That can be valuable in itself, but even more features are offered by the clock module. This module can either take as an input some external periodic event in the system that calls the Clock_doTick() API, or more commonly is configured to use a periodic heartbeat from the SYS/BIOS timer module. The clock module creates a software interrupt which gets posted by one of these inputs and provides a way in which any number of different functions can be configured to fire off, either as one shots or periodically.  In this way, SYS/BIOS makes it appear to the application that it has an almost unlimited number of timers at its disposal.