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Batch Files

     A batch file contains a series of commands that DOS executes 
sequentially whenever you enter the name of the batch file and 
press Enter at the DOS prompt. The batch file name must contain 
the extension .BAT to execute. However, when running a batch 
file, you do not enter the .BAT extension as part of the command 
file name.
     The batch file is saved as a DOS text file (in ASCII 
format). It can contain DOS commands and/or special batch file 
commands that are used only in batch files.
     Batch files are frequently used to automate the execution of 
a group of commands that you find yourself having to enter 
manually over and over. These can include typical start-up, 
maintenance, and backup procedures as well as such simple tasks 
as renaming specific DOS commands to make them easier to remember 
and access (such as FORMAT A: to PREPARE).
     Each command statement in the batch file is listed by line 
in the file, and DOS executes each statement in the order in 
which it is entered in the batch file. DOS will terminate the 
batch file as soon as it has executed the last command statement 
in the file. To terminate a batch file at any time before this, 
issue the BREAK command (either by pressing Ctrl-C or Ctrl-
Break). When you issue the BREAK command during the execution of 
a batch file, DOS displays the message

Terminate batch job (Y/N)?

     To have DOS to ignore the current command statement and 
execute the next command statement, thereby continuing the 
running of the rest of the batch file, type N. To terminate the 
execution of the current and all remaining command statements 
(that is, abort the batch file), type Y. (Note that some versions 
of DOS require that you press Enter after typing Y or N. Also, 
some commands that can be entered in a batch file will not 
respond to the BREAK command.)

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		  [For related topics, press R]

    SEE ALSO

     AUTOEXEC.BAT File
     Chaining of Batch Files
     COMMAND Command
     Conditional Processing
     Creation of Batch Files
     DATE Command
     Displaying of Text with Batch Files
     ECHO batch file command
     Loops in Batch Files
     PRINT Command
     Replaceable Parameters in Batch Files
     Subroutines for Batch Files


Creation of Batch Files
     You can create a batch file using the COPY command, EDLIN 
(the line editor supplied with DOS), or any other editor or word 
processor that can save its text in ASCII format. When creating 
or saving the batch file, be sure to append the extension .BAT to 
the file name you assign to it.
     To create a batch file using the COPY command, use 
the paradigm

	  COPY CON filename.BAT

where

filename	    Specifies the name you wish to assign to the
                    batch file.

     After entering this, you simply type in each command 
statement in the order you wish it to be processed when the batch 
file is executed. After typing in each command statement, you 
terminate the line by pressing the Enter key.
     Once you have entered all of the command statements you wish 
to have in your batch file, you save it on disk (in the current 
directory) by pressing Ctrl-Z (you can also accomplish this by 
pressing F6 on IBM PCs and most compatibles) and the Enter key.

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO

     Batch Files
     AUTOEXEC.BAT File
     Displaying of Text with Batch Files
     ECHO batch file command
     Replaceable Parameters in Batch Files
     Loops in Batch Files
     Conditional Processing
     Chaining of Batch Files
     Subroutines for Batch Files

A)AUTOEXEC.BAT File

     You can create a special batch file, named AUTOEXEC.BAT, 
which contains all of the DOS commands that you wish to have 
invoked every time you start your computer. The command 
statements in the AUTOEXEC.BAT file often include such DOS 
commands as DATE, TIME, PROMPT, PATH, and SET. These can also 
include commands that execute special RAM-resident programs such 
as Lightning or SideKick or a menu program of your own design. 
Such a program would allow you to start up specific application 
programs available on your PC- -dBASE III PLUS, Lotus 1-2-3, or 
WordPerfect, for example.
     Every time you start your computer, DOS checks for the 
presence of the AUTOEXEC.BAT file on either the disk in drive A 
if you are using a two-floppy disk system, or in the root 
directory of drive C if you are using a hard disk system. If DOS 
locates such a file, it automatically executes the statements it 
contains upon completion of the boot sequence.
     When you create the AUTOEXEC.BAT file, remember to include 
the DATE and TIME commands along with the other commands you wish 
executed each time you start the computer. (If your computer is 
equipped with a clock/calendar card, enter the appropriate 
commands to have the date and time read.) If you do not add 
these commands, DOS will no longer prompt you for the current 
date and time as part of the start-up procedure and, as a result, 
the files you create with your application programs will not be 
stamped with the correct date and time.
     Consider the following example created with the COPY command 
and containing a sampling of DOS commands typically used in the 
AUTOEXEC.BAT file:

	  COPY CON AUTOEXEC.BAT
	  DATE
	  TIME
	  PROMPT $p$g
	  PATH = C:\;C:\DOS;C:\BATCH
	  (Ctrl-Z)

     After creating this AUTOEXEC.BAT file, when you start your 
computer DOS will first prompt you to update the date and time. 
Once you have responded to these commands, DOS changes the prompt 
so that it always displays the current directory, and then sets 
the path so that it will check the root, \DOS, and \BAT 
directories for any command that you enter, regardless of which 
directory you are in at the time.

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		  [For related topics, press R]

    SEE ALSO

     Batch Files
     Creation of Batch Files
     Displaying of Text with Batch Files
     ECHO batch file command
     Replaceable Parameters in Batch Files
     Loops in Batch Files
     Conditional Processing
     Chaining of Batch Files
     Subroutines for Batch Files
     PATH Command
     PRINT Command
     SET Command

A)Displaying of Text with Batch Files

     The batch files that you create can contain messages that 
are displayed to alert the user to the underlying purpose of the 
batch file or to prompt the user to take a particular step- -such 
as changing data disks- -during a pause in the execution of a 
command. You can also add messages that are displayed as part of 
the ECHO command, which controls whether the command statements 
entered in the batch file are displayed to the user as they are 
executed by DOS.
    REM Command

     One way to have text displayed on the screen during the 
execution of a batch command is with the use of the REM (remark) 
command 

	  REM remark

where

	  remark	 Specifies the comment to be added to a
                         batch file.

