On 12/11/2015 01:26 PM, Oliver Lehmann wrote:
  I now tried something different. I issued a
"format track command"
 and sent 512 bytes afterwards as described in the ata spec. The drive
 does not respond with an error, and when I read the sector buffer
 right afterwards, it contains the exact data I transfered after I
 issued the format track command. 
 Okay, this is not getting results.  I believe that a long way back
 in the thread that you said that only one drive make+model exhibited
 this issue--other drives worked fine.
 Right now, I can't find the post where you specified the drive.  Who
 knows--I might have one. 
Western Digital Caviar 31600 it is.
I'm waiting for a 32Port-LA (might take up to a month). When it is there
I'll continue debugging that issue and see what a MS-DOS does different
 from what I do.