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Don Klipstein

In article ,
wrote:

On Wed, 28 Oct 2009 08:06:49 -0700, Smitty Two
wrote:

As far as the computer, those shouldn't be left on 24/7 anyway, for the
health and longevity of the machine. I confess to being baffled by how
that myth got created and so widely adopted.

It got started by an IBM study on MTBF on hard drives that found a
power off/on cycle was worth about 8 hours of running time.
Prior to that it was studies on light bulbs and fluorescent finding
similar results

At one time, starting a fluorescent took something like an hour or two
off its life. Now it's more like 5-10 minutes, though probably longer
if it's used with an old fashioned "glow switch" starter that blinks it
afew times before getting it started.

As for incandescents - I'd like a cite for any of those studies saying
what you say. Although incandescents often burn out during cold starts,
cold starts do surprisingly little damage to most incandescents. What
happens is that an aging filament becomes unable to survive a cold start a
little before it becomes unable to survive continuous operation. The
condition that makes an aging filament unable to survive a cold start is a
hot thin spot in the filament - which worsens during operation at a rate
that accelerates worse than exponentially.

- Don Klipstein )