Learning more about virtual file systems

Tcl, like almost every programming language, allows you to operate on files and directories existing in the underlying file system. In the 'good old days', the Tcl interpreter was able to operate only on native filesystems specific to the operating system it was compiled for. From version 8.4, Tcl incorporates the concept of virtual file systems (VFSs). The idea is to separate normal Tcl commands from the real file system calls. Such separation makes it easy to add support for additional filesystems, because all that is required is to create appropriate drivers. VFS allows us to redirect all FS related calls to the driver responsible for the proper handling of these calls.

Luckily for us, there is already a Tcl extension called tclvfs (http://sourceforge.net/projects/tclvfs/) that offers a number of drivers for various virtual file systems. The word 'virtual' means that the code operates in a unified manner on files / directories located inside something...