>Hard disk drives seem to last much longer if they're left running
>continously. I'd reccomend disabling "power saving" modes on HDD
>unless power consumption is critical (e.g. a notebook computer when
>running on internal power). However, HDDs often fail if they've been
>running continously for years, then switched off & left off long
>enough to cool right down. I think the heads get "glued" to the
>platters. The best advice for HDDs which must be turned off is to
>turn off, wait for 2 mins, turn on, wait for 10 mins, turn off, wait
>for 10 mins, turn on, wait for 2 mins & finally turn off. The idea is
>to dissipate the "glue" which accumulates with constant use.
For what it's worth...
I've heard that referred to as "stiction" :) There's a decent enough
solution to the problem of "stuck" drive heads, but you really should be
absolutely sure that's what the problem is...
Drives have a "landing zone" or parking area where the heads will move to
when it's powered down. There's no data on that part of the track, so if
your heads do get stuck there when it's turned off, there's something you
can try...
Again, be sure that's really what the problem is before trying this... :)
But, in short, with the drive powered on and making the "hey, my heads are
stuck!" noise, you gently rap the drive on a hard surface. Rap it harder
and harder until finally you hear the heads moving about normally. Usually,
the head will unstick itself and as long as the head wasn't actually
damaged, you may have just enough time to get your data backed up pronto.
Jeremy and I used to do that alot on those first generation IDE drives
(which seemed to have this problem much more often) back when we were
computer techs... It sounds funny, I know, but it worked great most of the
time.
For what it's worth, modern drives rarely have this problem. Even the
10,000 RPM drives which get QUITE hot during use have good landing zone
areas where the heads aren't likely to come into contact with the hot
platters.
>Power supply units seem to have a life which is governed primarily by
>the number of times they're turned on & off. I've never heard of one
>failing in service whilst being fed a clean mains supply, but, given
>a mains glitch, it's common to have to replace a proportion of PSUs.
>(Like light bulbs, they seem to fail at the instant power is applied)
For power supplies, having a decent UPS or even just a good line conditioner
is a MUST when you want to prolong it's life. Anyone who cared to could
hook an scope to a power line (make sure the scope is protected from
overvoltage! :) and if it's a nice digital scope, you can see the surges and
sags that happen *all the time*.
Of course, not many folks have digital scopes... But a decent UPS does it's
own logging...the APC Smart-UPS for instance. It'll keep track of the peaks
and valleys through the day and it really is amazing what your poor little
power supply has to deal with all the time. Sags can be just as damaging to
your supply as a spike, by the way.
>I find the commonest failure in PC systems is _cooling fans_. Like
>HDDs it seems to be the case that the bearing will "glue up" if an
>always-running fan is switched off & left to cool right off.
>Sometimes this makes them very noisy for a few minutes when power is
>restored, sometimes they just plain fail. Broken cooling fans are
>definitely very bad for the reliability of PC systems!
I'll second that. Good servers (compaq servers for instance) monitor temps
at key points and actually have redundant, hot swappable cooling fans.
Gotta love that stuff.
Aaron
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