here is an update on what i have learned about bad ram

(BTW: my guess is that the only connection between bad ram and a bad disk is that maybe damage to the VM swap file might get corrupt the open files on the disk -- but journaling is supposed to protect us from precisely that sort of proble, correct?).

i had a problem with my bad 1GB piece in a ppc mini .... and the author of the awesome new book "os/x internals" (he works at the google O/S) has some very specific info about how the boot process becomes aware of bad memory at startup (fotunately the firware & the kernel work together to partition off bad ram, so that you can keep working).


but strangely, sometimes these settings are lost from openfirmware & you have to keep re-booting until FINALLY the POST (power-on self test) catches the problem properly and hands it off to teh boot-loader to resolve correctly ....

another sign of this weird side-effect is that the volume settings for the start-up chimes are also lost from openfirmware (which is really annoying on the ppc mini; because for some reason the mute command only works on the system sounds not the startup/bootloader sounds .... so it is necessary to use a little utility called PSST to force the boot chime to always be off -- but this command doesnt always stick, just like the results from the POST disgnostics dont always stick in the PRAM either, leading the RAM problem mentioned above).

BTW: i could agree more with the owner of this thread: running the DIAGNOSTIC DISK is absolutely essential when you start seeing hardware problems (as well as making the obvious inspection of the logs and the 'About This Mac' system profiler info) ... NOTE: the Diagnostics tools are contained on their own hidden partition (disk utility will NOT show it!) on the startup disks - so it cant be copied into a bootable disk image (from an ipod, for example) -- which is really too bad!)