PC/MS-DOS THE ESSENTIALS A Brief Guide for Users
A Brief Guide for Users
In order for you to use your computer effectively, there are
a few basic commands from PC/MS-DOS you need to learn. In
addition, you need to understand your computer's disk drives
and the proper care and handling of floppy disks.
This brief manual, designed for new computer users, will
help you get the most from your computer. It is organized
according to the most frequently used commands. An index at
the back of the manual will help you find the sections you
For each command, I have provided an explanation of the
command, plus information on how to use the command in
several situations. The examples should help you perform
the operations you will use every day.
There are a few conventions used in this manual which you
need to know:
1. When you see a word surrounded by <>, that means to press
the key marked with that word. For example, if you see
this: , press the Enter (<__|) key.
2. In some cases, spaces are important to a command. In
those cases, you will see this: (sp). When following an
example, press the spacebar when you see (sp).
3. Otherwise, type the command as it is written in the
DISK DRIVES AND FLOPPY DISKS
There a two basic types of disk drives you are likely to
1. Floppy disk drives.
2. Hard disk drives.
Your computer will have at least one floppy disk drive. It
may well have two. These drives have names. The left or
top drive is usually called Drive A:. The right or lower
disk drive (on two-drive systems) is usually called Drive
Depending on your system, you may also have one or more hard
disk drives. If you have one hard disk, it will probably be
named Drive C:
All DOS commands refer to these drive names. In order for a
command to act on a drive, you must specify the correct
drive name. For example, the command Format b: acts on
Drive B:. If you supply the wrong drive name, you may
destroy data on a drive.
IMPORTANT: If you give a command without specifying a drive
name, the computer assumes you are referring to the drive
name specified at the system prompt. That prompt looks like
Any command you give while this prompt is on the screen will
act on Drive A:. This can lead to problems. If you enter
the command FORMAT while you are using Drive C:, you may
destroy all the files on Drive C:. Get into the habit of
ALWAYS specifying the drive name when entering a command.
NOTE: All DOS commands must be given while the system prompt
(A> or C>) are on the screen. If you make an error when
entering a command, use the backspace key to delete
characters, not the left arrow key on the number pad.
Floppy disks are the most common method of storing programs
and data for your computer. There are three basic types:
1. 5 1/4" double-sided/double-density floppy disks.
2. 5 1/4" double-sided/high-density floppy disks.
3. 3 1/2" floppy disks.
The typical computer uses the first type. It can store 360
Kbytes of data, or about 150 pages of double-spaced type.
Most often, these disks are marked DS/DD 48tpi.
The second type, used only on IBM PC/AT or compatible
computers, can store 4 times as much data. They are marked
The third type of floppy disk is used primarily on portable
computers. It can store 720 Kbytes of data, twice as much
as the first type of disk.
If you have an AT-type computer, its disk drives can read
data written on the first type of disk. However, disks
written on the High-density drives cannot be read by other
Many times, AT-type computers use a 360 Kbyte disk drive as
drive B:. If this is the case, record all files to be read
on other computers on drive B:.
INSERTING A FLOPPY DISK
Hold the disk with its label up, then insert it into the
disk drive. When it is fully inserted, close the drive door
with the lever, or push the drive button.
Some computers have their drives in a vertical position.
When inserting a disk into this type of drive, the label
should face left.
CARE FOR FLOPPY DISKS
Floppy disks are a very reliable storage device, but they
require some care. Here a some simple rules:
1. Never touch the disk surface in the exposed windows.
2. Store disks in cool, dry places. Disk storage boxes are
3. Keep floppy disks away from magnetic fields, such as
motors, telephones, and other electrical devices.
4. Handle disks with care. Avoid bending them.
5. When writing on disk labels, use a felt-tip pen when the
labels are attached to the disk. Avoid excess pen pressure.
6. Keep floppy disks in their protective sleeves whenever
they are not in the disk drive.
