Why mechanical failure causes HDD being undetectable by bios or OS ?

"andy" wrote in message
...

It's not a "feature". The mechanical noises and other symptoms you
describe
most likely result from a head crash, where the heads, which normally
float on
a very thin cushion of air, have contacted the disk surface and scraped
the
oxide off the disk, making it unreadable. If it can't be read, it won't
come
"ready" (as in "ready to use") and the BIOS won't detect it. Once the
heads

It doesn't make sense to me. Even if part of the surface is destroyed,
most of
it is not,

Nonsense. Once any part of the surface is destroyed then then rest dies
VERY soon thereafter.

On Fri, 03 Sep 2004 20:59:17 GMT, "Ron Reaugh" wrote:

But I could then recover 80% of my data, and now I can recover 0% of my
data.
Does it make sense for you now?

Perfect sense and no you couldn't recover 80% of your data.

Why?

a.

On Fri, 03 Sep 2004 21:03:42 GMT, "Ron Reaugh" wrote:

Nonsense. Once any part of the surface is destroyed then then rest dies
VERY soon thereafter.

It depends what you mean saying that.
When the disk was detectable always the same data was unavailable, therefore I
assume that if only the disk could be detectable then I could recover 80% of
the data.

a.

On Fri, 03 Sep 2004 21:01:16 GMT, "Ron Reaugh" wrote:

When the disk was detectable then about 20% of files could not be read.
This was not because bad sectors (the disk did not have any AFAIK), but
because of the mechanics failure (when it started to have the symptoms of
the
failure also 20% of data became unavailable).

No, now 100% is unavailable.

Only because the disk cannot be detected.

a.

"Ron Reaugh" wrote in message
"CJT" wrote in message ...
andy wrote:

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)?
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.
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. 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. 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?

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

andy


Maybe it stores part of its own software on the platters.

Most all current HDs do that.

Nope, "most all current HDs" probably do not.
My IBM DMVS does not and that drive is already ~5 years old.
Flashrom has become cheap enough to take all the firmware, not
just the bare minimum part to spin the drive up and load the rest.

"andy" wrote in message
...
On Fri, 03 Sep 2004 21:03:42 GMT, "Ron Reaugh"
wrote:

Nonsense. Once any part of the surface is destroyed then then rest dies
VERY soon thereafter.

It depends what you mean saying that.
When the disk was detectable always the same data was unavailable,
therefore I
assume that if only the disk could be detectable then I could recover 80%
of
the data.

No, the entire surface is covered with pixie dust.

On Fri, 03 Sep 2004 23:00:39 GMT, "Ron Reaugh" wrote:


"andy" wrote in message
.. .
On Fri, 03 Sep 2004 21:03:42 GMT, "Ron Reaugh"
wrote:

It depends what you mean saying that.
When the disk was detectable always the same data was unavailable,
therefore I
assume that if only the disk could be detectable then I could recover 80%
of
the data.

No, the entire surface is covered with pixie dust.

So what. The data could not be recovered not because of bad sectors (there
were none before failure, not sure whether there are any now - not possible to
test it), but because of the bad movements of the heads, and bad spinning of
the plates.

a.

On Sat, 04 Sep 2004 00:11:12 +0100, andy
wrote:

So what. The data could not be recovered not because of bad sectors (there
were none before failure, not sure whether there are any now - not possible to
test it), but because of the bad movements of the heads, and bad spinning of
the plates.

LOL, since you seem to be an expert at it, recover the data and
then you have proof!

Your drive is dead, the data is gone... move on, you're just
wasting time now.

"andy" wrote in message
...
On Fri, 03 Sep 2004 20:59:17 GMT, "Ron Reaugh"
wrote:

But I could then recover 80% of my data, and now I can recover 0% of my
data.
Does it make sense for you now?

Perfect sense and no you couldn't recover 80% of your data.

Why?


Soot.

On Fri, 03 Sep 2004 23:53:02 GMT, kony wrote:

On Sat, 04 Sep 2004 00:11:12 +0100, andy
wrote:

So what. The data could not be recovered not because of bad sectors (there
were none before failure, not sure whether there are any now - not possible to
test it), but because of the bad movements of the heads, and bad spinning of
the plates.

LOL, since you seem to be an expert at it, recover the data and
then you have proof!

I will if you only tell me how to make the disk visible in the system.

Your drive is dead, the data is gone... move on, you're just
wasting time now.

Most of the data (perhaps even all) is not gone - all plates (or most of the
plates) are not damaged, so the data are still on them and just wait to be
recovered. I will recover it if I buy another such disk model.

But in one thing you're right - I'm wasting my time talking to you. :/
Bye.

a.