5-1/4' drive on modern PC

Fred Cisin cisin at xenosoft.com
Fri Dec 10 17:26:30 CST 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.

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.




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