5-1/4' drive on modern PC

From: Tony Duell <ard_at_p850ug1.demon.co.uk>
Date: Fri Dec 10 18:17:50 2004

>
> There was an attempt to "simplify" connection of multiple floppy drives
> (meaning TWO) at one time by adding a "twist" to the cable-- some
> conductors in the ribbon are cut out and reversed, which is a sort of
> "cable select" for floppy drives.
>
> I seem to recall in this case that one would jumper both drives as drive A
> in such a case, or as DS0.

I tought it was actually DS1.

>
> Stupid idea. Use a straight thru floppy cable and jumper one for DS0 and
> one for DS1. We get it.

The 'IBM twist' also gave you sparate motor-on lines for the 2 drives,
and the original controllers (XT and AT) certainly controlled them
separately. You can't normally get away with an untwisted cable, no
matter how you jumper the drives.

-tony
Received on Fri Dec 10 2004 - 18:17:50 GMT