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.)
John Reiser did do his own paging system for UNIX 32/V.
I heard about it from friends at Bell Labs ca. 1982-83,
when I was still running systems for physicists at Caltech.
It sounded very interesting, and I would love to have had
my hands on it--page cache unified with buffer cache,
copy-on-write from the start.
The trouble is that Reiser worked in a different group
from the original UNIX crowd, and his management didn't
think his time well spent on that work, so it never got
I remember asking, either during my interview at the Labs
or after I started work there, why the 4.1 kernel had been
chosen instead of Reiser's. It had to do with maintainability:
there were already people who could come in and hack on the
Berkeley system, as well as more using it and maintaining it,
whereas Reiser's system had become a unicorn. Nobody in
1127 wanted to maintain a VM system or anything much close
to the VAX hardware. So the decision was to stick with a
kernel for which someone else would do those things.
Once I'd been there for a year or so and settled in, I found
that I was actually looking after all that stuff, because I
was really interested in it. (Which seemed to delight a lot
of people.) Would we have ended up using Reiser's kernel had
I been there a couple of years earlier? I don't know.
It is in any case a shame that jfr's code never saw the light
of day. I really hope someone can find it on an old tape
somewhere and we can get it into the archive, if only because
I'd love to look at it.
On 8/28/19, Clem Cole <clemc(a)ccc.com> wrote:
> On Wed, Aug 28, 2019 at 2:46 AM Peter Jeremy <peter(a)rulingia.com> wrote:
> Tru64 talked to DECnet Phase X (I don't remember which one, maybe 4 or 5),
> which had become an ISO/OSI stack by that point for political reasons
> inside of Digital (the OSI vs TCP war reminded me of the Pascal vs C and
> VMS vs UNIX wars - all very silly in retrospect, but I guess it was really
> about who got which $s for development).
It was DECnet Phase V that was based on the ISO/OSI stack. IIRC, at
the time the European telcos were pushing OSI, it had become an ISO
standard, etc. etc. It was also pretty easy to compatibly slide the
legacy proprietary DECnet Phase IV adaptive routing and virtual
circuit layers into the OSI stack.
TCP won the war, of course. The risk with international standards
fashioned out of whole cloth by a committee (as opposed to being a
regularization of existing practice) is that the marketplace may
choose to ignore the "standard". OSI and the Ada programming language
are cases in point.
Leaving licensing and copyright issues out of this mental exercise, what
would we have now if it wasn't for Linux? Not what you'd WANT it to be,
although that can add to the discussion, but what WOULD it be?
I'm not asking as a proponent of Linux. If anything, I was dragged
kicking and screaming into the current day and have begrudgingly ceded
my server space to Linux.
But if not for Linux, would it be BSD? A System V variant? Or (the
horror) Windows NT?
I do understand that this has been discussed on the list before. I
think, however, it would make a good late-summer exercise. Or late
winter depending on where you are :)
the other early vm system not mentioned yet is the one Charles Forsyth wrote at the university of york for sunos. i never used it as i was learning v7 on an interdata 30 miles away at the time but i read his excellent paper on it.
Check out "Setting Up a Research UNIX System" by Norman Wilson. troff
sources are in v10.
But that assumes you're being given a root image to copy
to the disk initially, no? We never made a general-purpose
distribution tape; we just made one-off snapshots when someone
wanted a copy of the system in the 10/e era.
Is there a binary root image in Warren's archive? I forget.
(where the weather feels like NJ these days, dammit)
i went for a student placement there but didnt get it - i guess my long hair (then) didn't fit as the interview seemed good.
i had a mate who was working late on the day the combined uk police and CIA (it was said) arrived to shut them down, and tell them they ARE being taken over by CDC. the crime was selling systime re-badged vaxes to the ussr at the height of the cold war. seem odd now that they thought they could get away with it.