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From: geoff@desint.UUCP (Geoff Kuenning)
Newsgroups: net.unix-wizards
Subject: Re: "bitrot" on magnetic media: is there such a thing?
Message-ID: <247@desint.UUCP>
Date: Sat, 16-Aug-86 15:55:31 EDT
Article-I.D.: desint.247
Posted: Sat Aug 16 15:55:31 1986
Date-Received: Fri, 22-Aug-86 21:03:36 EDT
References: <826@PUCC.BITNET> <217@c3pe.UUCP> <1978@sdcsvax.UUCP>
Reply-To: geoff@desint.UUCP (Geoff Kuenning)
Organization: SAH Consulting, Manhattan Beach, CA
Lines: 22
Summary: Caveat Reader

In article <1978@sdcsvax.UUCP> jc@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