IDE knowledge anyone?

[Maciej W. Rozycki]

On Wed, 30 Dec 2015, Oliver Lehmann wrote:

> Command 91h did the trick. Issueing this once before any
> read/write commands makes the drive finally work!

 FYI, this is what ATA-2 has to say about this command:

"Note: Previous ATA specifications were unclear about the error conditions 
that this command may indicate.  Some implementations do not indicate any 
errors for this command even when the command fails.  However, most of 
these implementations do fail media access commands if a valid CHS 
translation is not in effect."

-- which is (the latter sentence, that is) obviously what you've been 
observing with your WD drive.

 Also:

"A device shall support the CHS translation described in words 1, 3 and 6 
of the IDENTIFY DEVICE information.  Support of other CHS translations is 
optional."

 FWIW, and good luck with your project!

  Maciej