5-1/4' drive on modern PC - test-drb@ccmp.vtda.org

10 Dec 2004

...
 From: "Fred Cisin"
&lt;cisin(a)xenosoft.com&gt;

  >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. 
Several manufacturers had problems with their field dealers, such as
Computerland, being unable to properly handle things as complex as
jumpers.

  >I seem to recall in this case that one would
jumper both drives as drive A
 >in such a case, or as DS0. 
In the case of IBM, with a twist, jumper both as DS1 (SECOND drive).
In the case of TRS80, with pins removed in connector cables, jumper all
drive positions on the drive.

  Stupid
idea. Use a straight thru floppy cable and jumper one for DS0 and
one for DS1. We get it.
If you intermingle the two drive select ideas you may have problems where
both or niether drives light up and niether can read.  ---snip---
 Hi
  As I recall, the two drives with the twist were actually
 DS0 and DS2 as seen by the controller. If using a straight
 cable, one had to skip DS1. 
On PC (5150), with straight cable, I used drives jumpered DS0 and DS1.
On PC (5150),  with twisted cable, I used drives jumpered DS1 and DS1.

Hi
 I stand corrected. Thanks Fred. I knew it was something like that.
Dwight