20 Apr
2018
20 Apr
'18
6:33 p.m.
On Fri, Apr 20, 2018 at 10:12 AM, Dan Cross <crossd(a)gmail.com> wrote:
That's a bit different. It's possible that
some early Unix machines had
actual drum devices for storage or swap (did any of them?), but the
/dev/drum device is what Clem says it was.
It's funny, I just happened across this a couple of days ago when I went
looking for the `hier.7` man page from 4.4BSD-Lite2:
https://www.freebsd.org/cgi/man.cgi?query=hier&apropos=0&
sektion=7&manpath=4.4BSD+Lite2&arch=default&format=html
It refers to this: https://www.freebsd.org/cgi/man.cgi?query=drum&
sektion=4&apropos=0&manpath=4.4BSD+Lite2
The claim is that it came from 3.0BSD. Why was it called drum? I imagine
that's historical license coupled with grad student imagination, but I'm
curious if it has origin in actual hardware used at UC Berkeley. Clem, that
was roughly your era, was it not?
http://www.tuhs.org/cgi-bin/utree.pl?file=3BSD/usr/src/sys/sys/vmdrum.c
So there's something called drum in 3BSD. Haven't chased down the MAKEDEV
and config glue to turn it into /dev/drum, but it's enough to support the
'It originated in 3BSD'. It certainly wasn't in 32V since that had no
paging.
This was 1980. Drum memory stopped being a new thing in the early 70's. So
it was just recently obsolete. But its typical use was a very small, but
very fast, hard drive to swap things to. There never was a drum device, at
least a commercial, non-lab experiment, for the VAXen. They all swapped to
spinning disks by then.
Warner
- Dan C.
On Fri, Apr 20, 2018 at 12:00 PM, David Collantes <david(a)collantes.us>
wrote:
I found a Wikipedia[0] entry for it.
[0] https://en.m.wikipedia.org/wiki/Drum_memory
<https://en.m.wikipedia.org/wiki/Drum_memory?wprov=sfti1>
--
David Collantes
+1-407-484-7171
On Apr 20, 2018, at 11:02, Tim Bradshaw <tfb(a)tfeb.org> wrote:
I am sure I remember a machine which had this (which would have been
running a BSD 4.2 port). Is my memory right, and what was it for
(something related to swap?)?
It is stupidly hard to search for (or, alternatively, there are just no
hits and the memory is false).
--tim