Tuesday, August 03, 2004

OS X 10.3.4 intermittent system freezes (iTunes, others): VM and HFS issue

MacInTouch 8/3/04
Rohan Lloyd nailed down a widespread Mac OS X freezing problem [discussed in our iTunes reports], which is apparently a known Apple bug, and noted his workaround:

The 'iTunes Freeze' that some readers are experiencing (well described by Jim Pollock) sounds like a problem I have experienced that is not related to iTunes.

I recently started getting system freezes with the same symptoms (system would hang, iTunes would periodically play about 5 seconds, mouse would move but nothing else)

I reported the problem to Apple, they got me to get a kernel stack trace when it happened and confirmed that it was a known problem related to VM and HFS that they are working on.

It's got nothing to do with iTunes, it's just that iTunes has a realtime thread playing audio that periodically runs out of data and has to wait till a non realtime thread fills up the buffer from disk. (at least that's my guess at what's happening)

About the same time I downloaded and tried out hfsdebug. When I look at the Volume header of my root volume:

$ sudo hfsdebug -v -V /Volumes/Macintosh\ HD

I saw that it had 'serious inconsistencies'

kHFSVolumeInconsistent (volume has serious inconsistencies)

After a backup/re-format/restore over a week ago, I haven't had the problem again (fingers crossed).

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