from
The Free On-line Dictionary of Computing (8 July 2008)
file system
filing system
<operating system> (FS, or "filesystem") 1. A system for
organizing {directories} and {files}, generally in terms of
how it is implemented in the {disk operating system}. E.g.,
"The {Macintosh file system} is just dandy as long as you
don't have to interface it with any other file systems".
2. The collection of files and directories stored on a given
drive (floppy drive, hard drive, disk {partition}, {logical}
drive, {RAM drive}, etc.). E.g., "mount attaches a named file
system to the file system hierarchy at the pathname location
directory [...]" -- {Unix manual page} for "mount(8)".
As an extension of this sense, "file system" is sometimes used
to refer to the representatation of the file system's
organisation (e.g. its {file allocation table}) as opposed the
actual content of the files in the file system.
{Unix manual page}: fs(5), mount(8).
(1997-04-10)