Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!wuarchive!cs.utexas.edu!uunet!mcsun!hp4nl!fwi.uva.nl!dolf
From: dolf@fwi.uva.nl (Dolf Starreveld)
Newsgroups: comp.sys.mac
Subject: Re: IIci/Ehman Hard Drive Problems
Keywords: IIci Ehman 80+ meg hard drive external system death
Message-ID: <361@fwi.uva.nl>
Date: 9 Jan 90 22:35:03 GMT
References: <1299@milton.acs.washington.edu>
Sender: news@fwi.uva.nl
Lines: 34

phaedrus@milton.acs.washington.edu (The Wanderer) writes:
>      I'm soon to be purchasing a Mac IIci (finally got tired of waiting for my
> Plus to compile...)  I have an 80+MB external Ehman hard drive, which I'd
> certainly like to keep using (read, MUST keep using).  But when I tried to
> connect it to a couple of ci's, all I got was a pretty error chord and a sad
> Mac (error code=0000000F,00000001).
>      I seem to recall that this could be caused by the fact that the ci is the
> first Mac to check the checksums of SCSI drivers, and some drivers have 
> invalid checksums.  I also seem to recall that this checksum check could be
> disabled by using Resedit to change the name of the driver in a certain way.
> Unfortunately, I can't find any articles explaining just how.  Could someone
> help me out on this?
If this is indeed the reason (it might very well be), it can be fixed thusly:
Use any program that allows you to access logical blocks on a SCSI drive.
Note that this is not ResEdit and certainly is not the same as a regular
disk editor such as FEdit which can only edit blocks of Macintosh volumes.
Suitable programs are Apple's SEdit, SUM Tools and may be some other too.
Look for a block somewhere in the beginning of the disk which belongs to the
partition map. The partition map usually starts at block 1 and continues for
some 5 to 20 blocks. Each block should begin with the two character 'PM'.
One of those blocks should contains two strings:
"Macintosh...." and "Apple_Driver" (the ... means it can be anything, only the
"Maci" parti is important.
In this block, change the 'M' in "Maci" to anything else and the checksum
code will not be exercised.

Hope this helps you..

--dolf

Dolf Starreveld  Phone: +31 20 592 5056/5022 (FAX: 5155), TELEX: 10262 HEF NL
EMAIL:           dolf@fwi.uva.nl (dolf%fwi.uva.nl@hp4nl.nluug.nl)
SNAIL:           Dept. of Math. and Computing Science, University of Amsterdam,
                 Kruislaan 409, NL-1098 SJ  Amsterdam, The Netherlands