8" drives and Compaticard / Uniform

From: Richard Erlacher <edick_at_idcomm.com>
Date: Tue Dec 14 10:55:44 1999

Aside from removing one of the 8" drives from the daisy-chain, the only
thing I can recommend is to look very carefully at the way in which each
signal is used on the cable. My own recollection of the cabling details as
applicable to 8" drives is that the Compaticard really doesn't want you to
have more than one of them. That, in fact, is the reason why I owned one
for ten years and didn't use it.

If you look at the combination of signals used on the CompatiCard and then
look at how the various drive types will interpret them, that should help
you to understand how the card is selecting the "wrong" drive.

As far as jumpering your drives, I'd suggest you use the most restrictive
set of qualifiers that you can come up with, in order to avoid ambiguous
selects. The PC software is geared to using the signals on the cable in a
"strange" way due to the cute fix they (IBM) thought up for their internaly
twisted cable. IIRC, the cable was twisted such that each drive will see
the "motor on" signal as DS1 (based on numbering from 0) . The '860's have
a "motor-on" signal as well, though it shouldn't be used as it is in the
PC-style environment. The drives need to be set up such that their activity
LED only comes on when the drive is selected AND ready. That way, you will
have an external indicator that the READY signal is valid on the cable. The
PC doesn't use this as a ready, since some mini-drives don't generate it
correctly, but it may help you to see what's actually going on. I don't
suggest that you change the jumpering on the 5-1/4 or 3-1/2" drives because
they tend to vary too much. If they work, that's enough to contend with for
now.

Dick

-----Original Message-----
From: Bob Stek <bobstek_at_ix.netcom.com>
To: Discussion re-collecting of classic computers
<classiccmp_at_u.washington.edu>
Date: Tuesday, December 14, 1999 4:28 AM
Subject: RE: 8" drives and Compaticard / Uniform


>-----Original Message-----
>From: CLASSICCMP-owner_at_u.washington.edu
>[mailto:CLASSICCMP-owner_at_u.washington.edu]On Behalf Of Don Maslin
>Sent: Tuesday, December 14, 1999 12:37 AM
>To: Discussion re-collecting of classic computers
>Subject: Re: 8" drives and Compaticard / Uniform
>
>Bob, UniForm will only permit you to identify/select a single copy of
>each type drive - that is 350k, 1.2mb, 3.5" (either 720k or 1.44mb) and
>8". I assume that you used Uinstall to make that identification. About
>the only way that I can think of that you could slip in a second 8"
>drive would be to identify it as a 1.2mb drive - assuming that you do
>not have one.
>
>I might note that 22Disk will permit you to use both 8" drives.
>
> - don
>
>The problem isn't that I want two CP/M drives. It is that I can't access
>even one! The Compaticard seems to have no problem attaching the two
8"-ers
>as MS-DOS drives; I can access them as drives D: and E: just fine. When I
>run Uniform and choose an 8" CP/M format, it tells me that drive F: is now
>my CP/M drive. If I then do a DIR of F:, my drive B: activity light comes
>on and gives me an error message. Even though I have the Compaticard
>jumpered as the quartiary controller (I/O ports 3e0-3e7) Uniform accesses
>drive #2 on the primary controller as drive F:
>
>I suppose that I can disable the second 8" drive and see what happens. I
>will try 22disk as well (although that's only to be pragmatic - I want to
>know why the _at_#%$@#^& thing is acting the way it does!)
>
>
>Bob Stek
>bobstek_at_ix.netcom.com
>Saver of Lost SOLs
>
Received on Tue Dec 14 1999 - 10:55:44 GMT