This study describes real-time kernel essential mechanisms
and deals with the implementation of a real-time multitasks executive.
To make more advantage of microprocessors in applications involving many
functions simultaneously, our real-time kernel provides a multiprogramming
environment in which many independent multitasking application programmes
may execute and provides facilities to manage efficiently the processes
(tasks) and communicate between them. These facilities are provided by
system calls that handle data structures namely tasks, semaphores, messages,
events flag, resources, mail-boxes, queues and interruptions. Present
kernel is preemptive and priorities assigned to tasks are dynamic, the
kernel manages up to 63 task levels (63 is the lowest priority level assigned
to the idle task). Round robin scheduling is not used here.