[Cryptography] My ignorance and drive firmware hacking

[Peter Gutmann]

Jerry Leichter <leichter at lrw.com> writes:

>I'd heard - I don't recall the source, and I don't know if it's true - that
>modern disks and controllers are "bonded at the hip":  There is factory
>equipment that determines a variety of parameters relevant to a particular
>physical disk and records these on the controller board.  The firmware uses
>these parameters to correctly access the disk.

Depends on the drive type, for example some IBM drives (which shows the
vintage) stored servo information in the controller, but that was only a
passing thing.  Most drives (caveat: last time I looked) use self-servo track
writing where the drive controller handles everything internally and writes
the metadata (AGC preamble, servo info, positioning info, etc) onto the drive
at manufacture time.  In addition to the servo data though there may be extra
information stored in flash on the controller, so if a controller swap doesn't
work then you may need to swap the flash as well.  Finally, that may also not
work, so any one of the above three options is a possibility (thus my
"glossing over the details" comment in the original post, it's a YMMV
situation).

Peter.