Operating Systems: Concurrent and Distributed Software Design

24.8. Summary

The original UNIX design was small and comprehensible. Some of its features were dictated by the PDP-11 architecture with which it was closely associated in its early years. The assumption that UNIX will run on a uniprocessor permeated the design of the kernel, in particular leading to a non-preemptive model. If a design decision required a choice to be made between simplicity and efficiency, the former was chosen. In the next chapter we look at how some of the major deficiencies have been addressed in some of the most commonly used versions of UNIX.

Exercises

24.1	What is meant by saying that UNIX is a procedural system? How might the hardware support or assume this style of system design (see Sections 9.3 and 5.8 for an example)? ...