Re: hard drive guts questions.


"Jay Christnach" <jay.christnach@xxxxxxxxxxxxxxxx> wrote in message
news:446cf235@xxxxxxxxxxxxx
"J" <nospamplease> wrote:

Newbie questions way over my head, but here goes...

1) I have a newer sata drive dissassembled.

if you opened the housing which contains the disk plates, keep it as a
decoration, it will most probably never work again (dust)


Yeah, I know. It was most likely dead - I had already done data recovery on
it after it crashed with frequent clicking / boot sector errors. That's
alright. I opened _this_ one because its the newest 'disposable' drive I
had laying around. If I had opened an older one, It wouldn't tell me
anything about newer drive manufacturing. I specifically opened it to see
if there were any chips in the housing.

The outside pcb controller
has a contact interface with an internal printed circuit cable leading to
the
actuator - about 20 contacts.. Mounted on the cable attached to the
actuator body is a small chip. the printed circuit cable has a couple
wires which head off to the actuator's voice coil, but the rest of the
fine traces enter this chip, and the other side of the chip has traces
leading out to
the r/w heads (16 traces - 4 to each head). What is this chip?

It is the amplifier(s), the signal from the heads is so weak that the
amplifier has to be as close as possible to the heads to minimize noise.


*smacks self*. of course! That's awesome. So I could, theoretically, if I
wasn't a dumbarse, build a usb interface with ADDA converters and controlers
and such which managed the drive motors and heads. It's obvious to me now -
the chip had some extra traces to it for power... and two other mini surace
mount components.



2) What kind of hardware would it take to measure and graph the voltages
present on the printed circuit cable's outter interface while issuing
simple
dd linux commands? Could I put it together with on a usb/pic chip
platform?

Best would be to use the hardware on the outer pcb which was designed for
that task. The signal you get on the leads to the coils has to be
demodulated, decoded etc.

And the upshot lies here. Companies sell devices for data recovery for 30
to 50 thousand dollars. vogon has a component which supposedly breaks the
ata3 passwords.



3) The motor control seems to have 4 contacts. Are these 2 for power
and
2 for monitoring?

see stepper motor

right... makes sense, though I never immagined a steppermotor at 10,000
rpms.




4) 4 traces to each head: is this a write pair and a read pair?


don't know, but perhaps differential signal and two traces for ground
shield
or as you said 2 symetric signals read and write (don't think so)


incidentally, to each head, there's a pair printed 'in bold' and a pair
printed a little finer...

If you can point me to a very specific reference, that'd be great.
Thanks in advance,
-JB

Yes, would be very interesting! but really. Too expensive equipment needed
to do anything with the information.

I'm not specialized on that matter, but think about the transfer rates of
a
modern disk and you'll just say "wow, it worked and did cost me so few
that
I even dared to open it and screw it up"!

I'm a bit unclear on that last bit...
To address what I think you might mean,
1) I had no use for the drive anymore because I didn't trust it.
2) My theoretical device could afford to operate at slow speeds - it would
either image the drive or read the hidden ata password... the main idea is
to build a custom hd controller anyways...


kind greetings



.

Relevant Pages

  • Re: hard drive guts questions.
    ... has a contact interface with an internal printed circuit cable leading to ... actuator body is a small chip. ... fine traces enter this chip, and the other side of the chip has traces ... the r/w heads. ...
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  • Re: hard drive guts questions.
    ... actuator body is a small chip. ... fine traces enter this chip, and the other side of the chip has traces ... the r/w heads. ... or as you said 2 symetric signals read and write ...
    (sci.electronics)
  • hard drive guts questions.
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    (sci.electronics)
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