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

From: andy
Date: 09/03/2004 7:22 AM Eastern Daylight Time
Message-id:

On Fri, 3 Sep 2004 11:24:48 +0200, "Joep" j o e p @ d i y d a t a r e c o v
e
r y . n l wrote:

"andy" wrote in message
. ..

*Sometimes* ... So, maybe it's the nature of the problem that prevents the
disk from being detected.

Failure to mechanics seems to be the problem causing the non-detection
problem.
Unfortunatelly the "sometimes" is now "nearly always".

How do you know? How did you come up with the 80%?

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).

You should try to clone it as long as you can see it. However, every read
may worsen the condition of the disk, in general it is advised to cease DIY
recovery attempts (if the data is important to you) when a disk is maing
unusual and scary noises.

Yes, it seems that the condition very quickly became much worse.

Your issue is a psychological one. You can not accept that there are
situations you can not resolve and have no control over. Apart from

How can I know that? If they designed it that way that it should not be
detectable when mechanics fails, then maybe also for the service purpose they
designed it also to be possible to disable that feature, making the disk
visible despite mechanical failure.
I hoped that someone knows how to disable that feature.

Why do you want to know?

If someone has such disk with bad electronics, but good mechanics, then I
could use the mechanics to recover my data. Just for one time recovery even
opening the disk in not sufficiently clean condition possibly could work.

a.



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
crash, it only gets worse. If you open it up, you'll probably find bare spots
on the disks where your data once was.
To repeat, it's not a "feature" that can be disabled. Your drive is dead. Trust
me, I've serviced computer disk drives of various kinds since long before PC's
existed, and I know how they fail.
Chris

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, why then not to detect the disk?

crash, it only gets worse. If you open it up, you'll probably find bare spots
on the disks where your data once was.

I opened it now (I don't care about the dust, since it's dead anyway), and the
surface of the first plate is in perfect condition, I can't see surfaces of
other plates, though.

To repeat, it's not a "feature" that can be disabled. Your drive is dead. Trust
me, I've serviced computer disk drives of various kinds since long before PC's
existed, and I know how they fail.

I know it's broken down, but still, this behaviour of the disk is mysterious.
If it was like you said, then the disk would be dead all the time, but as I
described before sometimes it was possbile to detect it despite this failure.

Someone designed it that way, but perhaps there are ways to come round it.

a.

"andy" wrote in message
...

Thanks for your reply.

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.

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.

Is there any way to disable that feature? (I mean to make the
malfunctioned
HDD visible to the system again?)

The drive is DOA!

Don't get DOA.

Dead On Arrival

"andy" wrote in message
...
On Fri, 3 Sep 2004 11:24:48 +0200, "Joep" j o e p @ d i y d a t a r e c o
v e
r y . n l wrote:

"andy" wrote in message
.. .

*Sometimes* ... So, maybe it's the nature of the problem that prevents
the
disk from being detected.

Failure to mechanics seems to be the problem causing the non-detection
problem.
Unfortunatelly the "sometimes" is now "nearly always".

How do you know? How did you come up with the 80%?

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.

You should try to clone it as long as you can see it. However, every read
may worsen the condition of the disk, in general it is advised to cease
DIY
recovery attempts (if the data is important to you) when a disk is maing
unusual and scary noises.

Yes, it seems that the condition very quickly became much worse.

Isn't that what I said.

"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.

"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.