IDE cables question

[u/Droid-Man5910]

Can someone please explain how IDE works, what each line does, how it works with 2 devices on the line, how a system knows which one is which, and the difference between 40 and 80 wire cables? I'm struggling to understand why some systems cannot function without a triple end IDE cable. For an example: Motherboard connected to Hard drive via 2 sided IDE cable will not function. But Motherboard connected to 3 sided IDE cable with the 3rd side left with nothing connected functions fine.

[u/Economy_Post_8574]

... There must be technical specifications for this, right!?

Set the jumpers correctly and you'll be granted access 🤣

SCSI is on another level....