12.1. The Unix Filesystem: Making the Physical Virtually Accessible
If the Unix kernel is the heart of the operating system, then the filesystem
is it's soul. However one uses the term, the filesystem usually refers
to the entity which contains all the data for the workstation or
server: system data, user data and all binary executable programs runnable on
the machine.
The word "filesystem" under Unix can mean different things. It can
refer to the hierarchical Unix directory tree structure or the
the virtual filesystem or the
physical filesystem, depending on the context:
- Virtual filesystem or the Unix directory tree
- The hierarchical representation of files and directories of files,
with which a user or administrator may perform various functions:
e.g. editing, viewing, executing, etc. This is the Unix interface
to the physical filesystem. Many Unix resources (including
hardware) are available via the virtual filesystem.
-
- Physical filesystem
- The collection of data represented by the virtual filesystem. The
physical filesystem may be arranged on one or more actual storage
devices, typically hard disks. The layout across disks may be
contiguous or "striped", possibly mirrored and in special cases
integrated with a massive storage tape system.