Introduction

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.
For each command, there has been 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 article 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: [Enter], press the Enter or Return 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 example.




disk DRIVES AND FLOPPY disks

There a two basic types of disk drives you are likely to encounter:
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 B: .
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 to the format command, 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 this:
A>
Or on PCs in Electronic Engineering, this may give the directory name as well, as in:
A:\>
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

Floppy disks are the most common method of storing programs and data for your computer. There are four 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" double-sided/double-density floppy disks.
4. 3 1/2" double-sided/high-density floppy disks.
The first IBM PC/XT or compatible computers used the first type, which is now largely confined to older models. It can store 360KB of data, or about 150 pages of double-spaced type. It has a flexible jacket and slots where the magnetic medium is visible (DO NOT TOUCH THAT). 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, i.e. 1.2MB. They are marked DS/HD 96tpi.
The third type of floppy disk is used primarily on older models of portable computers, or on non IBM-compatibles like the Atari 1040ST. It can store 720KB of data, twice as much as the first type of disk. It has a rigid jacket, commonly blue, and a shutter over the magnetic medium, so it is more durable.
The fourth type of floppy disk is the most common sort on newer models of all types. It can store 1.4MB of data (also called 1.44MB, since it holds 1440KB), four times as much as the first type of disk. It has a rigid jacket, and a shutter over the magnetic medium, so it is more durable. Most often, these disks are marked HD; they tend to be black.
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 PC-compatible computers.
Similarly, disks recorded as 1.4MB cannot be read on 720KB-only drives. However, 720KB disks are generally interchangeable.
Many times, computers with the higher capacity disk drives as drive A: will use a 360KB disk drive as drive B:. If this is the case, record all files to be read on older 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 if present. To remove the disk (when it is no longer in use), open the drive door with the lever if present, or push the eject 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 ideal.
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 times.
A typical hard disk drive holds from 40 to 100MB 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:

FileName

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.




DIRECTORY NAMES

Directories are named like files, with up to eight characters and an optional dot followed by up to three characters. They generally do not have an extension, for simplicity. Directories contain your files, but can also contain other directories, so as to make up a tree-like structure. To refer to a file in a directory (such as when the same name is used for files in different directories), put the name of its directory (and the name of the directory containing that, and so on) separated by a "\" character.
So for a complete specification of where a file lives on disk, you might put:
\users\fred\wp\thesis\chapter1.txt
This is called an absolute pathname. If you are in the "wp" directory at the time, you can put just:
thesis\chapter1.txt
This is called a relative pathname; notice it does not begin with a "\".




DOS COMMANDS

Before going on to diskuss 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 category.

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.
This next section is devoted to each command and 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 diskussed with each command, are indicate by a "/" mark. Here is an example of a command with an attached parameter:




DIR/W

All DOS commands must be activated by pressing the [Enter] key after typing the command. NOTE: You can type all DOS commands in either upper or lower case letters.
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 manual.




CHDIR

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 [DIR] in the place of an extension.
The CHDIR command allows you to change to any of the sub-directories. You need to do this to use the programs in any sub-directory.
EXAMPLE:

To change to a sub-directory called WP, type the command as shown below:
CHDIR(sp)\WP [Enter]
The command can be abbreviated to CD:
CD(sp)\WP [Enter]
After executing this command, you will be in the WP directory. To go back to the main directory, type the following command:
CHDIR(sp).. [Enter] or CHDIR\ [Enter] -or- CD(sp).. [Enter] or CD\ [Enter]
Commands given while in a sub-directory act on that directory only.




CHKDSK

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.
Example:
To check the disk in drive A:, use the following command:
CHKDSK(sp)A: [Enter]
To check your hard disk:
CHKDSK(sp)C: [Enter]
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

CLS is an internal command.
The CLS command clears your computer's screen and moves the system prompt to the top of the screen.
Example:
To clear the screen, type the following command:
CLS [Enter]




COPY
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.
Example:
To copy the file LETTER.DOC from drive A: to drive B:, enter the following command:
COPY(sp)A:LETTER.DOC(sp)B: [Enter]
To copy LETTER.DOC to Drive B: and change its name on drive B: to LETTER1.DOC, type the following:
COPY(sp)A:LETTER.DOC(sp)B:LETTER1.DOC [Enter]
To copy LETTER.DOC from the WP sub-directory on drive C: to drive B:, use this format:
COPY(sp)C:\WP\LETTER.DOC(sp)B: [Enter]




