I've assembled some notes from old manuals and other sources
on the formats used for on-disk file systems through the
Additional notes, comments on style, and whatnot are welcome.
(It may be sensible to send anything in the last two categories
directly to me, rather than to the whole list.)
What's the current status of net/2?
I ask because I have a FreeBSD 184.108.40.206 CVS repo that I'd like to make
available. Some of the files in it are encumbered, though, and the
University of California has communicated that fact. But what does that
actually mean now that V7 has been released and that's what the files were
based on? Are they no longer encumbered?
> From: Paul Guertin
> I teach math in college ... Sometimes, during an exam, a student who
> forgot to bring their calculator will ask if they can borrow mine I
> always say "sure, but you'll regret it" and hand them the calculator
> After wasting one or two minutes, they give it back
Maybe I'm being clueless/over-asking, but to me it's appalling that any
college student (at least all who have _any_ math requirement at all; not sure
how many that is) doesn't know how an RPN calculator works. It's not exactly
rocket science, and any reasonably intelligent high-schooler should get it
extremely quickly; just tell them it's just a representational thing, number
number operator instead of number operator number. I know it's not a key
intellectual skill, but it does seem to me to be part of comon intellectual
heritage that everyone should know, like musical scales or poetry
rhyming. Have you ever considered taking two minutes (literally!) to cover it
briefly, just 'someone tried to borrow my RPN calculator, here's the basic
idea of how they work'?
When googling for File System Switch or Virtual File System most sources mention Sun NFS and SysVr3 as the earliest implementations. Some sources mention 8th Edition.
I did a (short) search on FSS/VFS in earlier, non-Unix OS’s (Tenex, Multics, CTSS, etc.), but none of those seem to have had a comparable concept.
Does anybody recall prior art (prior to 1984) in this area?
All, I just received this e-mail from a non-TUHS list member. If you have
an answer for Michael, could you reply to him and pop a cc here as well?
----- Forwarded message from Michael Siegel <msi(a)malbolge.net> -----
Date: Sun, 14 Jun 2020 16:37:59 +0200
From: Michael Siegel <msi(a)malbolge.net>
Subject: Origins and life of the pg pager
I'm trying to find out where the pg pager originated.
The research I've done so far vaguely suggests it came with one of the
System V versions, though Internet claims it to be “the name of the
historical utility on BSD UNIX systems” occasionally.
I think System V because the source code of pg.c in the util-linux
package says that this utility is “a clone of the System V CRT paging
I'd also like to find out when pg was discarded and if it ever made it
into POSIX before that. Linux still has pg to the very day, but none of
the current major BSDs (Free/Net/Open) offer it. POSIX 2001, 2004
Edition lists it as an excluded utility. I've not been able to get
the text of any prior POSIX documents. It seems they aren't freely
Any ideas on how to proceed?
 This one's from Wikipedia (https://en.wikipedia.org/wiki/Pg_(Unix)),
but I've also found other sites stating the same.
----- End forwarded message -----
Date: Wed, 24 Jun 2020 14:31:34 -0400 (EDT)
From: norman(a)oclsc.org (Norman Wilson)
> 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
I am still digesting all the inputs (thanks, all!)
The above post made me realise that the delineation of what is a FSS/VFS or not, is not so easy.
I did a little bit of reading, and the concept of an ACP arrived with RSX11D in May 1973, but only matured in RSX11M in November 1974. As I understand it, originally in RSX11 file system code was closely tied to the low-level device driver for each device. ACP’s separated the file system code from the device driver itself, and became separate processes.
In essence there were two switches: one switch into abstract devices, implemented in ACP code and one kernel switch to deal with hardware interfacing. The first is indeed like a file system switch (although still tied to specific devices).
Looking at this stuff made me realise that my retro machine of choice (the TI990) went through a similar evolution. In the early seventies it had a sort of abstract device switch that linked to individual ‘device service routines’ (drivers). Initially, these modelled batch oriented ‘logical units’ that tied to files at the job control level. Later (late 70’s), the ‘open’ command would carry a file name and the file system was delegated to the device service routine. Still later (say 1983) this was used for networked disks.
As several people have observed in this topic, indeed there appears to be a close relationship between a device switch and a file system switch.
Anybody on the list know much about the provenance of SVr4 and OKIX for the
Okistation 7300 model 30?
http://museum.ipsj.or.jp/en/computer/work/0029.html indicates that OKIX
came later on the model 75, but many years ago as a staff programmer at
Oregon Graduate Institute, a surplus 7300/30 followed me home, but the
sysadmins referred to it as OKIX.
if anybody's interested in the hardware to do some spelunking, email me
Aaron J. Grier | "Not your ordinary poofy goof." | agrier(a)poofygoof.com
"The price of reliability is the pursuit of the utmost simplicity. It
is a price which the very rich find most hard to pay." -- Tony Hoare