I was recently creating a dump of a magneto-optical disc and suddenly the MO drive started seeking like crazy. I thought, uh-oh, it's died. Then I noticed the NeXT cube clock read 4am. So I switched it off and I hope the drive will be OK.
On NextStep 3.3, the default /etc/crontab runs /usr/adm/daily every day at 4am which runs a "find / ...", which causes a lot of MO drive seeking (on other versions of NextStep, the time may be different, e.g., on 2.0 the default crontab seems to have it set at 2am). I'm not sure how much such seeking contributes to potential overheating and early death of an MO drive, but it seems that it may be best not to run dump jobs when cron is about to run /usr/adm/daily.
Or you could kill the "find / ..." process, of course.
A sad day for me... one of my rebuilt drives just failed after dumping around 190 MO disks. I guess it was to be expected, but sad nonetheless.
Now the good news... it turned out to be a dry solder joint on the motor. The drive is alive and well again.