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From: bochner@lange.harvard.EDU (Harry Bochner)
Newsgroups: comp.sys.mac.system
Subject: Bad Free Block Count?
Message-ID: <4266@husc6.harvard.edu>
Date: 26 Sep 90 18:14:04 GMT
Sender: news@husc6.harvard.edu
Reply-To: bochner@lange.harvard.EDU (Harry Bochner)
Organization: Aiken Computation Laboratory, Harvard University
Lines: 21

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 :-(
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 ...

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.

My questions:
1) Are any of these things checked by the disk check the system does when it
   comes back up after a crash? What does it do, actually?
2) What utilities are available for tracking down and fixing problems
like this?
   Does anything allow disk surgery on HFS volumes the way FEDIT did for MFS?
3) How do I get my 1.2 Meg back, short of reinitializing the disk?

Harry Bochner
bochner@das.harvard.edu