9 Dec
2004
9 Dec
'04
2:19 p.m.
Hans wrote:
Well, original ATA was nothing more than a straight
forward
adaption of the MFM controler -
It was a straightforward adaptation of the IBM *AT* MFM controller. The
standard IBM XT MFM controller was much different.
And the IBM AT MFM controller was basically an ISA-bus version of
the earlier WD task-file based controllers, which supported 8-bit
transfers only.
and that one was still good for 8 Bit access.
It's been so long since I've written any code for the original
IBM AT MFM controller that I don't recall whether it was actually
usable with 8-bit data register access or not (the control registers
are all only 8 bits). I don't have an AT Tech Ref handy to check.
Eric