"andy" wrote in message
...
Hi!
Could someone please explain why in the case of *mechanical* failure HD
becomes sometimes undetected by BIOS and/or the operating system (e.g. win
xp
or linux)?

Consider the options available to the HD designer. What do you want the
user to see during POST about a HD that knows itself that it can't possibly
work. The HD designer knows that many BIOSs have no ability to detect and
display a HD error status during POST. The BIOS may only be able to report
'there' or 'not there'. If you were the HD designer would you want the HD
to report 'there' during POST even when the HD itself really knew that it
wasn't there? How would you answer the query of a poster in this NG who
wanted to know why a HD reported 'there' during post but was not there for
all intents and purposes for any booting steps after POST?

Did the HD designer make the correct design choice in the first place which
would likely cause a competent user to try another HD and assume that the HD
was dead dead which in fact it is?

If it was an electronic failure then such behaviour would be obious, but
why
the same happens with some mechanical failures? When electronics is
working in
my opinion it still should be detected by bios and/or the system (win xp
or
linux), but often it is not.

What on earth for? Such would be highly misleading and a very poor design
choice.

I could recover about 80% of the data from my HDD (which apparently has a
mechanical failure - plates spin up and down, heads create bad noises) if
only
the disk could be seen by the system all the time.

Huh?

But often during copying of
the data heads hit with a loud sound so badly that sometimes even the
plates
stop rotating, and the disk then dissapears from the system.

Duh!

It is then very
difficult to make it detectable by the system again, sometimes the sytem
can
detect it but only after several minutes of copying it freezes and then
dissapears again.
Recently, I was unlucky, and even after several dozens of retries it's
still
undetectable by the system.

Could you please advice what to do to make the disk detectable by the
system
all the time?
What causes that it is not detectable although the failure is in mechanics
not
electronics?

The drive is DOA!

BTW, if someone has the same disk model (Quantum Fireball ST64A011),
please
let me know.