The disposition of this problem depends on whether you have a pre-1MB Apple
IIGS computer or a 1MB Apple IIGS computer:
Pre-1MB Apple IIGS Computer
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For older (pre-1MB Apple IIGS computers) you can, under ProDOS 16 and
GS/OS, intercept the interrupt created by the Control Panel access
keystroke. For these computers, you need to write an interrupt handler
that accepts the Control Panel interrupt and disposes of it.
Startup programs, or INITs, are discussed in "Apple IIGS ProDOS 16
Reference" (ISBN 0-201-17754-4), published by Addison-Wesley. Pages 52
through 57 deal with the issues of boot initialization and the SYSTEM.SETUP
subdirectory. Both issues are of importance to the creation of startup
programs.
Interrupts and interrupt handlers are discussed in several places
throughout the book. Use the index to review the issues connected with
interrupts.
One shortcoming when using a startup program with ProDOS 16 or GS/OS
concerns ProDOS 8 applications. When a ProDOS 8 application is executed,
ProDOS also is executed, and, in the process, the INITs of ProDOS 16 or
GS/OS are not active until ProDOS 16 or GS/OS is executed again.
1MB Apple IIGS Computer
-----------------------
The newer 1MB Apple IIGS computer has a jumper at W1 that disables the
Control Panel. W1 is a two-pin jumper located on the logic board near the
power supply.