Wildcards

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.
Example:
To copy all the files with the extension .DOC from drive A: to drive B:, use this command:
COPY(sp)A:*.DOC(sp)B: [Enter]
To copy ALL files from drive A: to drive B:
COPY(sp)A:*.*(sp)B: [Enter]
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 drive B:
COPY(sp)A:LETTER?.DOC(sp)B:[Enter]
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. These delete files from a disk, so use them carefully.
Example:
To delete LETTER.DOC from drive B:
DEL(sp)B:LETTER.DOC [Enter]
Similarly, to delete LETTER.DOC from the directory WP on drive C:
DEL(sp)C:\WP\LETTER.DOC [Enter]
You can use wildcard characters with DEL and ERASE, in the same way you did with the COPY command.
Example:
To delete all files with the extension .DOC from drive B:
DEL(sp)B:*.DOC [Enter]
To delete ALL files from drive B:
DEL(sp)B:*.* [Enter]
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 Enter key. 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 CAREFUL!




DIR

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.
Example:
To see a list of files on drive A:
DIR(sp)A: [Enter]
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 example:
DIR(sp)B:/P [Enter]
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 been presented. 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:
DIR(sp)A:/W [Enter]
NOTE: Use the DIR command frequently to check on the files on your disks and to keep track of the amount of disk space available.




diskCOPY

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:
diskCOPY [Enter]
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 blank disk.
On a computer with two floppy disk drives:
diskCOPY(sp)A:(sp)B: [Enter]
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 for you. 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 system prompt.
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 disk.
You cannot use the diskCOPY command with drives other than A: or B:.




FORMAT

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 this automatically.
To format a disk in Drive A:
FORMAT(sp)A: [Enter]
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

MKDIR is an internal command
The MKDIR command allows you to create new sub-directories.
Example:
To create a new subdirectory, called CHAPTER1 on drive C:
MKDIR(sp)C:\CHAPTER1 [Enter]
To create a subdirectory within a subdirectory, for example to create the subdirectory CHAPTER1 in the directory NOVEL on drive C:
MKDIR(sp)C:\NOVEL\CHAPTER1 [Enter]
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 like this:
MKDIR(sp)CHAPTER1 [Enter]
Note: You can abbreviate the MKDIR command to MD.
Example:
MD(sp)CHAPTER1 [Enter]
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

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.
Example:
To tell DOS to look for your word processing programs and files for the NOVEL subdirectory, as used as an example in other parts of this article:
PATH(sp)\WP\NOVEL [Enter]
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 and \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:
PATH(sp)\DB;\WP\NOVEL;\123;\MAIL\BUSINESS\PERSONAL;\SALES [Enter]
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:
No Path
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 [Enter] 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 looks on your floppy drives for files.




REN

REN is an internal command.
Use the REN command to change the name of a file.
Example:
To change the file LETTER.DOC to LETTER2.DOC:
REN(sp)LETTER.DOC(sp)LETTER2.DOC [Enter]




RMDIR

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 ERASE commands.
Example:
To remove the \WP directory from your hard disk, enter the following series of commands:
CD(sp)\WP [Enter]
DEL(sp)*.* [Enter]
CD(sp).. [Enter]
RMDIR(sp)\WP [Enter]
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

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 processing program.
Example:
To see the file AUTOEXEC.BAT on drive A:
TYPE(sp)A:AUTOEXEC.BAT [Enter]
You can also specify a path for this command. To see the file LETTER.DOC in the \WP directory on drive C:
TYPE(sp)C:\WP\LETTER.DOC [Enter]
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 suppliers.




ERROR MESSAGES

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.

Format failure
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.

Insufficient memory
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 manual.




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 programs.

There are four ways to get out of a locked system. Try these in the order shown below.

1. Hold down the [Ctrl] key while you press the [Scroll Lock/Break] 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 [Ctrl], [Alt], and [Del] 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 [Reset] switch, if your computer has one. This will reboot the computer, wiping out all data in current memory.

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 system.