with the twisted cable you _can't_ install a wrong
drive
as add on, and you _don't_ need to check any jumper or
what ever (supposed the drive is factory jumpered to #1)
I recently helped a friend with a floppy problem. His broke so
he bought a new one from CompUSA. It didn't work. Two other
geeks looked at it before me with no success. I tried to read
a floppy, noticed the errors and lights, etc. then pulled the drive,
found the slide switch on the side and changed it from 0 to 1.
Don't assume drives are set to unit 1 at the factory.
-ethan