VFS: the Filesystem Switch
Sun Microsystems introduced the virtual file system interface in 1985 to accommodate diverse filesystem types cleanly.
VFS allows diverse specific file systems to coexist in a file tree, isolating all FS-dependencies in pluggable filesystem modules.
VFS was an internal kernel restructuring
with no effect on the syscall interface.
Incorporates object-oriented concepts:
a generic procedural interface with
multiple implementations.
Based on abstract objects with dynamic
method binding by type...in C.
Other abstract interfaces in the kernel: device drivers,
file objects, executable files, memory objects.