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From: maarten@fwi.uva.nl (Maarten Carels)
Newsgroups: comp.sys.mac
Subject: Re: IIci/Ehman Hard Drive Problems
Keywords: IIci Ehman 80+ meg hard drive external system death
Message-ID: <362@fwi.uva.nl>
Date: 9 Jan 90 23:08:45 GMT
References: <1299@milton.acs.washington.edu>
Sender: news@fwi.uva.nl
Lines: 36

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?

This looks if the driver on your hard disk is incompatible with the ci.
The sad mac is nothing more than a system error (bomb) if the system error
handler is not yet installed (it is not until the system file is opened).
So, it seems a bomb ID=01 (Bus Error), the driver is accessing nonexistant
memory.

The solution is to upgrade the driver on the disk by using the newest
version of the installer program (or yell at Ehman if the newest version
contains a driver with this behaviour.

As the plus is a much more simple machine, bugs in drivers (and other software)
have less chance to cause problems.

As an aside, the ci is the first mac to correctly check checksums on SCSI
drivers, but the only effect of a bad checksum is that the driver will not load
(because the system thinks it is damaged). It will not cause sad macs or other
crashes as you describe (That is what the check is for, anyway...).

--maarten
In real life:	Maarten Carels
		Computer Science Department
		University of Amsterdam
email:		maarten@fwi.uva.nl