     DOS will not try to execute a REM command, although it will 
display REM and the text that follows it on the screen unless it 
has previously executed an ECHO OFF statement (see Using the ECHO 
Command, which follows).
     You can use the REM command to add messages to the batch 
file that help make clear its function and procedure. If you wish 
to add a nonprinting comment whose purpose is to document the use 
of particular commands in your batch file but that is never to be 
displayed on the screen to the user, you simply preface the text 
of this type of comment with a colon, as in:

	  :Start backup

Comments prefaced with a colon will appear when you use the TYPE 
command to display the contents of the batch file on your screen, 
or when you use the COPY or PRINT command to obtain a printout.
    PAUSE

     You can also have messages displayed on the screen during a 
pause in the execution of batch file commands. The syntax for the 
PAUSE command is 

	  PAUSE [message]

where

	  [message]	 Specifies the message you want to have
                         displayed on the screen when PAUSE is 
                         invoked.

     When DOS encounters a PAUSE statement, it pauses the 
execution of the commands in the batch file and displays your 
message on the screen, followed by its own message

	  Strike a key when ready. . .

on the line below. If you enter the PAUSE command without any 
message text, you will see only this DOS message instructing you 
to strike a key to continue the execution of the batch file.
     When you use the PAUSE command, the word PAUSE is always
displayed on the screen along with the message you have entered 
(just as when using the REM command). If the batch file has 
executed an ECHO OFF command before it encounters your PAUSE 
command, neither the word PAUSE nor the text of your message will
be displayed on the screen. Only the DOS message about striking a 
key to continue will be visible (see Using the ECHO batch file command, 
which follows).

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO

     Batch Files
     Creation of Batch Files
     AUTOEXEC.BAT File
     Displaying of Text with Batch Files
     ECHO batch file command
     Replaceable Parameters in Batch Files
     Loops in Batch Files
     Conditional Processing
     Chaining of Batch Files
     Subroutines for Batch Files
     PRINT Command
     TYPE Command

A)ECHO

     When DOS executes the commands in a batch file, it can 
display each command statement on the screen as it is executed. 
You can enter the ECHO command in the batch file to control 
whether the command statements are displayed. The syntax is 

	  ECHO	[OFF]

or

	  ECHO	[ON]

where

          OFF            Suppresses the display of command 
                         statements during the execution.
          ON             Used if you wish to have subsequent 
                         commands displayed on the screen during 
                         the execution of the batch file.

     Note that if you enter the ECHO command in a batch file (or 
at the DOS prompt) without using either the ON or OFF parameters, 
DOS responds by displaying the current state of the ECHO command. 
You will see either ECHO is on or ECHO is off.
     If you are using DOS 3.3, you can also suppress the display 
of a command statement in the batch file by prefacing it with the 
@ symbol. For example, entering

	  @VERIFY ON

will prevent the VERIFY ON command from being displayed. However, 
each command statement that you wish to suppress must be prefaced 
by an @ symbol. If you use @ECHO OFF, the ECHO OFF command as 
well as all subsequent statements are automatically suppressed 
until an ECHO ON command occurs.
     When ECHO is off, only the display of the command statements 
in the batch file will be suppressed. DOS will continue to 
display any message that is normally shown after a particular 
commandhas been processed. For instance, if your batch file 
contains the statement

	  ECHO	OFF

followed by a command to copy a particular file from one 
directory to another, you will still see the DOS message

	  1 File(s) copied

although you will not see the contents of the COPY command itself 
on the line above it. Note that you can often get rid of these 
messages by redirecting output to NUL:

	  COPY *.* A: NUL

     You can use the ECHO command to display messages to the 
user. First, set ECHO to off. Then, enter an ECHO command 
followed by at least one space and the text of your message. When 
you use the ECHO command in this way, only your message is 
displayed onthe screen. DOS does not include the command word 
(ECHO) as it does when displaying messages with the REM or PAUSE 
commands.
     For example, you could have your batch file display a prompt 
to insert a data disk in drive A by using the ECHO and PAUSE 
commands as follows:

	  ECHO	OFF
	  .
	  .
	  .
	  ECHO	Insert data disk in drive A
	  PAUSE

When the batch file executes these last two commands, you see 
only

	  Insert data disk in drive A
	  Strike a key when ready. . .

on the screen. ECHO does not appear along with the prompt 
message, but the separate PAUSE command causes the Strike a key
when ready. . . message to be displayed.
     When you use the ECHO command to display messages and 
prompts, be sure that it is preceded by an ECHO OFF statement (or 
an @ symbol if you are using DOS 3.3) in the batch file. 
Otherwise, you will see the ECHO command statement containing the 
message as well as the message itself when the batch file is run.
     Note that the use of the REM, PAUSE, and ECHO commands to 
display on-screen messages slows down the execution of the batch 
file appreciably. If you need to include extensive instructions 
for a particular batch file, use the TYPE command to have them 
displayed on the screen.

