May 22nd, 2006

"Fan failure is critical" nonsense

People seem to be scared when their fan fails and/or when their CPU temperature reaches 80C. Don't be, it is okay:

a) ACPI specifies that hardware should protect itself from damage. If CPU temperature reaches 95C or so, machine is shut down _by hardware_. If operating system is able to interfere with that (it should not be), your hardware was trash in the first place. This failsafe actually tends to work on most machines. I tested it multiple times by sticking piece of paper into the fan, then loading CPU with kernel compilations while machine was covered in bad. And machines actually tend to survive that.

a1) okay... CPUs survive that, but watch your harddrive temperature. If it happens once in a while, it is probably okay, but running machine in this state for 8 hours is a bad idea. I did it few times and harddrive did develop some bad sectors (old HP omnibook).

b) CPUs are specified up-to 95/100C in common cases. Look at the datasheet. It does shorten the life of the CPU... but your CPU is still specified to run at 95C for three years in a row. So you can safely ignore that.

Now... I had some problems with overheats... but I actually used machine with failed fan for a year+. And then I had a funny failure where two notebooks were sitting on one another, and the top one overheated (compaq evo), deforming the case of hp 5000nx below it. Fortunately the case returned to normal after cooldown.

So... don't be scared. Ouch, you can sometimes get to a state where machine will not boot after bad overheat. BIOS actually sees too high temperature and refuses to let it power up. Let it cool for 15 minutes then try again. (I've seen this too few times.)

Olympus c-765 user interface... horrible. I thought my camera had broken flash. Not so, I just selected "hispeed multi" mode (which makes camera react at useful speed), unfortunately which disables flash in pretty un-obvious way.

Olympus, could you do some user testing perhaps?