rbbb@RICE.EDU (David Chase) (08/20/86)
I believe the man from CDC told us to leave ours running whenever possible. After several years of continuous (heavy) use we did experience something like "bitrot" on one of our drives; whatever it really was, it was NOT gradual; in the space of a few days we went from our normal error rate (1-20/day) to unusable (10-20% of I/Os failing). We NEVER had bearing problems, not even once, in our Winchesters. In our removable packs, however, we had several bearing failures and a few head crashes. We blamed this on repeated cycling and contamination. It is also the case that running Winchesters are quite resistant to physical shock; when unloading one, we (the man from CDC and I) bashed a running drive on a running system so hard that the side panel fell off (actually, the new Winchester did all the bashing when it slid off the pallet). No errors at all. A Hyperdrive in a Macintosh was also observed to be running just fine after the table holding it up collapsed. (Does anyone know how strong those air bearings really are?) It is, however, probably a good idea to cycle a drive down and up maybe once a month if it performs any sort of a self-test on power-up. Our drives would slowly drift out of (electrical) spec, and our first symptom of a problem was usually failure to pass the self-test when they were powered up. David
geoff@desint.UUCP (Geoff Kuenning) (08/25/86)
Many thanks to you knowledgeable folks for answering my question.
Now my only problem is deciding whether to leave the system on all the
time to "protect" the winnies, or continue my current cycling on/off
behavior to extend the life of the power supply, CRT, and other
electronics. (No, that's not :-). Oh well, nobody ever said life was
going to be easy.
--
Geoff Kuenning
{hplabs,ihnp4}!trwrb!desint!geoffmangler@cit-vax.Caltech.Edu (System Mangler) (08/31/86)
In article <250@desint.UUCP>, geoff@desint.UUCP (Geoff Kuenning) writes: > Now my only problem is deciding whether to leave the system on all the > time [...] or continue my current cycling on/off behavior to extend the > life of the power supply, CRT, and other electronics. Cycling the power causes thermal expansion/contraction which eventually leads to fatigue failures. If you want to extend the life of the electronics, keep them cooler with better ventilation or fans. Don Speck speck@vlsi.caltech.edu seismo!cit-vax!speck