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO

     Batch Files
     Creation of Batch Files
     AUTOEXEC.BAT File
     Displaying of Text with Batch Files
     Replaceable Parameters in Batch Files
     Loops in Batch Files
     Conditional Processing
     Chaining of Batch Files
     Subroutines for Batch Files
     COPY Command

A)Replaceable Parameters in Batch Files

     You can define parameters (or arguments) that are passed to 
particular command statements in a batch file with the use of 
replaceable or dummy parameters. This makes the batch file more 
flexible because you get to define the arguments to be passed to 
the command statements at the time you execute the batch file.
     You can define up to ten different replaceable parameters to 
be used in a batch file. Each one is given a number between 0 and 
9 preceded by the percent sign, as in %1, %2, and so on. Note, 
however, that the replaceable parameter %0 represents a special 
case: it is always replaced with the file name of the batch file.
     The other nine replaceable parameters have no such fixed 
replacements: you can make then stand for DOS commands, file 
names, parts of file names (such as extensions), directory paths, 
and the like. For instance, you could use replaceable parameters 
to create a batch file named WHEREIS.BAT that locates a 
particular file for you. This batch file contains only a single 
command statement using the replaceable argument, as follows:

	  CHKDSK /V | FIND ``%1''

The CHKDSK command with the /V parameter lists all of the files 
and subdirectories for the current directory and pipes this 
information to the FIND command.
     The FIND command contains the replaceable parameter %1. When 
you execute the WHEREIS.BAT file, you enter the filename you wish 
to locate along with the batch file name. To locatea file called 
LOAN.FRM on the hard disk, you run the batch fileby entering

	  WHEREIS LOAN.FRM

DOS will then execute WHEREIS.BAT as though you had entered

	  CHKDSK /V|FIND ``LOAN.FRM''

as the command statement. If this file is located in C:\WP\FORMS, 
DOS will respond by displaying

	  C:\WP\FORMS\LOAN.FRM

As you can see, you can use this same batch file to search for 
any file or group of files, simply by entering a different file 
name at the time you execute it.
     In complex batch files, you may find that ten replaceable 
parameters are not sufficient. In such a case, you can use the 
SHIFT command. SHIFT discards each argument after it has been 
acted upon, replacing it with the next argument so that after the 
first argument is processed, the second becomes the first, the 
third the second, and so on. After you use the SHIFT command, the 
0% argument is never acted upon, since the %n argument becomes
the %(n--1) argument. Note that SHIFT is useful in loops, which
are described later in this appendix.
    Passing Arguments from the Environment
     
     As noted in the SET reference entry, you can specify a set 
of strings that the batch files can refer to. For example, if you 
enter the SET command

	  SET REPORT = YREND

and have previously entered the following command line in a batch 
file

	  COPY %REPORT%.WK1 A:

the batch file will copy the file named YREND.WK1 to the floppy 
disk in drive A when the batch file is run.
     Note that the replaceable argument in the batch file command 
line is enclosed in a pair of percent signs (%). This indicates 
to DOS that the argument is to be taken from the environment.

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
     Batch Files
     Creation of Batch Files
     AUTOEXEC.BAT File
     Displaying of Text with Batch Files
     ECHO batch file command
     Replaceable Parameters in Batch Files
     Loops in Batch Files
     Conditional Processing
     Chaining of Batch Files
     Subroutines for Batch Files
     COPY Command
     FIND Command

A)Loops in Batch Files

     There are several methods for creating loops in batch files. 
If you want the entire batch file to repeat, you can use the %0 
replaceable parameter as the last command. You will recall that 
%0 is always replaced with the file name of the batch file. When 
you add it asthe last statement in a batch file, it causes all of 
the commands in thefile to be repeated. For example, if you 
create a batch file namedDIRA.BAT that contains the command 
statements

	  ECHO OFF
	  ECHO Insert new disk in drive A
	  PAUSE
	  DIR A:/p
	  %0

the file will repeatedly prompt you to insert a different disk in 
drive A and then give you a directory listing of all of the files 
it contains when you press a key to continue. This batch file 
will continue to repeat until you press Ctrl-C or Ctrl-Break to 
terminate it.
    The FOR Loop

     To repeat a command within a batch file for a specific 
number of cases, you use the FOR command. The syntax for the FOR 
command is 

	  FOR %%variable IN (set) DO command

where

	  command	 Specifies the command to be executed for
			 each member listed in the (set)
                         argument, in the order in which these 
			 members are entered. The command
                         argument can consist of only a single 
                         command, which can be another batch file 
                         command (except for the FOR command), an 
                         executable program, batch file, or DOS 
                         command. Note that you cannot nest FOR 
			 batch commands, which is why the command
                         argument cannot contain another FOR 
                         command statement.
	  set		 Specifies files to be operated upon.
	  variable	 Specifies the variable to be operated on
			 by the command. Notice that a double
                         percent sign is entered before the 
                         variable (usually, though not 
                         necessarily, a single letter) to 
                         distinguish it from a replaceable 
                         parameter.

Consider this example using the FOR command:

	  FOR %%A IN (1985.WK1 1986.WK1 1987.WK1)
	  DO COPY %%A %2

In this batch file, the FOR command statement copies each of the 
three worksheet files listed in the (set) argument to the
directory path entered when the batch file is run by passing it 
to the %2 replaceable parameter. Notice that the command argument
in this example is actually COPY %%A, instead of just COPY.
    The GOTO Command

     You can also cause a batch file to execute (and sometimes 
repeat) a group of command statements in the file beginning at a 
specific point. To do this, you use the GOTO batch command. You 
indicate where in the batch file the commands are to be executed 
(or repeated) by using a label. 
     The syntax of the GOTO command is 

	  GOTO [:]label

where

	  label 	 Specifies a character string of up to
                         eight alphanumeric characters, and is 
                         not case-sensitive. By convention, 
                         alphabetic characters are entered in 
                         lowercase and the label name is prefaced 
                         by a colon. Note that the colon is 
                         mandatory before the actual label, but 
                         optional before the argument in the 
                         GOTO. The label, however, cannot contain 
                         a period (.).