7. Store backup copies of important disks away from your
work space. If problems occur, your programs and data will
be in another location, and can be retrieved.
8. Avoid spilling anything on a floppy disk. Keep coffee
and other beverages away from your computer and work areas.
9. Never remove a disk from its drive while the drive light
is on. This can cause you to lose all data on the disk.
10. Avoid subjecting floppy disks to static electricity.
Ground yourself by touching a grounded object if you have
been walking on carpets or if there is static in the air.
HARD DISK DRIVES
Hard disk drives, on the other hand, are more permanent.
You do not remove the disk; it remains in the drive at all
A typical hard disk drive holds from 10 to 40 megabytes of
data. This allows you to store the equivalent of up to 100
floppy disks or more on a single hard disk drive.
Hard disk drives are typically named C: or D:. Your
computer probably starts up with from the hard disk drive if
no disks are in drive A: or drive B:
Hard disks pretty much take care of themselves, with one
exception. If your hard disk does not have an automatic
head parking feature (see the owner's manual), you should
use the program supplied with the drive to park the head
whenever you turn off your computer. The owner's manual
which came with your drive will provide this information,
along with the name of the parking program.
FILES AND FILENAMES
Every program on your computer, and your data, is stored in
files on your disk drives. There are a few things you need
to know about files.
Each file must have its own, unique filename. You may
already be familiar with the structure of filenames, but
here is a rundown.
Each filename is made up of two parts: 1. File Name 2.
Extension. Let's look at a typical file:
File Name Extension
The File Name may be up to 8 characters long, and may
contain letters and numbers. It is separated from the
Extension by a period or decimal point.
The Extension, which can be up to 3 characters, can also be
made up of both letters and numbers.
Combined, the two parts of the filename can help you
identify a particular file. Choose a filename for each file
carefully, to help you find that file later.
Certain extensions are reserved by DOS for specific types of
files. .COM, .EXE, .BAS, and .BAT are reserved extensions,
and should not be used for ordinary files.
Certain punctuation characters can be used in filenames,
while others cannot. For simplicity's sake, avoid the use
of punctuation characters in your filenames.
Before going on to discuss individual DOS commands, here are
a few facts about command structure:
There are two basic types of DOS commands:
1. Internal commands.
These commands, like COPY, DEL, and TYPE, are stored in your
computer's memory and can be used anytime you see the system
prompt. Many of the most-used commands fall into this
2. External commands.
This group of commands are stored on your disk. To use
them, either insert the DOS floppy disk, or change to the
directory on your hard disk which contains DOS external
commands. See the directory section of this manual for more
details. Examples of external commands include FORMAT,
DISKCOPY, and CHKDSK.
The section of this manual devoted to each command will tell
you whether the command is internal or external.
Some commands can take several forms. These separate forms
are used by including various parameters with the command.
Parameters, which will be discussed with each command, are
indicate by a / mark. Here is an example of a command with
an attached parameter:
All DOS commands must be activated by pressing the
key after typing the command.
NOTE: You can type all DOS commands in either upper or lower
The rest of this manual will present DOS commands in
alphabetical order. Only the most common commands are
included. For information on other commands, see your DOS
CHDIR is an internal command.
If your computer has a hard disk drive, some of the programs
and data on that drive may be stored in sub-directories. If
so, they will be marked as subdirectories. To check this,
type DIR at the C> or D> prompt. Sub-directories will be
shown like a filename, but with in the place of an
The CHDIR command allows you to change to any of the sub-
directories. You need to do this to use the programs in any
To change to a sub-directory called WP, type the command as
The command can be abbreviated to CD:
After executing this command, you will be in the WP
directory. To go back to the main directory, type the
CHDIR(sp).. or CHDIR\
CD(sp).. or CD\
Commands given while in a sub-directory act on that
CHKDSK is an external command.
The CHKDSK command allows you to check any disk on your
computer. It looks for bad sectors on the disk and also
tells you how much memory is available on your computer.
