Microcomputer systems are now very popular and suitable systems for small scaled applications whose software has been developed to be efficient and effective for individual cases. But it seems to be desirable to implement a microcomputer operating system which can provide the application system programmers with a more general effective programming tool.
A case study of a small scaled microcomputer operating system to discuss the software design philosophies with particular emphasis on user multi-tasking is used in this paper.
JSYS, a small scaled microcomputer multi-tasking operating system is designed and implemented under the purpose of providing the user with multi-tasking facility and a simple file system. It is also discussed how the currently general software axioms of modularity and modifiability can be used to produce a software system that meets not so small demands of user level reduction of the response time by the technique of user level I/O overlapping simultaneous operation of I/O devices with multi-tasking. The result of the discussion suggests that a more effective and speedy application system which has concurrent operations of several resources, can be designed more easily under the multi-tasking environment.