     When you use the GOTO command, DOS executes all of the 
command statements listed below the label until it reaches the 
end of the batch file or another GOTO statement telling it to 
begin reprocessing the commands or to process a new set of 
commands beneath another label.
     Looping with the GOTO command can be illustrated by the 
following generalized form:

	  :label
	  command%1
	  .
	  .
	  .
	  command%n
	  SHIFT
	  GOTO :label

Assuming that the commands listed below the :label contain 
replaceable parameters, with the use of the SHIFT batch command, 
this loop would be executed indefinitely (until you terminated 
the batch file by pressing Ctrl-C or Ctrl-Break).

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
     Batch Files
     Creation of Batch Files
     AUTOEXEC.BAT File
     Displaying of Text with Batch Files
     ECHO batch file command
     Replaceable Parameters in Batch Files
     Loops in Batch Files
     Conditional Processing
     Chaining of Batch Files
     Subroutines for Batch Files

A)Conditional Processing

     The endless loop illustrated above is of limited use in 
batch files. It is much more common to use the GOTO command with 
conditional statements. That way, the commmands listed beneath 
the label are executed only when the condition is true. Using the 
GOTO command with conditions allows you to create batch files 
that branch according to the result of the condition.
     In addition to using conditional processing to branch, you 
can also have command statements executed only when there is 
equivalency between two items or if a particular file exists.
    The IF Command

     The batch IF command is used to allow conditional execution 
of command statements. The syntax of the IF command is as 
follows:

	  IF [NOT] condition command

If you wish to have branching occur as a result of the outcome of 
the condition, use this form:

	  IF [NOT] condition GOTO [:]label

     There is no ELSE command in the batch file command 
vocabulary. If you wish to have the program branch to one set of 
commands if the condition is true and another if it is false, use 
this form:

	  IF condition GOTO [:]labela
	  GOTO [:]labelb

If the condition is true, execution jumps to the commands beneath 
label a. If it is false, it jumps to those beneath label b. Note 
that you do not have to use the second GOTO statement if the 
commands to be executed when the condition is false follow the IF 
statement directly.

    Testing for Equivalence

     The condition argument in an IF command can test for
equivalence between two items. If they are found to be equivalent 
(that is, identical in terms of characters and case), then the 
command statement listed in the command argument is executed.
When you test for equivalence, you use a double equal sign. The 
syntax is as follows:

	  IF string1==string2 command

Note that strings are case-sensitive.
     For example, you could enter the following IF command:

	  IF %1==December GOTO :endofyr

If you execute this batch file and enter December as the first 
replaceable parameter, the batch file will jump to the label 
:endofyr and execute the commands that are listed beneath it.

    Testing for the Existence of a File

     You test for the existence of a particular file as the 
condition argument of the IF command. The syntax for this use is
as follows:

	  IF EXIST [d:][path]filename command

The options are as follows:

	  command	      Specifies a command to be executed
                              only when the file entered for the 
			      d:path filename argument is found
                              on the drive/directory indicated 
                              (if these parameters are omitted, 
                              then in the current directory). 
	  d:pathfilename      Specifies the file to be operated
                              on.

     For example, you might have this IF command statement in a 
batch file:

	  IF EXIST 4QTRTOTL GOTO :yrend

The commands beneath the :yrend label are executed only if DOS 
locates the file named 4QTRTOTL in the current directory. If this 
file is not found, this GOTO statement is ignored.

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
     Batch Files
     Creation of Batch Files
     AUTOEXEC.BAT File
     Displaying of Text with Batch Files
     ECHO batch file command
     Replaceable Parameters in Batch Files
     Loops in Batch Files
     Conditional Processing
     Chaining of Batch Files
     Subroutines for Batch Files

A)Chaining of Batch Files

     You can chain batch files by adding the name of the second 
batch file to be executed as the last statement in the command 
statements of the first batch file. Do not confuse chaining batch 
files with calling a new batch file as a subroutine. When 
chaining batch files, control does not return to the first batch 
file as when using subroutines (see the section on Using 
Subroutines, which follows). Because of this, reference to the 
second batch file must be entered as the last command statement 
in the first batch file. If it is not, the commands below this 
reference in the first file will never be executed.

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
     Batch Files
     Creation of Batch Files
     AUTOEXEC.BAT File
     Displaying of Text with Batch Files
     ECHO batch file command
     Replaceable Parameters in Batch Files
     Loops in Batch Files
     Conditional Processing
     Subroutines for Batch Files

A)Subroutines for Batch Files

     To execute a second batch file as a subroutine (that is, 
have control returned to the first batch file upon execution of 
all command statements in the second file), you must load a 
second copy of the command processor, using the COMMAND command. 
The syntax is

	  COMMAND /C batch

where

          /C             Tells DOS that this a secondary copy of 
                         the command processor. 
	  batch 	 Specifies the batch file you wish to
                         call as a subroutine.

