Generally this system works fine, but what if you want to bypass the disk drive connected to slot 6 and start up from the disk drive connected to slot 5? What you do is change the startup slot from Scan, the standard setting, to slot 5 or any other slot containing the drive you want to start up from.
But what if your disk drives are connected to ports? From the computer's point of view, ports look just like slots with cards in them. A 5.25-inch drive connected to the disk drive port emulates a disk drive connected to a card in slot 6. A 3.5-inch drive connected to the disk drive port emulates a disk drive connected to a card in slot 5. (See Table A-1.) Just choose the slot that corresponds to the drive you want to start up from.
You'll also be offered the option of starting up from a RAM disk or a ROM disk. Starting up from a RAM disk means starting up from an application that you've copied into the memory on your Apple IIGS memory expansion card.
You should not select the RAM disk as your startup device unless you have a memory expansion card in the memory expansion slot and you've copied an application to the RAM disk. See the Apple IIGS Memory Expansion Card Owner's Guide for more information.
Starting up from a ROM disk means starting up from an application permanently stored on a memory expansion card. (Depending on what kind of memory expansion card you get, you may or may not have applications permanently stored on a ROM disk.) The manual that came with your memory expansion card will tell you more about starting up from a RAM disk and a ROM disk.
The printer and modem ports work a little differently than the other ports on the back panel. Whereas most of the ports are configured to interact with a particular type of device (a disk drive, a monitor, a joystick) in a particular way, the printer and modem ports are designed so you can change their configuration. They are general purpose serial ports.
Appendix A: The Control Panel Program