Understanding filesystems and devices

The UNIX system provides access to information by mapping it within a notional name space. A name space is simply an abstract space within which all entities are identified by name; items existing in the system name space are files of data (including directories), and special files (such as devices) which provide access to hardware devices such as tapes, terminals or hard disks. Given the name of an entity, the kernel can retrieve it and read its associated data. However, the fact that the entities can all be referred to by the same method should not be confused with equivalence; devices, although they look like files, are not files.