27 Nov
2008
27 Nov
'08
12:37 p.m.
Subject: Re: IDE <-> MFM
From: ard at p850ug1.demon.co.uk (Tony Duell)
Date: Thu, 27 Nov 2008 19:35:41 +0000 (GMT)
To: cctalk at classiccmp.org
If I needed to go from IDE to MFM I'd go to my junk box and pull out a
WD1003 (or one of the smaller versions) and fake the interface of
IDE to ISA16. The two are so close its only the matter of the
IO address lines to resolve them down to CS1 and CS2. Command wise
the 1003 was the prototype for IDE command set.
Allison
On Wed, 26 Nov 2008, Jules Richardson wrote:
OK, but IDE bus interface cards do exist. Meaning cards that link ISA
(or whatever) bus to an IDE drive. For ISA, it's little more than an
address decoder and buffers (I happen to be using one in this PC).
Fred Cisin wrote:
That doesn't make sense. IDE stands for Integrated Drive Electronics,
which means that the controller is located on the drive. Therefore IDE
controller cards don't exist, and you can't bride IDE to an ST-412 IIRC, my Compaq "Portable 286" (NOT the
"Portable 2")
had a pre-standardization ISA IDE "controller" that cabled to a bridge
board on an MFM drive
Isn't that the other way around, though: IDE controller -> bridge -> MFM
drive? The previous poster's saying* they're doing this the other way interface type drive.
Sure you can. Make a PCB containing a WD1003-like disk controller. On one
side, have ST412 connectors to conencto to that sort of drive. On the
other, have an IDE interface -- data lines, 3 address lines, etc. In
other words the original PC/AT disk controller board minus the floppy
controller and minus most of the address decoder. Linked to the IDE bus
interface I mentioned just now, you have a complete ST412 hard disk
controller system. And the seond part of it could reasonably be called an
IDE (host interface) to ST412 (drive interface) bridge board.
-tony