Re: 386 12.5

Philip Blundell (
Mon, 9 Jun 1997 12:00:04 +0100 (BST)

On Mon, 9 Jun 1997, Thomas Pornin wrote:

> > Anno Domini 9 Jun 97 at 10:51, Thomas Pornin wrote:
> > > well, but I do not understand why it should work: the disk is an IDE,
> > > 120 MB, plugged in a MFM controller; the bios supposes it is a 40 MB disk,
> >
> > This is impossible combination, IDE disk has single 40-pin flatcable
> > MFM-disks and controllers have 2 cables, 34-pin controlcable and 20-
> > pin datacable
> Strangely enough, the bios is definetly positive about his controller
> being a MFM/RLL one. Anyway, this would explain why the disk runs (if it

>From the software point of view, IDE looks just like MFM and RLL (it was
designed that way). So the BIOS doesn't need to care; if it's an older
one it may not even know that IDE exists.

IDE stands for Integrated Drive Electronics - the idea being that the
MFM/RLL controller logic was moved onto the drive as well.