Pascal, modula-2 and multi-tasking kernel implementation

This paper presents a comparison of Pascal and Modula-2 based on the implementation of the basic components of a multi-tasking kernel. The major issues involved in high-level language implementation of a stand-alone multi-tasking kernel on a microprocessor system are the transportation of the language support system and what may be termed software engineering considerations. The merits of Pascal and Modula-2 with respect to these issues are compared. Standard Pascal is a sequential language, and the development of the multi-tasking features of the kernal has to take place outside the scope of the language. The Modula-2 language (nucleus), however, allows the kernal to be built entirely using high-level constructs. Issues of language run-time support and portability are also covered. These topics and the high-level handling of interrupts have received little attention in the literature on Modula-2. The Modula-2 kernel also provides a possible implementation of the `MODULE processes¿¿.