Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!hplabs!hpfcdc!hpislx!bfc
From: bfc@hpislx.HP.COM (Bryan Carpenter)
Newsgroups: comp.sys.mac
Subject: Need Hard Drive Info
Message-ID: <5880007@hpislx.HP.COM>
Date: 3 Apr 89 21:07:44 GMT
Organization: HP Measurement Systems Operation - Loveland, CO
Lines: 27


I have a Supermac Dataframe XP20 that has developed a worsening habit of
not spinning up when the power is turned on.  The drive inside is a 3.5
inch Miniscribe model 8425.  I talked to Supermac tech support, and they
recommended that I could use a Seagate ST-225 as a replacement, as that
was one of the drives that they used in the XP20.

I would prefer to replace it with a Seagate ST-125, which is a 3.5"
20 Meg drive.  All of these drives, the ST-225, the ST-125, and the
Miniscribe 8425 have the same number of heads, sectors, and cylinders,
but they are spec'ed differently for write precompensation as follows:

Miniscribe 8425: cylinder 128
Seagate ST-225:  cylinder 300
Seagate ST-125:  none

Since the info I got from Supermac seems to indicate that either of the
first two drives can be used without changing anything in the controller,
can I assume that the ST-125 could be used also?  I assume that the
controller is currently using write precompensation of some sort.  Does
anyone know if the use of write precomp on a drive that doesn't call for
it will foul up the integrity of the written data?

Thanks in advance for any info you can give me.

Bryan Carpenter
bfc%hpisla@hplabs.hp.com