Hard disk


Thread Starter

Curt Jeffreys


Could anyone give me their opinion/experience with hard disks in embedded applications, in particular, is it better to let the drive spin forever or should it spin down when not in use? How does this affect the expected life of the drive?


Curt Jeffreys
CW Industries
Lakewood, CO USA

Johan Bengtsson

I think that mostly depends on how often you plan to have it spin up again. My guess (take it as a guess) is that if you need it to spin up more often than twice a day it is better to have it spinning if you only are looking at the expected
life, if power is something to be concerned about you might want to spin down anyway. As far as I have heard spinning up and down a disk is doing quite some damage compared so several hours
constant spinning. Ask a disk manufacturer about it they probably have done these kinds of tests anyway.

/Johan Bengtsson

P&L, the Academy of Automation
Box 252, S-281 23 H{ssleholm SWEDEN
Tel: +46 451 49 460, Fax: +46 451 89 833
E-mail: [email protected]
Internet: http://www.pol.se/

Jim Hulsebus

I have been in the Disk Drive/Magnetic Memory business for many years and you concern is higly debatable. Whenever a disk drive is started from a stopped position, the heads are on the media and require a certain amount of windage before they are in the " flying position ". This obviously causes wear. If the disk drives runs constantly the heat generated will cause bearing, and other machanical parts to change their original shapes..and may not be able find their outer tracks. This is where the boot information is contained. .. There are pro's and con's to both questions and allot of debate inclusive.
I have seen a disk drive fail in multitude of ways from heat soak components to " Sticktion ", a scenario that the heads adhear to the platters, from not being run enough.
My rule of thumb is if I don't use the system for long periods, shut it down. If I plan on normal,everyday use of the system .Let it run.
My personal P.C. I start in the Morning and shutdown at the end of the day. The hard disk is 6 years old.

Jim Hulsebus, Design Engineer, Miltope Corp.

Peter Whalley

Hi Jim,

Interesting comments.

I have seen some suggestions that temperature is a significant factor in disk drive reliability. Perhaps you could comment on the importance (or otherwise) of providing cooling for disk drives (such as the fans in some removeable disk carriers), mounting of the disk drives for good air flow and selecting lower rotational speed units which (maybe) generate less heat. What steps can we take to maximise disk drive reliability.


Peter Whalley

Managing Director
Magenta Communications Pty Ltd
121 King Street,
Melbourne, VIC 3000

e-mail: [email protected]