[HM] Re: Freezes & glitches

[Alex]

On Wednesday, Feb 18, 2004, at 22:34 Canada/Eastern, Bob K wrote:

> My problem seems to be fixed, with a run of my newly arrived
> Disk Warrior v3.0.1.   But, I tried among the first things the
> "test" user account, and also my problem started in Jaguar,
> and the Archive & Install installation of Panther didn't help
> either.  The freeze happened even with starting up from the
> Panther Installation CD.

Here's a working hypothesis (or perhaps just a speculation, at this 
stage), based on several user reports.

(1) Apple has been using lately some marginal RAM chips (especially 
Samsung).

(2) Mac OS X is particularly sensitive to bad or marginal RAM. RAM 
functioning at the limit of the specs may cause occasional, and 
apparently random, problems.

(3) This issue is much more noticeable in DP Macs, because SMP imposes 
tighter RAM requirements.

(4) RAM problems lead to file system corruption. Fsck at startup should 
catch and repair such corruption, but that doesn't always happen (and 
fsck only runs if the dirty bit is set).

(5) File system corruption snowballs to more and more problems. 
Eventually, the user employs a utility such as DiskWarrior to repair 
the file system, but the cycle will begin again.

f