DESIGN OF A REAL-TIME MULTI-TASKING KERNEL USING MESSAGE PASSING

Abstract

Multi-tasking executives attempt to increase CPU utilization by always having something for the CPU to exe-cute. This requires several tasks to reside in memory at the same time. In this.dissertation, an operating system kernel has been designed. It can be characterized as a real- time multi-tasking kernel, which provides inter-task communication by message passing and employs priority pre-emption as its scheduling strategy. The said kernel, also provides a facility to create and initialize tasks as also to add or delete any task without affecting the others. The kernel procedures have been written with the LSI-11 processor in mind. The host operating system could be RT-11 which is a single user system. The language chosen is Pascal keeping in mind the usual advantages of a higher level language over lower level languages. The programs also include assembly codes, where necessary to allow direct interface with the hardware. A test system consisting of three typical user tasks is also designed for testing the kernel procedures.