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?

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.

a.