This article over at IBM, provides information VFS. A virtual filesystem (VFS) is an abstraction with surprisingly productive uses. Several popular languages now support VFS constructs, including Java and Perl. Tcl’s filesystem is completely virtual filesystem aware and is way ahead of other languages in its VFS sophistication. The concept should intrigue anyone working with Linux, of course, simply because so much of Linux’s own character comes from the representation of devices, tables, and other objects within the UNIX filesystem.