Path: utzoo!mnetor!tmsoft!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!asuvax!noao!arizona!dave
From: dave@cs.arizona.edu (Dave Schaumann)
Newsgroups: comp.sys.amiga.misc
Subject: Re: Problems with A590 and Excellence
Message-ID: <1272@caslon.cs.arizona.edu>
Date: 28 Mar 91 00:37:07 GMT
References: <3024@redstar.cs.qmw.ac.uk>
Organization: U of Arizona CS Dept, Tucson
Lines: 32

In article <3024@redstar.cs.qmw.ac.uk> msc_ap@cs.qmw.ac.uk (Poon) writes:
>I recenetly purchased the A590 Hard drive + 2Megs of ram for my A500. With the 
>A590 installed I have noticed some programes will not work, to name a few are 
>VirusX4.0, ZeroVirus and Excellence....
>
>Virusx4.0 crashes the machine with a software error as soon as it starts up.
>ZeroVirus and Excellence crashes the machine when it trys to open a file 
>requester.
>
>Does anyone else had the same problem and is there anyway of fixing it. I have 
>read in somewhere that this is to do with the FastFileSystem file in the l: 
>directory, but I can`t remember where.....

Sounds like you've been bitten by the infamous NULL bug.  This comes about
from two conditions:
	1) Lots of programs depend on location 0 containing 0 (ie, they
	   indirect through NULL and expect to get NULL back)
	2) Normally, location 0 contains 0, and all is well with the world.
	   However, when you install an A590, for some reason, location 0
	   gets written with some value besides 0.

	Bottom line is 1) + 2) = guru

Try writing a small C program (or assembler, if you know it) like this:

	#define NULL 0L
	main() { *NULL = NULL ; } 

And then run it in your Startup-Sequence before anything else.

-- 
Dave Schaumann | dave@cs.arizona.edu | Short .sig's rule!