UNIX Filesystems: Evolution, Design, and Implementation

Summary

This chapter concentrated on the structures introduced in the early UNIX versions, which should provide readers with a basic grounding in UNIX kernel principles, particularly as they apply to how filesystems and files are accessed. It says something for the design of the original versions of UNIX that many UNIX based kernels still bear a great deal of similarity to the original versions developed over 30 years ago.

Lions' book Lions' Commentary on UNIX 6th Edition [LION96] provides a unique view of how 6th Edition UNIX was implemented and lists the complete kernel source code. For additional browsing, the source code is available online for download.

For a more concrete explanation of some of the algorithms and more details on the kernel in general, Bach's book The Design of the UNIX Operating System [BACH86] provides an excellent overview of System V Release 2. Pate's book UNIX Internals—A Practical Approach [PATE96] describes a System V Release 3 variant. The UNIX versions described in both books bear most resemblance to the earlier UNIX research editions.