31 Aug
2019
31 Aug
'19
2:21 a.m.
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
released.
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.
Norman Wilson
Toronto ON