Archived from groups: comp.sys.laptops (
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> powered on all day every day. In the power settings, should I set the drive
> to turn off after a period of time, or is it better for the drive to stay
> constantly spinning whilst the laptop is on?
Anyone who gives you a simple answer to this is, to put it bluntly,
foolish. Until a few months ago, I worked as lead engineer at a company
that made appliances containing 2.5" IDE hard drives. We were
experiencing a large number of field failures, so I went through all the
information I could find trying to work out "the" answer (mainly so that
we could work out the right warranty period to offer). From researching
all the datasheets, it's clear that there is no simple heuristic you can
use to answer this question, because there are several different
"lifetimes" built into the drive, viz (typically):
1. An overall powerup lifetime, assuming you power it up once and run it
until it dies. This reflects the lifespan of various electronic
components - mostly electrolytic caps, probably - at anticipated drive
operating temperatures. You can't affect this with Windows power
management settings.
2. A spindle powerup lifetime, assuming you spin it up once and run it
until it seizes. This reflects the lifespan of the motor, bearings and
the drive transistors powering the spindle motor. This is the lifespan
you eat LESS rapidly when you set aggressive power management options in
Windows.
3. A spinup/spindown cycle lifetime. This indicates how many times the
drive is expected to survive going into "low power" mode (turning off
the spindle motor while leaving the rest of the electronics powered).
This is the lifespan you eat MORE rapidly when you set aggressive power
management options in Windows.
4. A head load/unload lifetime. This reflects how many times you can
expect the unload mechanism to work properly, and the probability of a
head crash during load.
5. A power-cycle lifetime. This indicates how many times the drive is
expected to survive the stress of a cold powerup operation. You eat this
number every time you switch the laptop off and on.
The problem is, it is EXTREMELY difficult to look at all these numbers
(and there are usually others as well) and decide what exactly are the
best settings to extend the overall drive life - partly because the
"right" choice depends on how you intend to use your laptop *today*. If
you're going to spend 3 hours watching a DVD, then you'll be best off to
set a fairly aggressive spindown timeout, so that you avoid eating into
lifespan #2 above. Tomorrow, you might be working on a word processing
document, and saving every five minutes. In that case, you'd be better
off leaving the drive spinning, because 8 hours of one spinup/down per 5
minutes will eat a huge chunk of lifespan #3.
Moreover, the details are specific to the manufacturer and series (if
not individual model) of drive.
The manufacturer will combine all of these lifetimes to obtain the MTBF
(this is the number you usually see quoted as the "lifetime" of the
drive). The datasheet usually says what the assumptions were built into
that number. Typically, it is an artificial test usage pattern involving
a couple of spinup cycles every 24 hours, a certain number of sector
read/write ops per hour, and a certain number of powered-down hours.
The bottom line is that consumer-grade 2.5" IDE drives are not designed
for 100% duty cycle operation, and, like all hard drives, you shouldn't
rely on them for long-term storage.
Avoid shocks. Avoid using the drive in conditions of reduced air
pressure or increased humidity. Strenuously avoid tobacco smoke. Use the
drive in a manner that gives you acceptable performance and battery
life, in accordance with your typical usage patterns. Install additional
RAM to reduce the frequency with which the OS pages out data to disk.
Back up all important files regularly.
PS: Three years is good going. Although drives DO frequently last
longer, I would say 15-24 months is a good lifespan for a 2.5" drive
that sees heavy usage.
/phr.cx@NOSPAM.invalid> wrote:
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