A multi-tasking executive

Abstract

This thesis describes the design and implementation of a real-time multi-tasking priority-driven executive, FOX. The name stands for "a East ObJect oriented executive. FOX permits the micro-computer user to enjoy the multi-tasking capabilities of the high performance machines like minicomputers. FOX tries to unify the concept of multi-tasking and team study of projects. FOX uses the concept of exchange for inter task communication and synchronization. For interrupts, FOX uses special exchanges called flags. There is no limit on the number of tasks and number of exchanges that can be created under FOX. There are 16 flags managed by FOX. Eigth of these flags are assigned to eight external interrupt sources via an interrupt priority controller. The remaining eight can be used by the programmers for fast and easy event processing. Each task running under FOX has an eight bit priority level, which is used by the task dispacher. All task exchange and interrupt binding is done dynamicaly by FOX to ease the team study of projects of large code size.