     To have control return to the first batch file and to have 
the secondary copy of the command processor unloaded, the EXIT 
command must be the last statement in the batch file used as a 
subroutine. If you do not place EXIT as the last command 
statement in the called batch file, control will not return to 
the calling batch file and the secondary copy of the command 
processor will continue to run.
    Using The CALL Command

     DOS 3.3 has added a CALL command that allows you to call a 
second batch file as a subroutine (that is, execute the commands 
in a second batch file without terminating the first batch file). 
This command can be used in place of the COMMAND and EXIT 
commands. 
     The syntax of the CALL command is

	  CALL [d:][path]filename

where

	  d:pathfilename	   Specifies the name of the
                                   batch file to be called. When 
                                   entering this file name, do 
                                   not include the .BAT file 
                                   extension.

     You can use the CALL command to call its own batch file. 
However, you need to provide a method whereby the batch file is 
eventually terminated.

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
     Batch Files
     Creation of Batch Files
     AUTOEXEC.BAT File
     Displaying of Text with Batch Files
     ECHO batch file command
     Replaceable Parameters in Batch Files
     Loops in Batch Files
     Conditional Processing
     Chaining of Batch Files
     COMMAND Command

A)CONFIG.SYS File

     Each time you boot up your computer, DOS searches the root 
directory of the drive from which it was started for a file named 
CONFIG.SYS. If this file is located, DOS executes all of the 
commands it contains much like a batch file (although this file 
is executed long before an AUTOEXEC.BAT file), according to the 
values assigned by special configuration commands. If DOS does 
not find this file in the root directory, it supplies its own 
default values for all of the configuration commands it requires.
     The CONFIG.SYS file is used, then, only when you need to set 
new values for particular configuration commands. The parameters 
that can be modified in the CONFIG.SYS file include:

            þ  The BREAK status
            þ  The number of disk BUFFERS
            þ  The COUNTRY specification
            þ  Additional DEVICE drivers
            þ  The maximum number of drives that you may access 
               (LASTDRIVE)
            þ  The maximum number of files that can be open 
               concurrently by file handlers (FILES)
            þ  The maximum number of files that can be open 
               concurrently by file control blocks (FCBS)
            þ  The SHELL
            þ  Override the default stack resources (STACKS)

Each of these parameters is explained in this appendix, along 
with its associated commands.

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
     Creation of CONFIG.SYS File
     BREAK Status
     BUFFERS Parameter
     COUNTRY Parameter
     DATE Command
     Devices, Drivers for
     LASTDRIVE Parameter
     FCBS Parameter
     FILES Parameter
     SHELL Parameter
     STACKS Parameter

A)Creation of CONFIG.SYS File

     You can create the CONFIG.SYS file using the COPY command, 
EDLIN (the line editor supplied with DOS), or any other editor or 
word processor that can save its text in ASCII format. If you 
create it with a word processor, then save it in ASCII or text 
format and copy it to the root directory. To put the commands 
that you enter into commission, you must reboot your computer 
(Ctrl-Alt-Del, or turn the power off and on ).
     To create the CONFIG.SYS file using the COPY command, use 
the following model:

	  COPY CON CONFIG.SYS

Before creating a CONFIG.SYS file for a floppy or your hard disk, 
make sure that you are in the root directory (\) before you enter 
this command.
     After typing this command and pressing the Enter key, you 
simply type in each configuration command to be processed when 
the CONFIG.SYS file is executed. After typing in each command, 
you terminate the line by pressing the Enter key.
     Once you have entered all of the configuration command 
statements you wish to have in this file, you save it on disk (in 
the current directory) by pressing Ctrl-Z (you can also 
accomplish this by pressing F6 on IBM PCs and most compatibles) 
and the Enter key.

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
     CONFIG.SYS File
     BREAK Status
     BUFFERS Parameter
     COUNTRY Parameter
     Devices, Drivers for
     LASTDRIVE Parameter
     FCBS Parameter
     FILES Parameter
     SHELL Parameter
     STACKS Parameter


A)BREAK Status(B

     Normally, DOS checks for the BREAK key (Ctrl-Break) only 
when performing standard input/output or print operations because 
the default for the BREAK command is off. If you want DOS to 
check for the BREAK key under more circumstances, set the status 
to on by entering

	  BREAK = ON

as a line in the CONFIG.SYS file. Setting the status to on in 
this file will allow you to abort program operations that produce 
few or no standard device operations (such as running a 
compiler). For more information on the BREAK command, refer to 
its reference entry in the main text of the book.

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
     CONFIG.SYS File
     Creation of CONFIG.SYS File
     BUFFERS Parameter
     COUNTRY Parameter
     Devices, Drivers for
     ANSI.SYS
     LASTDRIVE Parameter
     FCBS Parameter
     FILES Parameter
     SHELL Parameter
     STACKS Parameter

A)BUFFERS Parameter

     A disk buffer is a specific block of RAM that DOS uses to 
store temporarily data that is being read or written to a disk. 
The default number of buffers maintained by DOS is 2. In version 
3.3, the number of buffers is set according to these criteria:

            þ  BUFFERS=3 if you have a disk drive whose capacity 
               is greater than 360K.
            þ  BUFFERS=5 if your computer has more than 128K RAM.
            þ  BUFFERS=10 if your computer has more than 256K 
               RAM.
            þ  BUFFERS=15 if your computer has more than 512K 
               RAM.

