Introduction

A system which is required to deliver it's service in a timely fashion is called a Real Time System. An aircraft flight control system is an example of such a system. Correctness of such systems not only depend on the result produced but also on the time at which results are produced. In such systems the meeting of timing constraints thus becomes a major deisgn issue.

General purpose operating systems, like linux are not suitable for handling such real time systems because of their inability to guarantee execution and response times of tasks. They also have some undesirable features, like large and unbounded interrupt latency, huge context switch and system call overheads and lack of support for specifying timing constraints etc., which make them unsuitable for real time applications. Thus there is need for a real time kernel.