UNIX Filesystems: Evolution, Design, and Implementation

Non-SVR4-Based Filesystem Architectures

Previous chapters have centered around the main evolutionary path that UNIX took from the early research editions through to System V Release 4, which involved the last major enhancements to the UNIX filesystem architecture.

While many different UNIX and UNIX-like vendors adopted the Sun VFS/vnode interface to one degree or another, their implementations differed in many other areas, most notably in how file I/O takes place. Some of the microkernel implementations offered new approaches to supporting UNIX-based filesystems.

This chapter describes the major different UNIX and UNIX-like operating systems from a filesystem perspective, showing the similarities and differences to the pre-VFS and post-VFS/vnode implementations.