Only if none of these apply to your computer system is the 
default number of buffers set to 2. Each buffer that is added 
with the BUFFERS command uses up an additional 528 bytes of 
memory. 
     To open additional buffers, you use the BUFFERS command 
followed by the equal sign and the number of buffers to use in 
the CONFIG.SYS file. For example, to increase the number of 
buffers from 2 to 10, you would enter

	  BUFFERS = 10

in a line of the CONFIG.SYS file.
     Generally, performance is enhanced when running application 
programs when you increase the number of buffers from the default 
of 2. However, there is a trade-off that can occur when you have 
somewhere between 10 and 20 buffers open (depending upon the type 
of application that you are using). At that point, it may take 
DOS as much time to locate data in a particular memory buffer as 
it would to get the data from disk.
     Many DOS application programs, such as WordStar 2000 and 
dBASE III PLUS, require many more than 2 buffers in order to run. 
During installation of such software, the application's 
installation program checks the root directory to make sure first 
that the CONFIG.SYS exists and, if it does, to check the number 
of buffers open with the BUFFERS command. If the number is less 
than 20 (or the BUFFER command is not used in the file), the 
program will then automatically enter a BUFFERS command or edit 
an existing one to read as follows:

	  BUFFERS = 20

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
     CONFIG.SYS File
     Creation of CONFIG.SYS File
     BREAK Status
     COUNTRY Parameter
     Devices, Drivers for
     LASTDRIVE Parameter
     FCBS Parameter
     FILES Parameter
     SHELL Parameter
     SELECT Command
     STACKS Parameter

A)COUNTRY Parameter

     You can use the COUNTRY command in a CONFIG.SYS file to 
change the currency, date, or time format or the collating 
sequence to match that preferred by a foreign country. The syntax 
of the COUNTRY command is

	  COUNTRY = xxx,[yyy],[d:]COUNTRY.SYS

where

	  xxx	    Specifies the country code (see SELECT).
	  yyy	    Specifies the code page of the desired
                    country (in DOS 3.3, a country may have 
                    different information depending on the code 
                    page selected- -see Appendix C of the DOS 
                    reference for a listing of the codes).

     Note that if you have used the SELECT command, DOS will have 
already created a CONFIG.SYS file that includes the COUNTRY 
configuration command. To make changes to the COUNTRY codes, you 
must then edit the contents of this file using either EDLIN or a 
word processor that can read ASCII files.

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
     CONFIG.SYS File
     Creation of CONFIG.SYS File
     BREAK Status
     BUFFERS Parameter
     Devices, Drivers for
     LASTDRIVE Parameter
     FCBS Parameter
     FILES Parameter
     SHELL Parameter
     STACKS Parameter

A)Devices, Drivers for

     DOS automatically loads device drivers for standard 
input/output devices, printers, and storage devices such as 
floppy and fixed disk drives. Therefore, you need to use the 
DEVICE configuration command in the CONFIG.SYS file only when you 
need to install additional nonstandard devices (such as a mouse 
or an 8-inch floppy disk drive). The driver files for nonstandard 
devices are supplied by the device manufacturer.
     To install a new device driver, you enter the DEVICE command 
followed by the equal sign and the name of the file that contains 
the driver on a line in the CONFIG.SYS file. 
     The DOS diskette includes two device drivers, ANSI.SYS and 
VDISK.SYS. Version 3.3 has added three more device 
drivers:DISPLAY.SYS, PRINTER.SYS, and DRIVER.SYS.
    ANSI.SYS

     The ANSI.SYS driver file extends cursor control and keyboard 
reassignments. These extended functions make it easier for 
software to control cursor positioning, display messages on the 
screen, set colors, and reassign keyboard functions. Some 
software applications, such as SuperKey, require that ANSI.SYS be 
loaded by theCONFIG.SYS file in order to run.
     To add this driver, you enter

	  DEVICE = [d:][path]ANSI.SYS

on a line of your CONFIG.SYS file, where

	  d:path    Specifies the drive and path.
    VDISK.SYS

     The VDISK.SYS driver allows you to set up a virtual or RAM 
disk that performs the functions of a physical disk drive. A 
virtualdisk, however, is installed in RAM and, therefore, 
disappears when power is interrupted to the computer system. You 
can install more than one virtual disk using the VDISK.SYS 
driver, depending upon the amount of RAM available to your 
system.
     The syntax of the DEVICE configuration command when using 
the VDISK.SYS driver is as follows:

	  DEVICE = [d:][path]VDISK.SYS [comment][bbb]
	  [comment][sss][comment][ddd][/E[:m]]

     Before explaining each optional parameter, consider the 
following example that uses all of the options:

	  DEVICE = C:\DOS\VDISK.SYS buffer size=256
	  sector size=512 directory entries=128 /E

The options are as follows:

