The basis for the storage model on the PC, at a logical level, is the file. The
universal concept of the file is one of the strengths of the PC file system, and is one
that the PC shares with many other successful file systems such as that used by UNIX. A
file is simply a collection of bytes stored together with a name to identify it. A file
can contain anything: program code, data, pictures, a movie, you name it. The
meaningfulness of a file, and what it is used for, is determined by what you put in it,
and what software you use it with.
As you probably know, files are stored in virtually every PC-based operating system
using a paradigm known as the directory tree. The "base" of the tree is
the (somewhat appropriately named) root directory. Within the root directory you can
create either files or more directories (often called subdirectories). Each directory is a
container that holds files or more subdirectories (or both). Taken as a whole, the
structure of directories and subdirectories forms a logical tree.
Each file or directory on the hard disk can be uniquely identified using two pieces of
information: its filename, and the path along the directory tree that you traverse
to get to it. For example, let's suppose you have a set of customer information files
organized by region. The entire database is in a directory called "Customers".
Within this is a directory for each state. Within each of these state directories is a
text file called "customer-list.txt". The file containing information about your
customers in Texas would then be addressed as
"\Customers\Texas\customer-list.txt". The filename is
"customer-list.txt", and the path is "\Customers\Texas".
Next: Internal Directory Structures