Use this command from time to time to check important floppy
disks and to check your hard disk drive for problems. If
you begin to see bad sectors on your hard disk drive, and
the number of bad sectors starts to increase, the hard disk
drive may be developing problems. Remember: most hard disk
drives have some bad sectors, so watch for increases.
To check the disk in drive A:, use the following command:
To check your hard disk:
You can substitute any drive name.
NOTE: Since this is an external command, you must insert
your DOS disk in drive A: or CHDIR to the directory which
contains DOS external commands on your hard disk.
CLS is an internal command.
The CLS command clears your computer's screen and moves the
system prompt to the top of the screen.
To clear the screen, type the following command:
COPY is an internal command.
The principal use of the COPY command is to copy files from
one disk or directory to another. It's use is very simple.
To copy the file LETTER.DOC from drive A: to drive B:, enter
the following command:
To copy LETTER.DOC to Drive B: and change its name on drive
B: to LETTER1.DOC, type the following:
To copy LETTER.DOC from the WP sub-directory on drive C: to
drive B:, use this format:
DOS also allows you to copy more than one file at once. Two
symbols, called wildcards, allow you to specify groups of
files. Here are the wildcards:
* indicates any group of characters.
? indicates a single character.
To copy all the files with the extension .DOC from drive A:
to drive B:, use this command:
To copy ALL files from drive A: to drive B:
NOTE: Wildcards will not copy files within subdirectories,
unless you are in that subdirectory or have a path statement
including the subdirectory.
To copy LETTER1.DOC, LETTER2.DOC, etc. from drive A: to
NOTE: If you are copying to a blank diskette, you must
FORMAT the diskette first.(See the FORMAT command)
The COPY command, along with most other DOS commands can be
used with PATH statements to copy files into subdirectories.
See the section on the PATH command for more information.
DEL or ERASE
DEL and ERASE are internal commands.
These commands are identical, and can be used
interchangeably. The delete files from a disk, so use them
To delete LETTER.DOC from drive B:
Similarly, to delete LETTER.DOC from the directory WP on
You can use wildcard characters with DEL and ERASE, in the
same way you did with the COPY command.
To delete all files with the extension .DOC from drive B:
To delete ALL files from drive B:
Any time you use the *.* wildcard to delete files, the
computer will ask you:
Are you sure Y/N?
Check what you are doing, then, if you are sure you want to
delete all files from that disk, type Y, then press the
As with the COPY command, path information can be added to
the drive specification, if needed.
CAUTION: Use extreme care when using wildcards with the DEL
or ERASE command. Pay special attention to the drive name
you have designated. It is possible to inadvertently delete
all files on your hard disk with a single keystroke. BE
DIR is an internal command.
The DIR command allows you to see a list of the files stored
on any disk. Along with the filenames, it also provides
other information about the files.
To see a list of files on drive A:
You will see a list of files, along with the size of each
file in bytes, and the date and time that data was last
entered in that file. In addition, the amount of space left
on the disk will be displayed.
Sometimes, a disk will have more files than can be displayed
on the screen. Using the DIR command will cause the files
to scroll off the top of the screen faster than you can read
them. To avoid this, add the parameter /P. Here is an
DOS will fill the screen with file information, then print
at the bottom of the screen:
Press a key to continue:
After you press ANY key, another screenfull of data will be
displayed. This continues until the entire directory has
There is another option with DIR. To see a list of files on
disk A:, arranged in multiple columns, but without file size
and other information:
NOTE: Use the DIR command frequently to check on the files
on your disks and to keep track of the amount of disk space
DISKCOPY is an external command.
Use DISKCOPY to make exact duplicates of floppy disks. You
can only use this command on floppy disk drives, typically
drive A: and drive B:
To copy a disk on a single drive computer:
The computer will ask you to:
Place the SOURCE diskette in Drive A: then press Enter.
