From mboxrd@z Thu Jan 1 00:00:00 1970 From: imp@bsdimp.com (Warner Losh) Date: Fri, 20 Apr 2018 10:33:04 -0600 Subject: [TUHS] /dev/drum In-Reply-To: References: <8225C5DB-27BD-464E-930A-522C30C20EBD@tfeb.org> <25A1FED0-4F8B-408F-B27B-5728C649D8BE@collantes.us> Message-ID: On Fri, Apr 20, 2018 at 10:12 AM, Dan Cross 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 > wrote: > >> I found a Wikipedia[0] entry for it. >> >> [0] https://en.m.wikipedia.org/wiki/Drum_memory >> >> >> -- >> David Collantes >> +1-407-484-7171 >> >> On Apr 20, 2018, at 11:02, Tim Bradshaw 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 >> >> > -------------- next part -------------- An HTML attachment was scrubbed... URL: