systems.
I don't know exactly how they were plugged in,
but I do know they were pluggable, so their
interface must have constituted a file-system
switch of some sort. RSX dates back into the
1970s.
At some point in the latter part of the 1980s,
Ralph Stamerjohn (a name instantly recognizable
in the 16-bit DEC software world) gave a DECUS
talk about implementing a remote file system
through ACPs: a stub ACP on the client exporting
RPCs over the network, a real one at the server
end. I remember chatting with him about how
that did and didn't resemble the way pjw had
done it; interesting architectural comparison.
Norman Wilson
Toronto ON
> From: Anthony Martin
> wherein they state the following:
> A virtual file system, from the viewpoint of application programs on a
> computer, models the file system functions of other computers. This is
> done in the same way as with virtual terminals, a virtual file system
> consists of a UPP having virtual files (VF), and a UCP which executes
> virtual file system protocols.
> I'd be interested if you find anything earlier.
MLDEV on ITS would, I think, fit under that description.
I don't know if there's a paper on it; it's mid-70's.
Noel
> From: Dave Horsfall <dave(a)horsfall.org>
> Ioctl: the Swiss Army knife of system calls. I thought it was a neat
> idea when it arrived (much better then those primitive stty/gtty calls)
> but now...
Like they say, when the only tool you have is a hammer...
Better syntax than stty/gtty, maybe but I'm not sure the semantics are that
much better. The problem is that, especially with devices, what the I/O
commands do is so widely varied that it's hard to fit them all under a
unified umbrella. Maybe some (e.g. asynchronous I/O), but not all.
Noel
There is an interesting paper that Dennis Ritchie and Dave Presotto wrote, “Interprocess Communication in the Ninth Edition Unix System” (https://www.bell-labs.com/usr/dmr/www/ipcpaper.html <https://www.bell-labs.com/usr/dmr/www/ipcpaper.html>).
This appears to be an update of a paper that they wrote in 1985, “Interprocess Communication in the Eighth Edition Unix System”. This earlier paper is hard to find.
Anybody on this list who has it on hand?
Rob Pike:
For my taste, the various Unix file system switches that I've seen are too
firmly tied to the idea of blocks and disks and all that, making them less
flexible than they should have been. That's why the Plan 9 version is about
names and byte streams, to make it as general as possible.
=====
The only file-system switch I know well is that in the later
Research systems. It has nothing to do with disks or blocks.
It is about names and inodes: turn name to struct inode, read
arbitrary chunk of data, write arbitrary chunk of data, create
file, unlink file, abominable ill-defined system call that just
wouldn't die erm I mean ioctl, and so on.
It was certainly a cheap hack (as its author cheerfully admitted)
but it really was about I/O operations, not about simulating
disks. That's why it so easily supported /proc (the one that
was just about processes, not the misnamed Linux one that
is really about all things in the kernel so you don't need
/dev/kmem).
I don't know a lot about later VFSes like those in SunOS or
Linux or the BSDs. Blockiness might well have crept in in
support of memory-mapped I/O or in collaboration with the
buffer-cache implementation. The Research version was never
used directly to support different on-disk file system formats
(we did a different pjw cheap hack for the one case that
mattered in the kernel, and used the idea later developed
more by FUSE for other cases because speed didn't matter).
Norman Wilson
Toronto ON
> From: Michael Siegel
> there's no need to write out "less" every time. You can just alias that
> to "pg" without causing any harm and save two letters, which is an
> improvement for a task that is performed manually rather often.
It always surpised me that there wasn't more of this - abbreviating the names
of the most-used commands, to minimize typing - or more specifically,
run-length encoding them based on how frequently they were used, with the
most-used ones given the shortest names.
The MIT-DSSR PWB1 system had a pager called just 'p' (source here:
http://ana-3.lcs.mit.edu/~jnc/tech/unix/s2/p.c
if anyone wants to see it; the man page is dated Apr/77); and 'ls' was tweaked
to recognize the command name 'l' as an alias for 'ls -ls'.
Of course, aliases didn't exist in the shell back then, which was why the
command had to be coded to recognize the short form, and act differently.
(And /bin/l was linked to /bin/ls.)
'l' and 'p' are _still_ aliased in my shell,to this day!
> I hope it's okay that I chose to reply just to the list address and take
> all the other addresses out.
'That's not a bug, that's a feature!'
I always delete other addresses when replying to a list, unless I think someone
might not be subscribed to that list.
Noel
