Subject: Re: strange disks...
To: None <mxs46@po.CWRU.EDU>
From: Tim Shoppa <shoppa@alph01.triumf.ca>
List: port-vax
Date: 12/30/1997 06:41:48
> Third-party
> (primarily Emulex and Dilog) MSCP controllers are very popular, as they

Of the companies that sell Q-bus and Unibus MSCP controllers, I think
the only ones still intact are Dilog, Andromeda, and CMD.

> support interfaces that DEC doesn't, including ESDI, SMD, and even SCSI.

Well, even DEC supports SCSI on MSCP, if you count the RQZX1 which they
sell (but don't manufacture...)

> digits and thus can be interpreted as a DEC disk model number. Since MSCP
> is in its nature hardware-independent, you don't need to know the MSCP ID
> in order to use the disk, it's only for stupid VMS identification purposes.

VMS actually doesn't care at all, except in the SHOW DEV display.
Some other DEC OS's - notably RSTS/E - can be much more picky.  Some
versions of RSTS/E will even require that a device that reports itself
as a RA81 have the right number of blocks to be a RA81...

> Prejudice-free operating systems like Berkeley UNIX(R) and NetBSD don't use
> it at all.

Then how come "disklabel" still insists on knowing device geometry,
to the continuing distress of everyone using block-addressable disks?
Some of the *worst* advice I've seen on the port-vax mailing list
makes it seem that many still believe this information is important :-(
I think it ought to be completely banished from the disklabel process
for MSCP disks, as the geometry is so hidden behind the interface
that it's difficult to use this information for performance purposes
(i.e. seek ordering.)  Besides, MSCP controllers do their own seek
ordering, so the OS shouldn't have to screw around with this!

> total of 7 of them, although I don't know whether all of them actually work
> (but I know that at least some do). There is one Fujitsu M2392K and two CDC
> 9720-1230s. There are two more 9720s, but I don't know the capacity.
> Finally, there are two drives completely unknown. The two 9720s of unknown
> capacity and the two completely unknown drives are mounted in cabinets and
> I haven't taken them out yet, so there still may be a sticker that I
> haven't seen yet. Anyway, I don't have any documentation for any of them,
> and I need it, so if anyone has any documentation for any 8" SMD
> Winchesters, I would greatly appreciate a copy.

I've got about 4000 pages of documentation on various SMD drives, so
unless you want to see a truck pulling up at your door, you might
want to narrow down your search :-).  (Most of my books are Fujitsu
tech manuals.)

> >Is your Emulex
> >controller a QD32, QD33, QD35, or something similar?  These are common
> >SMD to MSCP adapters and ought to work just fine.
>    By the way, does anyone know whether can I get one of those? One can buy
> Dilog DQ256 (quad-height form factor, supports 4 drives) brand new for
> $1825, but that's too expensive. I'm sure one can buy an old SMD controller
> for much cheaper.

Most of the DEC resellers (i.e. Newman, Continental Computers, etc)
will have used Emulex QD32's/33's available.
Price depends on how you ask for it :-).  If the reseller knows
you need a QD33 (will issue seeks on multiple SMD drives) and not
a QD32, expect to pay more!

Tim. (shoppa@triumf.ca)