9 Dec
2004
9 Dec
'04
4:08 p.m.
From: "Hans Franke"
<Hans.Franke(a)siemens.com>
Am 9 Dec 2004 11:46 meinte Eric Smith:
Hi
As I recall, the commands were 8 bit compatable
but the data wasn't since this was not to the
controller but to the storage buffer. I believe
that the newer drives are not even 8 bit compatable
for the commands.
Dwight
Steve Thatcher wrote:
> considering that the ATA-1 spec included 8 bit transfers from the
> harddrive, I don't understand why no IDE drives that supported ATA-1 would
> not work on a PC/XT (unless the DMA speed was the problem).
I wasn't aware that 8-bit was included in
ATA-1; I don't have a copy of
ATA-1 or ATA-2. Was the 8-bit support mandatory or optional? In any
case, it was certainly gone by ATA-3. I very much doubt that any ATA
drive manufactured in the last 15 years has 8-bit support.
Well, original ATA was nothing more than a straight forward
adaption of the MFM controler - and that one was still good
for 8 Bit access. Also, there was never (at least in the beginning)
a formal Standard, so as usual everything was possible ...
just remember all the problems of Master/Slave combinations
from different vendors.
Gruss
H.