cquirke (MVP Windows shell/user)

On Sat, 4 Aug 2007 12:24:06 -0400, "Richard Urban"

>You don't turn off a computer by using the power button. That is called an
>improper shutdown. You use the shutdown button/command in Vista (or any
>operating system). This initiates the proper shutdown sequence for that
>particular operating system/computer.

Actually, that can be YMMV. The old pre-ATX PSUs had a "real" power
switch that physically disconnected the mains with immediate effect,
which also helped isolate the PC from mains spikes, lightning etc.

But the "power" switch for ATX PSUs is a transient push-to-make switch
that asserts a control signal to the motherboard (assuming the
switch's lead is connected to the correct pins on the motherboard).

When pressed, this signal requests the system to power off. BIOS and
DOS will generally do so with immediate effect, but recent Windows
will trap the request and either do a proper shutdown, or
suspend/hibernate, depending on BIOS and/or OS settings.

However, if you hold down the ATX off button for several seconds, the
motherboard's circuitry kicks in and powers off (more accurately, goes
into a powered-off mode that still trickles keep-alive power to the
PC's innards) with immediate effect. This works even when the
motherboard has no CPU or RAM, BTW... it's a deep hardware thing.

There are two important take-homes here:
- unplug from mains if doing any open-case work
- unplug mains (and phone, LAN, peripherals) for storm protection

>Improper shutdowns can corrupt the hard drive.

True!

AutoChk will "fix" the file system corruption, but will do so with no
regard to your data. Much as a club bouncer would "help" a dancer
suffering a siezure by throwing them out of the club.



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I *am* a power user!
I have electricity bills to prove it!
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