After pressing the Enter key, the computer will read all the
data on the disk, then ask you to:
Place the TARGET diskette in Drive A: and press Enter:
Remove the original disk, and replace it with a blank disk.
After you press Enter, the data will be copied onto the
On a computer with two floppy disk drives:
You will see the following:
Place SOURCE diskette in Drive A:
Place TARGET diskette in Drive B:
Strike a key when ready:
Place the original disk in drive A: and the blank disk in
drive B:. Press a key, and the computer will make a copy
When the process is complete, you will see:
Make another copy? Y/N?
Enter a Y to start the process again, or N to return to the
Note: If the new disk is not formatted, DISKCOPY will
automatically format it before copying.
CAUTION: Make sure the second disk does not contain data,
since the DISKCOPY command will destroy any data on the
You cannot use the DISKCOPY command with drives other than
A: or B:.
FORMAT is an external command.
Before you can write data onto a floppy disk, it must be
formatted to hold the data. DOS has a command which does
To format a disk in Drive A:
You will see on the screen:
Insert a new diskette for Drive A:
Press ENTER when ready.
Place an unformatted disk in Drive A: and press the Enter
key. DOS will format the disk and make it ready to accept
data. When the process is complete, you will see:
Format Complete: Format another? Y/N?
If you want to format more diskettes, press Y, and the
process will repeat. If not, press N and you will return to
the system prompt.
CAUTION: Like DISKCOPY, FORMAT destroys all data on the
disk. Use caution when formatting disks.
WARNING!!!! In some versions of DOS, FORMAT can act on
Drive C: or other hard disk drives. If it does, all data on
your hard disk will be destroyed. Because of this, ALWAYS
indicate the drive to be formatted. Check your typing
carefully when using this command.
MKDIR is an internal command
The MKDIR command allows you to create new sub-directories.
To create a new subdirectory, called CHAPTER1 on drive C:
To create a subdirectory within a subdirectory, for example
to create the subdirectory CHAPTER1 in the directory NOVEL
on drive C:
If you are already in the directory in which you want to
place a subdirectory, you do not need the \ character. For
example, If you had used the CHDIR or CD command to move to
the NOVEL subdirectory, create the CHAPTER1 subdirectory
Note: You can abbreviate the MKDIR command to MD.
CAUTION: Be certain you know which directory you are in
before using the simplified form of this command. Otherwise
you may create a subdirectory in an unwanted place. To
avoid confusion, use the full format, including drive name,
as in the first and second examples.
PATH is an internal command.
If your computer has a hard disk drive, many of the programs
you use, along with data files, will be stored in
subdirectories. Normally, you have to change directories
with the CHDIR (CD) command to get access to files.
DOS provides another method with the PATH command. This
command allows you to tell DOS where to look for your files.
You can instruct the computer to look in several places for
any file you name in another command, or from a program.
To tell DOS to look for your wordprocessing programs and
files for the NOVEL subdirectory, as used as an example in
other parts of this manual:
Using this format, DOS will automatically search the \WP
directory and the \NOVEL subdirectory for files when you
give a command from any other directory.
Now, suppose you have a number of programs you use
frequently. They are in different subdirectories with the
following names: \DB \WP \123 \MAIL & \SALES.
In addition, there are further subdirectories, such as
\NOVEL in the \WP directory and \BUSINESS and \PERSONAL in
the \MAIL directory.
The following command will allow you access to all the
programs listed above:
Notice that the main directories are separated with semi-
colons, while subdirectories of these directories are
specified with the backslash (\) character.
NOTE: If a path you specify does not exist, DOS will give
the following message:
If DOS cannot find the file you specify in any of the
subdirectories, this message will appear:
Bad command or filename
In either case, check your path command to make certain it
is correct. If you type PATH without any other
information, DOS will display your current path designation.
NOTE: Along with the directory names, you can also include
drive names in a PATH command. Use this feature to make DOS
look on your floppy drives for files.
REN is an internal command.
