[filmscanners] RE: HD failure [was RE: keeping the 16bit scans}

["Kapetanakis, Constantine" <KAPETAC@polaroid.com>]

I am not sure where people get the impression that by not switching
equipment "off" they will extend its life. For 99.9% of the time that is
false.
Equipment fails from either "random stresses","manufacturing defects" and
"wear-out". When any equipment is turned off is NOT subjected to any
external stresses, wear-out is pushed further out etc.
As a reliability engineer i have not run across a case where leaving
equipment "ON" improved its life.



-----Original Message-----
From: Bob Frost [mailto:bob@frost.name]
Sent: Tuesday, April 01, 2003 8:11 AM
To: KAPETAC@polaroid.com
Subject: [filmscanners] Re: HD failure [was RE: keeping the 16bit scans}


Mike,

Thanks for that info.

Like you, I have never used HD power management; that seems like asking for
trouble. But I do turn the computer off at night. From your figures of
40,000 HD startup cycles, that gives a mean life of 120 yrs if turned off
once a day. Good enough for me, and better than the MTBF.

I think the important thing that many people and computer manufacturers
don't consider is the "at 40 degrees C" that you mentioned. Many cases have
little or no cooling for the hard drives; others have the facility to add an
extra fan to cool the drives, but don't include it as standard. My current
box (a CoolerMaster) has two extra fans pulling cold air in straight over
the drives. My previous one had a moulding for a drive fan, so I added it.
With the bigger, faster drives that we are now using (with multiple drives
in close proximity in a box), this may be a serious factor in HD life.

Some people seem to be very unlucky with HD's, or they mistreat them. How
many times have I told people NOT to move their computers while they are on
and the drives spinning, or kick them when they are under the desk! I have
been using computers for many, many years and I've only had one HD fail!!
Famous last words, I suppose.

I suspect most HD's get thrown away long before they fail. I've just
'retired' an old 1GB drive that has been in and out of several boxes in it's
time, but it is not even big enough for a PS scratch disk or Win pagefile
these days!

Bob Frost.

----- Original Message -----
From: "Mike Brown" <mike.brown@mindblown.com>

In the intersts of keeping an interesting thread going here are some typical
reliability figures for hard drives:

Mean time Between Failure 300,000 hours (ie one failure every 34 years)

Start/stops (at 40 deg C) 40,000

On the basis of those figures I turned HD power management off on my PC. I
was finding the disks were getting turned off maybe twenty times a day,
which equates to one failure every 5 years or so.

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