	  d:path	 Tells DOS where the VDISK.SYS file is
                         located (C:\DOS in the example).
	  bbb		 Sets the size of the virtual disk in
                         kilobytes. If you do not specify this 
                         parameter, DOS uses a default of 64K. 
                         You can enter a value between 1K and the 
                         amount of memory available to your 
                         computer. Notice that you can also add 
			 an optional [comment] explaining the
                         value. In the example, the comment 
			 buffer size= precedes the value in
                         kilobytes.
	  sss		 Sets the sector size in bytes. The
                         default of 128 bytes is used by DOS if 
                         this parameter is omitted or an 
                         inaccurate value is entered. Allowable 
                         values for the sector size are 128, 256, 
                         or 512 bytes. The sector size parameter 
                         can also be preceded by an optional 
                         comment. In the example, the comment 
			 sector size= has been added.
	  ddd		 Sets the number of directory entries
                         that the virtual disk can hold (one 
                         directory entry per file copied to the 
                         virtual disk). The default is 64, and 
                         you can enter a value between 2 and 512. 
                         However, DOS may automatically adjust 
                         the value you enter when installing the 
                         virtual disk. The value is increased to 
                         the nearest sector boundary (as set by 
                         the sector size). It is decreased if the 
                         size of the virtual disk (as set by the 
                         buffer size) is too small to accommodate 
                         the file allocation table, the 
                         directory, and two additional sectors. 
                         If the directory size reaches 1 and 
                         these files still cannot be 
                         accommodated, you will receive an error 
                         message and the virtual disk will not be 
                         installed.
	  comment	 You may enter an optional comment before
			 the [ddd] parameter. In the example, the
			 comment directory entries= has been
                         added.
          /E             Tells DOS to install the virtual disk in 
			 extended memory AM at or beyond 1
                         megabyte). This parameter can only be 
                         used with a personal computer that has 
                         extended memory, such as the IBM PC AT 
                         or PS/2 machines (computers equipped 
                         with an add-on board such as the Intel 
                         Above Board support expanded instead of 
                         extended memory). When you add the /E 
                         parameter, the virtual disk buffer is 
                         established in extended memory while the 
                         device driver is installed in 
                         conventional memory. Extended memory up 
                         to 4 megabytes may be used for a single 
                         virtual disk.
	  :m		 Specifies the maximum number of sectors
			 (as specified by the sss parameter) of
                         data that are transferred to the virtual 
                         disk at one time. The permissible values 
                         are 1 through 8, with 8 being the 
                         default value.

     When a virtual disk is established in extended memory, 
interrupt servicing is suspended during data transfers. In some 
situations, this can result in some interrupts being lost. If 
this happens, you should install the virtual disk in conventional 
memory. If the problem is resolved, you can then resinstall the 
virtual disk in extended memory with a smaller [:m] value.
     When you establish a virtual disk, DOS assigns it the next 
available drive letter specification. For example, if your 
computer has two floppy disk drives, A and B, the virtual disk 
will be given C as the drive letter specification. If you have a 
single fixed disk, C, the virtual disk will be given D as the 
drive letter specification.
    DISPLAY.SYS

     The DISPLAY.SYS device driver allows you to use code page 
switching on the EGA and IBM PS/2 displays and the IBM 
Convertible LCD screen. This device driver is included only in 
version 3.3 of DOS, which supports code page switching (see the 
CHCP and NLSFUNC command reference entries), and it is used only 
when you need to switch from the standard for U.S. symbols to new 
code pages containing international symbols. 
     The syntax of the DISPLAY.SYS DEVICE configuration command 
is as follows:

	  DEVICE = [d:][path]DISPLAY.SYS CON[:]=
	  (type[,[hwcp][,(n,m)]])

The options are as follows:

	  d:path    Specifies the drive letter and path that
                    contain the DISPLAY.SYS file.
	  type	    Specifies the display adapter type. You can
                    use MONO, CGA, EGA, and LCD. Use EGA if you 
                    have an IBM PS/2 display (VGA is not yet 
                    fully supported).
	  hwcp	    Specifies the code page. Permissible values
                    are 437, 850, 860, 863, and 865 (refer to 
                    Appendix C of the DOS documentation for a 
                    description of these code page values).
	  n	    Specifies the number of prepared code pages
                    that can be supported. This must be a value 
                    between 0 and 12 (refer to the table in the 
                    DOS documentation for the DISPLAY.SYS command 
                    to determine this value).
	  m	    Specifies the number of subfonts supported by
                    each code page (refer to the table in the DOS 
                    documentation for the DISPLAY.SYS command to 
                    determine this value).

Note that if you are using ANSI.SYS with DISPLAY.SYS, the DEVICE 
= ANSI.SYS statement must precede the configuration statement 
DEVICE = DISPLAY.SYS in the CONFIG.SYS file.
    PRINTER.SYS

     The PRINTER.SYS device driver allows you to use code page 
switching on the IBM Proprinter Model 4201 and the IBM 
Quietwriter III Model 5202. Like the DISPLAY.SYS file, this 
device driver is included only in version 3.3 of DOS, which 
supports code page switching (see the CHCP and NLSFUNC command 
reference entries), and it is used only when you need to switch 
from the standard for U.S. symbols to new code pages containing 
international symbols.
     The syntax of the PRINTER.SYS DEVICE configuration command 
is as follows:

	  DEVICE = [d:][path]PRINTER.SYS LPT#[:]=
	  (type[,[(hwcp1,hwcp2,...)][,n,]])

The options are as follows:

	  d:path	      Specifies the drive letter and path
                              that contain the PRINTER.SYS file.
	  LPT#		      Specifies the printer device. It
                              can be entered up to three times 
                              (for LPT1, LPT2, and LPT3). You can 
                              substitute PRN for LPT in the 
                              command line.
	  type		      Specifies the type of printer use.
                              You can choose between 4201 (IBM 
                              Proprinter) or 5202 (IBM 
                              Quietwriter III). 
	  (hwcp1,hwcp2,...)   Specifies the code page that is
                              built into the hardware. The 
                              permissible values are 437, 850, 
                              860, 863, and 865 (refer to the 
                              PRINTER.SYS command in the DOS 
                              documentation for an explanation of 
                              how these code page values are 
                              applied to the two printer types).
	  n		      Specifies the number of additional
                              code pages that can be prepared. 
                              This value determines the number of 
                              buffers that PRINTER.SYS will set 
                              up to hold the code pages being 
                              prepared. The maximum number that 
                              can be specified is 12.
    DRIVER.SYS

     The DRIVER.SYS statement in the CONFIG.SYS file allows you 
to access and use a disk device by referring to a logical drive 
letter. The syntax used when adding this to the CONFIG.SYS file 
isas follows:

