Q-bus SCSI Controllers RFI
Jerome H. Fine
jhfinedp3k at compsys.to
Sun Feb 24 06:53:17 CST 2008
>Zane H. Healy wrote:
> At 4:15 PM +0000 2/23/08, Martin Bishop wrote:
>> 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.
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.
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