Resurrecting up an old topic.
Looking at this Q&A thread -
"The pins are in fact "Drive Select A", "Drive Select B", "Motor Enable A", and "Motor Enable B". The twist swaps Drive Select A<->B (pins 14 and 12, respectively) and Motor Enable A<->B (pins 10 and 16, respectively). All are outputs on the floppy controller and inputs on the drives. The rest of the pins (read and write data, stepper motor control, head select, etc.) are bussed in the normal fashion, which is why the drive select pins are so critical. A drive has to ignore all input and produce no output when it's not selected"
Does anyone know why this doesn't work on our system? I mean the technical reason why. Was helping Falcor with hooking up a HxC and realized I've always just made a straight cable and haven't questioned why the twist part doesn't work.
Edit: Blame IBM changing the Shugart standard. https://www.seasip.i...C/floppies.html
They added multi-motor control which wasn't in the original Shugart standard.
"When IBM built their first PC, they didn't think the power supply was up to having all the drive motors running at once, so they designed a system with separate motor control for each drive. A twist in the cable between drives B and A means that each drive sees a different motor control signal. As a consequence of this, you can only have two drives on a cable, rather than four."