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Old October 20th 04, 08:34 PM
w_tom
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Many answer this 'leave power on or turn it off' question
without doing step one - first learn the numbers. Too often,
the answer is simply based upon wild speculation about
stresses that don't really exist. Power cycling does affect
life expectancy. The numbers: A power switch is rated for
about 100,000 cycles. IOW that is power cycling the machine
seven times every day for ... 39 years. The lowest power
cycling number I had ever seen was on a IBM disk drive rated
for 40,000 cycles - which is power cycling seven times every
day for .... 15 years.

So yes, they did not lie when they said power cycling can
shorten the life of a computer. And then we apply the number
they forgot to learn. 15 and 39 years? Who cares? In
reality, power cycling has no adverse effect on properly
functioning hardware. Hours of operation is a more critical
numbers because excessive hours of operation are more often a
reason for system not powering on. After too many hours, the
weakened component fails on powerup.

Again, if numbers or manufacturer datasheet specs are not
provided, then the 'expert' is no expert. Instead he meets the
definition of 'junk scientist'. Junk scientists fear
numbers. Furthermore, if power on is so destructive to
computers, then power on is also destructive to TVs, radios,
and all other household appliances. Leave all TVs on 24/7 if
you believe those half truths about computer power on.

No, there is little debate among the experts. Turn the
machine off or put it to sleep when done. Myth purveyors
claiming to be experts never provide numbers. No numbers
means he is a junk scientist. The myth purveyor did not lie.
He simply deceived by forgetting to provide the numbers.

As for a plug-in protector, it can even contribute to damage
of the adjacent and powered off machine. It does not even
claim to provide protection from electrical transients that
typically damage computer hardware. This is another and
longer topic best answered elsewhere. Do you think that silly
little box adjacent to a computer will stop, block, or absorb
what miles of sky could not? The surge protector must do just
that to accomplish the protection that others claim. Even the
manufacturer does not claim to protect from the typically
destructive type of transient. Details on effective
protection that costs about $1 per protected appliance is
introduced in "Pull the wall plug or not?" in nz.comp on 7
Sept 2004 at
http://tinyurl.com/5ttwl

Turn the machine off or put it to sleep when done as the end
of the day. Is that monitor causing video card damage? Step
one - do both monitor and PC share the exact same wall
receptable and is that wall receptacle the three wire (safety
grounded) type? Is the wall receptacle safety ground pin
actually connected to safety ground? Yes, power on could
created trivial little transients that are normally grounded
by the safety ground. No safety ground on either machine or
separated safety grounds can result in a destructive ground
loop through low voltge video cables into video controller.

Ben Myers wrote:
There are two schools of thought regarding whether one should turn
off the power on a computer or not.

One school says that shutting down the computer entirely eliminates
wear and tear on moving parts, most notably hard disk drives and
cooling fans. But powering up a computer causes a momentary surge
of current which can wear out sensitive integrated circuits.

The other school says that keeping a computer powered up preserves
the electronic parts, which do not receive a slight power surge
every time the computer is powered up. If the operating system
AND the motherboard design together do a superb job of managing
standby mode, the hard drive spins down, the CPU generates less
heat, and the cooling fans either stop spinning or spin only
occasionally. Unfortunately, neither Microsoft nor motherboard
manufacturers have gotten standby mode to be 100% foolproof.
Not yet.

Certainly if one lives in an area of unreliable electric power,
powering down the computer is probably best. When electrical
current returns after a power outage, it sometimes surges and
burns out the power supply, occasionally taking other components
out if the surge is strong enough.

I've been a member of the former school of thought ever since the
days of the original IBM PC. My reasoning is that the data on
the hard drive of my computer is the most valuable and most
difficult to replace (even with regular backups). If the computer
is powered down when not in use for extended periods of time (my
rule of thumb is 3 or 4 hours), and it is protected by a good
quality surge protector, then the hard disk will escape damage
from transient power surges and other unpleasant electrical
phenomena. EVERYTHING else in a computer can be replaced at
reasonable cost. The data on the hard disk cannot.

The choice is yours. I've tried to provide an objective view
of both sides of the argument... Ben Myers