4 points
I’m not 100% sure off the top of my head, but the end result is that the drive is set to A: rather than B: in Windows. Something to do with the pins on the motherboard specifying the drive order.
5 points
You are correct. Later drives sometimes had a cable select dip switch/pin or different ports on the motherboard.
1 point
Right the jumpers would be cable select, master , slave generally. You could use master and slave or cs but shouldn’t together. Not that you can’t but screwing up your jumpers was the easy way to be pulling you hair out for failure to boot to the right drive or failure to id in the right order.