Hello
A little premise is a must
I'm the chief of technical operations at Recupero Dati RAID FAsTec , based in Italy but servicing worldwide
and since we do also hard drive data recovery with (if necessary) clean room operations
I can explain the point of the initial question
First of all a WARNING
When there is something abnormal or not typical in the behavior of an hard drive , it is safer keep it turned off
Also a clean room specialist can't guess what is going on,
so unique wise action we do is to open the drive in clean room and inspect and check heads for abnormal bendings and platters surfaces and absence of dust
If everything is fine and we'll shaped, we then power on the drive and eventually continue with a diagnosis made with PC-3000 for SAS drives (or SATA for the SATA cases)
If you are in a condition that allows yourself to risk the data and you wanna experiment, when it comes the 0GB case
you can power on one healthy drive (if you have one identical) and compare the spin-up phase and in particular, after the spin-up, the recalibration sound
Unfortunately SAS drives (beware) won't click if heads are bad and so people will further damage the drive because in absence of such weird noise, they will think the drive is operational
they won't click but... They won't recalibrate.. so
no recalibration = bad heads
(and probably you have already disrupt the platters surfaces)
If recalibration sound is there and (luckily) we had the chance to compare the spin-up and recalibration with the one of a good drive,
and the drives sound identical (identical)
well, a 0GB is pretty often symptom of a firmware module corruption
Given that such corruption is again symptom of a drive that is wearing, with the aid of the special devices we can work with the firmware and fix the module
Then a cloning process will be needed because as said above the drive is going to die
and we mean cloning again with the aid of PC-3000 and it's propertary SW DataExtractor
To reply to a comment above: a 0GB drive is 0GB in the disk manager too, that is not a partition corruption
That is