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From: ebert@arisia.Xerox.COM (Robert Ebert)
Newsgroups: comp.sys.mac.misc
Subject: Re: Strange things are afoot on my Mac IIcx
Message-ID: <12254@arisia.Xerox.COM>
Date: 7 Sep 90 23:26:57 GMT
References: <2801@nosc.NOSC.MIL>
Reply-To: ebert@arisia.UUCP (Robert Ebert)
Organization: Xerox Sunnyvale System Software Unit
Lines: 43

In article <2801@nosc.NOSC.MIL> edmunds@gandalf.nosc.mil (Daniel G. Edmunds) writes:
>Well, I think my Mac IIcx has come down with a strange virus.
>
>I ran Dis 2.1 and it said that Finder Sounds had a corrupted data fork.
>So I removed it from the system folder and continued on.
>
[other error descriptions deleted]
>
>I have tried reinstalling the system (6.0.5), rebuilding the desktop, runnig
>with Finder on and Multifinder off and vice versa.
>
>Anything sound familiar to anyone?

Yep.  Really weird things like that were happening to me, too.  They went on
for months.  I would have problems with a particular file or program, and would
(eventually) give up and delete it and re-install it, at which time something
ELSE would start acting weird.  Perplexed me for months... until I got
MacTools deluxe and tried the disk optimizer.  It said the volume block map
was damaged.  So I ran a bunch of other utilities, including Disk First Aid,
and they all said the same thing, but none of them were able to repair the
problem or even tell me which files or blocks were affected.

I ended up re-formatting my hard disk.  [I know, re-initializing would have
been enough, but I wanted to install a later revision of the Rodime drivers,
and that required a re-formatting.]  I re-installed everything from backups
and things have been fine since.

If you don't have a backup set, you can make one off your current disk.  Only
one (or a few) files should be corrupted, and you can just delete those later.

Technically, what's happening is that the same disk block is being mapped to
more than one file.  So files get corrupted.  Nothing will change until you
delete one of the files that seems corrupted, or otherwise change which files
are affected by the block mis-management... but when you do, some totally
random (seeming) file will become corrupted.

Does anyone know of a good utility for discovering which files are mapped
to which blocks, or otherwise exploring the relationship of files to disk
blocks?  I remember doing this by hand in my Apple II days with DOS 3.3, but
I don't know enough about the Mac file system to do the same thing now (with
FEdit or whatever...)

			--Bob