24 Feb
2008
24 Feb
'08
7:53 a.m.
Zane H. Healy wrote:
At 4:15 PM +0000 2/23/08, Martin Bishop wrote:
Jerome Fine replies:
I have never found a CDROM that was usable - never tried that hard.
I have had good experience for disk drives with the CQD-220/TM
and a friend of mine with the UC07 (if I remember the number - I
don't think it was the UC02, but I could be wrong).
The Dilog SQ706A did not work, but that was 15 years ago when
it was brand new and there was a firmware bug - which Dilog
knew about, but would not fix promptly enough to use. Actually
the CQD220/TM had the same firmware problem, but I had a fixed
working EPROM with the revised firmware in 2 weeks! In both
cases, the bug was a buffer which overlapped a 256 KByte boundary
in physical memory on the Qbus. Since my test program used
6 * 24 KByte buffers, there was a high probability that one
buffer would overlap a 256 KByte boundary.
Sincerely yours,
Jerome Fine
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What I'm curious to know is:
- What boards were made and which are commonly available
e.g. DEC KZQSA, CMD CDQ-220, Dilog SQ706 ?, Emulex UC02 ?, Andromeda
SCDC-11 ?, ...
- The relative (to SCSI 1) performance of each of the boards
- Which boards are "dogs" : gotchas, tape only, unreliability /
electronics failures
The Viking QDT (disk/tape also available as tape or disk only) aren't
the fastest boards out there (I think those are the CMD boards), but
they're good rock solid boards. With the most recent versions of
firmware they should work good with a CD-ROM. While I use mine in
PDP-11's, I'm thinking about putting one in a MicroVAX III (I want to
move off RA72's and RA73's). I typically have Seagate 2GB
Barracuda's, a Plextor 8x CD-ROM, and either a TZ30 or TLZ06 (4mm)
attached. I've also used a 2x DEC CD-ROM, and IBM 100Mb and 200MB
SCSI drives in the past.