Disk Drives And Files

    A computer by itself is about as
useful as roller skates in a swimming
pool.  To be of any use, it needs
information. Information is divided
into two categories, data and
programs.  Data takes many forms,
including pictures, text, numbers or
sound effects. Programs are sets of
instructions telling the computer how
to operate on the data.
    Programs and data live in files.
A file is a named group of magnetic
codes, usually stored on a disk.
    Most computers have a built in
hard disk.  It is a stack of disks
which spin very fast.  They are
coated with magnetic material on
which electrical signals can be
recorded, just like a video tape
holds a movie.
    Since the hard disk is built in,
most computers are also equipped with
one or more floppy disk drives and
possibly a CD-ROM drive.  Floppy
disks make an excellent way to store
and transport programs from one
computer to another. A CD-ROM disk can
hold as much data as a large hard
disk, but it is slower.
    When a typical computer starts,
it offers a "C Prompt" which looks
like this:

C:\>

The C means disk drive C, which is
usually the hard disk. The first
floppy drive is designated as A, and
if there is a second floppy drive, it
is B.  A CD-ROM is often disk drive
D, although the exact letter may
vary, since a second hard disk or a
portion of the main hard disk can be
designated with it's own letter.
    To perform an operation on a disk
in a specified drive, type the drive
letter, a colon, then the filename.
Example:

COPY C:MYFILE A:YOURFILE

   This example copies a file called
MYFILE from the hard disk C to a
floppy disk in drive A, and names the
new copy YOURFILE.
   If you do not specify a drive,
then the operation will be performed
on the default drive.  The default
drive letter is indicated as part of
the "C Prompt."  This works exactly
the same as the previous example:

COPY MYFILE A:YOURFILE

    To switch drives, you type
disk letter followed by a colon
(capital semi-colon) on the command
line (the DOS prompt), and press
[Enter].  If switching to a floppy or
CD-ROM, there ought to be a disk in
the drive first, otherwise DOS will
wait quite a long while for you to
insert a disk.
    If you switch to drive A by
typing A: (and press [Enter]) then
your "C Prompt" becomes an A Prompt.
It will look like this:

A:\>_

This is called "logging to drive A."
    To see a list of files on a disk,
type DIR and press [Enter]. If there
are more files than will fit on the
screen at one time, use DIR/P to
pause the list.

    If you are logged onto drive C,
and want to see which files are on a
floppy in drive A, you can type:

DIR A:

or

DIR A:/P

to pause the list.

   If there are hundreds or even
thousands of files on a disk, they
may be structured in directories,
which are like folders in a filing
cabinet.  See the section about
directories for more information.

_____________________________________
                         end of file.