Adaptec ACB-2372 and Everex 386/20. Was (Adaptec controller/Miniscribe 6085?)

[Larry Dighera]

In article <569 at vector.UUCP> chip at vector.UUCP (Chip Rosenthal) writes:
>
>am trying to run SCO XENIX 386 2.2 on an Everex Step 386/20 with a
>Miniscribe 6128 and an Adaptec ACB2372.  I've been having all sorts of
>problems -- usually paging system panics but occasionally a general
>protection trap.  My initial best guess was either a disk or memory
>problem.

I have successfully run the Adaptec ACB-2372 controller under SCO 
XENIX-386 on the Everex 386/20 with 4 MB of RAM using Maxtor XT1140 and
XT1085 drives.  After several months of operation there are no
anomlys to report.  The only possible cause for your difficulty that 
comes to mind is the speed of the expansion bus.  There is a jumper
on the mother board that facilitates selection of 6.75 or 10 MHz
bus operation.  Jumper W17, located at the rear of the left hand 
drive bay, selects 6.75 MHz bus speed when installed.  If jumper
W17 is removed on your system, that may be the source of the difficulty.

You should also be aware that Adaptec has issued a bulletin on using 
ACB-23XX controllers with SCO Xenix.  It basicly states that you
do the low-level format with: debug g=C800:5 under PC-DOS, then
using the same program on the Adaptec ROM, create a single 
partition that contains all of the available cylinders on the drive.
You can request this bulletin by contacting Judy Gavin at (408) 945-8600.

>We ran Everex's memory diagnostics for two days.  No problems found.

I have found the utilities supplied by Everex to be worthless.  The 
drive formating software in particular was newer than the documentation
and did not perform correctly.  

>We screwed around with the Adaptec strappings for a bit with no improvement.
>Specifically, we messed around with the J14 strap for wait states and
>the J12 straps for BIOS selection.

I used the default controller strapping options even though some of them
didn't seem correct for my hardware.  In particular the seek past cylinder
0 and C&T wait state jumpers didn't seem appropriate, but all works fine.

>We then swapped it out for a plain old WD 1:1 MFM controller.  Problems
>went away.

I was thinking of using the WD1006RAH 1:1 RLL controller (which has
no floppy support) and a seperate WD1002A FOX F004 floppy controller
card (which will handel 4 floppy drives) so that I could install a 
3-1/2" floppy in addition to the 1.2 MB and 360 KB drives.  If anyone
has done this, I would be interested in knowing what is involved in
terms of device drivers for the additional floppy drives.

Larry Dighera

[Please disregard the numerous spelling errors.  It's late/early, and
I'm not fully awake yet. :-)]
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