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From: jimb@silvlis.com (Jim Budler)
Newsgroups: comp.sys.mac.system
Subject: Re: Bad Free Block Count?
Message-ID: <1990Sep29.063509.1585@silvlis.com>
Date: 29 Sep 90 06:35:09 GMT
References: <4266@husc6.harvard.edu>
Sender: usenet@silvlis.com (USENET news maint)
Reply-To: jimb@silvlis.com (Jim Budler)
Organization: Silvar-Lisco,Inc. Sunnyvale Ca.
Lines: 42

In article <4266@husc6.harvard.edu> bochner@lange.harvard.EDU (Harry Bochner) writes:
>After a crash last night, my hard disk came back up saying it had 2.3 Meg free,
>down from 3.5 Meg before the crash :-(
Ugh!
>A manual check didn't reveal where the space had gone, so I tried ShowSizes,
>a (fairly old) utility showing how much space is being used by each folder.
>IT tells there's 3.5 Meg free !! Hmmm ...
It's probably totalling all the files, and probably correct.
>
>My guess is that the disk is corrupted in one (or more) of the following ways:
>1) bad free block count in the Volume header.
>2) garbage in the block allocation bit map.
>3) corrupted Extents B-tree.

 
You're probably correct.
 
There are several utilities that are supposed to correct such things.

First you might try Disk First Aid. You should have a copy, it
comes with the System Software from Apple.

Of others:
I can only speak for Norton Utilities for the Macintosh.
I have a copy and love it. It checks and repairs (or attempts to)
this type of problem. I've used it on several machines, and have
found problems, been informed of the exact nature of the problem,
and prompted a request to repair.

The only reason I placed the caveat above is because I have one machine
on which it crashes during the attempt to repair. No fear, after the crash
the machine comes up with the problem still there, but no additional
damage done.

On that machine I am going to have to do a backup, format and restore.
I haven't had the time, the user is experiencing no problems.

jim

--
Jim Budler          jimb@silvlis.com       +1.408.991.6115
Silvar-Lisco, Inc. 703 E. Evelyn Ave. Sunnyvale, Ca. 94086