Henry wrote:
Type 'PR#3' and hit Return. Done.
A bit of context:The apple II has 8 expansion slots for plugging in floppy disk controllers, interface cards, extra memory, CPU accelerators etc. On the original Apple II and the II+, they were all the same size and were numbered 0 to 7. Slot 0 was reserved for the "Language Card" or 16K card which expanded a 48K machine to 64K RAM.
The Apple IIe has 64K RAM built into the motherboard, so the old slot 0 was obsolete and got removed. A new, longer slot was added called the AUX slot, into which you can plug an 80 col/64K card (like yours), or a video controller for an RGB monitor (+80 col/64K), or a Z-80 coprocessor (+80 col/64K), or a RAMWorks card with up to 512K, or 1MB, or even 3MB depending on the version. All of these cards provided 80 column capability + at least 64K RAM.
In Applesoft BASIC, the PR#n command means "redirect output to slot n" ... so if you have a printer card in slot 1, typing PR#1 will send output characters to the printer instead of the screen. Typing PR#0 is a special case, it means "redirect output to the screen", not actually slot 0.
Ditto for IN#n, it redirects input from the keyboard to the device in slot n, and IN#0 returns input to the built-in keyboard.
In the earlier days of Apple II, an 80-column video card was an expensive addition, and was normally plugged into slot#3. When Apple designed the IIe, they added circuitry to the motherboard to support 80 column video (if you had the necessary extra RAM in a card in the AUX slot). For software compatibility, they hijacked slot #3, so typing PR#3 (or IN#3) activates the built-in 80 column display circuitry. We still have a slot 3 in the IIe, but its usefulness is restricted (i.e. the variety of cards that will work in it correctly is limited).
When you get a floppy disk drive, you will boot the disk in the drive by typing PR#6 (or IN#6, same effect) assuming your disk controller card is in slot 6. This will also happen automatically when you switch on your Apple.
Martin