I now officially christen this the "old guy thread of the day".
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.
If I remember correctly, "PR#6" was basically just a command that executed the code at $c600. Each peripheral card had a 256-byte address space which was mapped into $cx00 where x was the slot number. Slot 6 was the standard slot for the disk controller -- it may even have been wired in, in later machines. So "PR#6" basically executed the firmware boot loader for the floppy drive.
What I found weird was that I remembered the command, but not the technology it came from or exactly how I used it. So I'm Googling around trying to figure out when and why it was important. For some reason I remembered it as "Print #6".
Old age and forgetfulness is going to be really strange for a whole generation of computer nerds. So many different technologies, commands, and paradigms all jumbled up.
See, my first computer was a Tandy 1000 and it just ran off of floppies and RAM. No hard drive. My mind was blown when we upgraded to a Windows 3.1 system that not only had a hard drive, but also a 3.5" floppy drive. WHOA, SMALLER DISKS.
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.