Back in my day, kid, we didn't have no stinking floppies for our PCs. All we had was cassette recorders, and we were happy to have 'em!
Reading this question took me down memory lane to doing a lot of PR#6. Couldn't remember if that command was for floppies or cassettes. Had to look it up. It was how we did I/O on the Apple II. As I remember, you changed the number (PR#3, PR#4, etc) based on the physical slot the peripheral was plugged into. This was back when dinosaurs roamed the earth and real men wore skirts.