Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!apple!bloom-beacon!spdcc!dyer
From: dyer@spdcc.COM (Steve Dyer)
Newsgroups: comp.sys.ibm.pc.rt
Subject: ESDI disks for RT (AOS 4.3)
Message-ID: <3396@ursa-major.SPDCC.COM>
Date: 29 May 89 14:58:05 GMT
Reply-To: dyer@ursa-major.SPDCC.COM (Steve Dyer)
Organization: S.P. Dyer Computer Consulting, Cambridge MA
Lines: 39

I've asked this before, but now I have some bad experience which I'd
like to share, and hopefully get some information in return.

The cost of IBM ESDI disks is completely out of line with my budget, so
I've been looking at less expensive means of upgrading my machine.
The hd.c disk driver looks fairly flexible at accepting disks of varying
geometries, and in fact I've used a number of different ST506 disk drives
with the AT disk controller.  I hoped that the same would be true for the
EEDSI controller.

I purchased a Miniscribe 9380E 300mb disk drive.  Unfortunately, there
seems to be a fatal incompatibility between it and the IBM EESDI
controller:  not only will the drive fail to be recognized at the very
outset ("can't init drive") by the AOS 4.3 format program, but the act
of attaching the controller to the drive seems to destroy something in
the drive electronics.  For example, a drive which formats OK on a 386
system will no longer work after it's been attached to the RT's EESDI
controller.  This has been verified with two different Miniscribe units.

Since the IBM H310 drive is (I thought) simply a repackaging of the Maxtor
4380E, I obtained one of these.  I set the jumpers identically to existing
H310 drives in accordance with the IBM installation manual, and proceeded
to format the drive.  It gave a write error on each track (sector=1 SCT=34),
and one which didn't disappear with repeated formats, and the drive gave
errors trying to run newfs under AOS 4.3.  This was attempted on two
different RT systems, jumpers inspected by different individuals, and the
results were identical.  There has been talk of the need for a shortened
index pulse by the IBM controller, but a Maxtor support person in Austin
told me that recent drives (which this one is) shouldn't need any modification.
I'll be trying another unit shortly to ensure that this isn't a sample
defect, but I am puzzled.

Anyway, thank God for a patient dealer.  Be careful out there.  If I have
any good news, I'll pass it on.

-- 
Steve Dyer
dyer@ursa-major.spdcc.com aka {ima,harvard,rayssd,linus,m2c}!spdcc!dyer
dyer@arktouros.mit.edu