Wild-hair floppy drive question

Randy McLaughlin cctalk at randy482.com
Sun Jun 12 14:51:12 CDT 2005

From: "Tony Duell" <ard at p850ug1.demon.co.uk>
Sent: Sunday, June 12, 2005 1:06 PM

>> > If that is the question the answer is yes.  (use one hole media aka 
>> > 720k).
>>    I have a few pounds of DSDD 3.5" media.
>>    What I think I *don't* have is a 3.5" drive that can be jumpered to ID 
>> 0.
> The drive select jumper just links one of the drive select pins on the
> interface connector to the appropriate internal signal. So if your drive
> doesn't have jumpers, all you need to do is make up a cable between the
> controller and the drive that (in this case) takes drive select 0 from
> the cotnroller to whatever select pin (probably DS1) that the drive does
> respond to. And link all other signals straight-through.
> -tony

By "twisting" three wires:

10 - DS0
11 - GND
12 - DS1

you get what you want.

This is how IBM MFM drives had their twist done versus the floppy that 
twisted more lines to twist into it the motor on line.

Please note you CAN NOT use any PC twisted cable for a standard floppy cable 
but it is easy to "un-twist" part of a PC cable to use as a standard floppy 
cable for a lot less $ than buying the components to build your own.


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