How do I extend the Palm OS? Whats a Hack? Whats HackMaster?
The Palm OS has a System Trap system that works much like Interrupts on MS-DOS systems. These are system services that process all the OS events, such as user entered a Graffiti character, system timer, power-off/on, etc. They also made a way so that an application can change how these system traps operate by changing the vector for the traps to point to user code that can modify or replace the default system behavoior. These extensions are generally knows as ‘Hacks’. For instance, one could code up a Hack to replace the standard Keyboard dialog with a new input method, or insert a procedure into the event-handling code in order to perform special actions at the entry of a certain Graffiti character, or even patch the text field routines to allow hyperlinking between applications. The potential uses are even wider than the system software itself. Unfortunately, there are some problems with implementation. Where in memory does one put the routine?
