At startup, Apple IIGS Desk Accessories are automatically installed by
ProDOS. It scans the sub-directory SYSTEM/DESK.ACCS on the startup disk for
any files of type $B8 (CDA) and installs them. A CDA is a classic desk
accessory, a menu of which can be accessed with Command-Control-Escape.
The format of a CDA is very similar to that of a regular application. The
main difference is the existence of a header that contains:
- a Pascal string that contains the name of the CDA
- a pointer to the entry point of the CDA code
- a pointer to the shutdown routine of the CDA code
More documentation on writing classic and new desk accessories will be found
in the chapter on the Desk Manager in the Apple IIGS Toolbox Reference Manual
in summer 1987.