2 Feb
2006
2 Feb
'06
1:48 p.m.
On 2/2/2006 at 9:19 PM ard at p850ug1.demon.co.uk wrote:
ST506 is a low-level, raw, interface. What you see on
the interface
connectoer is essentially the pulse stream to/from the head. It's up to
the cotnroller to turn that into the user data bytes/words.
A small nit--and an itch when I hear folks talking about the "ST506
interface" on a PC.
I don't think a stock PC ever talked to an ST506 for the simple reason that
the ST506 lacks buffered seek. AFAIK, every PC controller shipped with
BIOS that assumed buffered seek. You could reprogram most (but not all)
controllers to deliver the timed(3 msec?) seek pulses that the 506
required, but it wasn't stock.
We should really be talking about the "ST412 Interface", no?
I think the original poster was talking about the software compatibility.
While an IDE drive will respond to commands intended for an AT-style
(WD1003?) controller, such is not the case for the old XT controller, which
is close, but still a different animal.
However, if we're talking 8 bit PCs, it doesn't really matter too much, as
the INT 13 interface is carried on the controller's BIOS extension
ROM--which is what you need with an XT-class system.
Cheers,
Chuck