Use the REN command to change the name of a file.
To change the file LETTER.DOC to LETTER2.DOC:
RMDIR is an internal command.
RMDIR, or its abbreviated form RD, removes a subdirectory
from a disk. Before removing the directory, however, all
files in that directory must be deleted with the DEL or
To remove the \WP directory from your hard disk:
Enter the following series of commands.
CAUTION: Be certain that you really want to delete all the
files in that directory. If there are files you wish to
save, COPY them to another directory, or to a floppy disk
before deleting them.
TYPE is an internal command.
Use the TYPE command to view the contents of a file on your
monitor. This command is useful only on ASCII files,
meaning files which contain only text. This excludes all
program files, as well as most files created by your word
To see the file AUTOEXEC.BAT on drive A:
You can also specify a path for this command. To see the
file LETTER.DOC in the \WP directory on drive C:
NOTE:This command will scroll the file on the screen, too
fast for you to read. Special utility programs are
available which will let you see the file one screen at a
time. Most of these files are Public Domain programs and
are available without charge from Public Domain software
When you make a mistake when entering a command, or if
another type of problem occurs, DOS will place an error
message on the screen. The following are the most common
messages you will see. Suggestions for correcting the error
are provided following the message.
Bad command or file name
DOS cannot find the file or command you entered. Check your
typing and the PATH you have specified for errors.
Disk Drive Error: Abort, Ignore, Retry?
DOS has detected an error on a disk drive. Most often, this
message appears when you have forgotten to insert a floppy
disk into the drive, or have failed to close the door.
Correct the problem, then press R for retry. Pressing A
returns you to the system prompt.
If this message should appear when you are trying to access
your hard disk drive...STOP. Get help from someone who
knows the system well.
File cannot be copied onto itself
You have tried to copy a file to the same filename on the
same drive. Check your command.
File not found
DOS can't find the file you specified. Check your typing
and make sure you have given the correct path.
An error has occured when using the FORMAT command. DOS
will provide an explanation with this error message. Take
the appropriate corrective measures.
Insufficient disk space
The disk you are working with does not have enough space to
hold the data. Replace with a new, formatted disk and
repeat the operation.
Your computer does not have enough memory for the operation
you have named. Consider expanding your system's memory
size. Memory expansion is relatively inexpensive.
Invalid Disk Drive
The drive name you specified does not exist on your
computer. Check your typing.
Invalid number of parameters
You have mis-typed the command or specified information not
acceptable to DOS. Check the command for errors.
There are many other error messages you may see on your
screen. For information on these errors, consult your DOS
WHEN YOUR COMPUTER CRASHES
No matter how careful you are, there will be times when your
computer gets confused. Usually, when this happens, the
keyboard will lock up and nothing you type will have any
effect. Other problems sometimes occur, including a drive
that won't stop running.
When using commercial software, these problems are
infrequent, but do happen from time to time. Most often,
you will lock your system up when experimenting with public
domain software, which is less bug-free than most commercial
There are four ways to get out of a locked system. Try
these in the order shown below.
1. Hold down the key while you press the key. This will often get you out of the program
and return you to the system prompt. If it does, you're
back in business.
2. Press the , , and
keys at the same time.
Hold each key down as you press the others. This is called a
"warm boot." It usually does the trick, but wipes out
whatever information is stored in your computer's memory.
3. Press the switch, if your computer has one. This
will reboot the computer, wiping out all data in current
4. Finally, if none of the other methods work, turn off the
computer, wait a few seconds, then turn it back on. As
before, data stored in memory will be lost. This last
method is absolutely guaranteed, however, to restart your
CARE FOR FLOPPY DISKS............................4
DEL or ERASE....................................10
DISK DRIVES AND FLOPPY DISKS.....................3
FILES AND FILENAMES..............................6
HARD DISK DRIVES.................................5
INSERTING A FLOPPY DISK..........................4
WHEN YOUR SYSTEM CRASHES........................20