[X4U] Screen freezes in OS X

[Jim Robertson]

I reported here a few weeks ago that I'd suffered a "screen freeze" in OS X
10.4.6 on my dual G5 1.8 GHz PowerMac. A few diagnostic suggestions were
offered. One was to see whether the machine was "really" locked up by
setting the menubar clock to increment its display each second. I've had two
more such freezes, and on both occasions, the clock display stopped
incrementing. The screen really isn't frozen, however, because it still
shows cursor position when I move the mouse.

When the screen and keyboard are frozen, the machine is not frozen. I can
log into it as a server from my MacBook Pro, read files from its hard drives
and write files to its hard drives, but I cannot do anything from the
machine's own keyboard. If I press the "sleep" LED on my Apple LCD display,
the LED dims but doesn't extinguish, and the machine doesn't sleep. If I
hold down that LED on the monitor, the machine will power off. On reboot,
the recovered files folder in the trash holds six files whose names all
start with "dftmp" (five of the six are named dftmpGELNNHAM with some
subsequent lower case k and other characters, the sixth dftmpCPEMKHAM, also
followed by a string of k and other lower case characters. The Recovered
Files folder in the trash also contains a SENDMAIL folder, which is empty.

Another suggestion was to open Activity Monitor and the Console to see if
anything unusual occurred (spikes in processor usage or RAM usage, for
example). I have those logs, and just a few minutes ago another freeze
occurred. I'm not capable of interpreting the logs. Rebooting after this
most recent freeze, the CPU usage bar graph now shows the two processors
alternating in rhythmic spikes of CPU usage by System (from a low of 5% to a
high of more than 30%, the spikes being about 18 seconds apart per processor
(so total System CPU usage peaks at 30% or therabouts every 9 seconds). My
sense is that this is not normal, and my MacBook Pro certainly doesn't do
this. At the moment, the only things I'm doing on the machine are typing
this message, downloading in Thoth, and watching the logs and Activity
Monitor.



Is anyone interested in looking at my console logs? Is there someone else I
should report this to? It's not something I can show to my local Genius,
because this has happened only 3 times in a month. On each occasion, the
freeze occurred when I was closing windows or changing focus from one window
to another, but I cannot reproduce the freeze at will.

Thanks so much,

Jim Robertson
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