On Wednesday, November 15, 2017 at 7:17:34 AM UTC-7, J. P. Gilliver (John) wrote:
In message , Paul
writes:
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The twisted part, consists of four active signals.
Two for each drive. The twist swaps the signals, so
that one connector can have an A personality and the
other a B personality. (Just like a CS Cable Select method.)

Only two pair of signals with one pair of them being /motor_on, I disremember the other. So only two drives possible. /Drive_select? eg. 'I am shining my light at you.'

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I've always assumed it was that, and thought it was a clever solution
(admittedly, requiring unusual cable construction).

So presumably there is something like (_at the drive_):

01 - A
10 - B

(or vice versa).

Does that mean there is the _possibility_ of _four_ drives, using up the
00 and 11 options?

As above no, even though it used to be
00 - A
01 - B
10 - C
11 - D

Floppy drives were very expensive and little utility was gained after two and an overpowering need to settle the faster and much larger hard drive in as drive C and D led to the extinction of more than two floppy drives.

But some 5 1/4 floppy drives have jumpers for those higher numbers and ALL using the twisted cable method must be jumpered to be drive 2 or drive B or drive 1 in a zero based counting system. Replacement drives sold new for the last 20 years or so will have the jumpers missing but the block where they used to be soldered to be set for drive B while a few have no jumper block solder pad to hack on anymore at all.

You would have to rewrite the BIOS in order to enable a 2nd floppy on this 2005 Dell even though they are using the twisted cable for Drive A, the BIOS has no provisions for Drive B as a floppy.