"bitrot" on magnetic media: is there such a thing?

[Geoff Kuenning]

In article <1978 at sdcsvax.UUCP> jc at sdcsvax.UUCP (John Cornelius) writes:

> The wisdom of leaving your winchester running, even if the system it is
> connected to is not running, cannot be too heavily stressed.  Winchesters are
> designed for a continuous operating environment, not a sporadic one.  There is
> a school of thought that being nice to your disk drive involves turning it off
> when it is not in use.  I recognize that this thinking has some intuitive
> basis but it is, alas, quite incorrect.

I wonder if John could give us some references to support this contention.
In particular, one of the failure modes I have seen in Winchesters is
bearing failure.  Bearing wear is directly related to on-time, not to
the number of startup/shutdown cycles.

Let's remember that a lot of Winchesters are spec'ed with MTBF's of
10,000 hours or less.  There are 8760 hours in a year, so if you leave
your Winchesters on 24 hours a day, you can expect the average one to
fail after about 14 months.
-- 

	Geoff Kuenning
	{hplabs,ihnp4}!trwrb!desint!geoff