Possible to speed up I/O subsystem of 5150?

From: Eric Smith <eric_at_brouhaha.com>
Date: Thu Dec 9 14:19:21 2004

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
Received on Thu Dec 09 2004 - 14:19:21 GMT