	  DEVICE = DRIVER.SYS /D:ddd[/T:ttt][/S:ss][/H:hh]
	  [/C][/N][/F:f]

The options are as follows:

	  /D:ddd    Specifies the physical drive number between 0
                    and 255. The first physical diskette drive 
                    (drive A) has the value 0. The second 
                    physical diskette drive (drive B) has the 
                    value 1. The third physical diskette drive 
                    (must be external) has the value 2. The first 
                    fixed drive has the value 128 and the second 
                    has the value 129.
	  /T:ttt    Specifies the number of tracks per side
                    between 1 and 999 (default: 80).
	  /S:ss     Specifies the number of sectors per track
                    between 1 and 99 (default: 9).
	  /H:hh     Specifies the number of drive heads between 1
                    and 99 (default: 2).
          /C        Specifies that changeline support is required 
                    (only used on computers such as the IBM PC AT 
                    that support diskette changeline).
          /N        Specifies that the physical device is a non-
                    removable block device (such as a fixed 
                    disk).
	  /F:f	    Specifies the device type (form factor). The
		    value of the f parameter is determined as
                    follows:
		    Device		Value
		    160K/180K		0
                    320K/360K           0
                    1.2 megabytes       1
                    720K or others      2
                    1.44 megabytes      7

     Note that the DEVICE=DRIVER.SYS configuration statement is 
not used to drive fixed (hard) disks. To set a logical drive 
letter for a fixed disk, use the SUBST command (see the SUBST 
reference entry for more information).
     To find out the logical drive letter assigned by DOS to the 
device driver for a particular computer configuration and value 
of /D:, refer to the table included in the DOS documentation 
under the reference entry for the DEVICE command.

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
     CONFIG.SYS File
     Creation of CONFIG.SYS File
     BREAK Status
     BUFFERS Parameter
     COUNTRY Parameter
     LASTDRIVE Parameter
     FCBS Parameter
     FILES Parameter
     SHELL Parameter
     STACKS Parameter

A)LASTDRIVE Parameter

     The highest drive specification letter that DOS 3 will 
recognize is drive E (three fixed drives attached: C, D, and E). 
If your system has more than this number of logical or physical 
drives attached, you must add a LASTDRIVE statement to your 
CONFIG.SYS file:

	  LASTDRIVE = x

where

	  x    Specifies a letter between A and Z. If the drive
               letter you specify is less than the number of 
               drives attached to your system, DOS will ignore 
               the LASTDRIVE statement in the CONFIG.SYS file.

     For example, if you are on a network and you have 15 drive 
volumes attached to the system, you would enter

	  LASTDRIVE = O

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
     CONFIG.SYS File
     Creation of CONFIG.SYS File
     BREAK Status
     BUFFERS Parameter
     COUNTRY Parameter
     Devices, Drivers for
     FCBS Parameter
     FILES Parameter
     SHELL Parameter
     STACKS Parameter

A)FCBS Parameter

     Some older application programs use file control blocks 
(FCBs) instead of the newer file handles to create, open, and 
delete files as well as to read from and write to files. When 
using these programs on a network with file sharing in use, you 
may have to increase the number of files that can be opened by 
FCBs. The default value used by DOS is 4 files.
     To specify a new number of files that can be concurrently 
open by DOS, you use the FCBS command in the CONFIG.SYS file:

	  FCBS = x,y

where

	  x	    Specifies the total number of files that can
                    be opened by FCBs.
	  y	    Specifies the number of files protected from
                    automatic closure by DOS (the default is 0).

     When file sharing is in use and an application program tries 
to open more than the total number of files, DOS closes the 
least-recently used file and opens the new file (excluding the 
files protected from automatic closure). If the program tries to 
read from or write to a file that has been closed by DOS, you 
will receive the following error message:

	  FCB unavailable
	  Abort, Fail?

     To avoid such an error, you would add a FCBS command to your 
CONFIG.SYS file. For example, entering

	  FCBS = 10,5

would allow 10 FCB files to be open concurrently and would 
protect 5 of these from automatic closure. 
     When specifying the first parameter (the total number of FCB 
files), you can enter a value between 1 and 255. When specifying 
the second parameter (the number of files protected from 
automatic closure), you can enter a value between 0 and 255. (See 
also the SHARE command in the main text.)

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
     CONFIG.SYS File
     Creation of CONFIG.SYS File
     BREAK Status
     BUFFERS Parameter
     COUNTRY Parameter
     Devices, Drivers for
     LASTDRIVE Parameter
     FILES Parameter
     SHARE Command
     SHELL Parameter
     STACKS Parameter

A)FILES Parameter

     By default, DOS allows up to 8 files (controlled by file 
handles, not FCBs) to be open concurrently. This number is 
insufficient to run several newer application programs as well as 
some DOS commands (such as XCOPY). 
     If you receive either the error message

	  Too many open files

or

	  Too many files open

you will have to use the FILES configuration command in the 
CONFIG.SYS file to increase the maximum number of files available 
to the entire system:

	  FILES = n

where

	  n	    Specifies the number of files that can be
                    opened at the same time (a value between 8 
                    and 255). However, be aware that the maximum 
                    number of files that a single process can 
                    have opened is set at 20.

To accommodate 15 different files being open at one time, you 
would enter

	  FILES = 15

as a line in the CONFIG.SYS file.

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
     CONFIG.SYS File
     Creation of CONFIG.SYS File
     BREAK Status
     BUFFERS Parameter
     COUNTRY Parameter
     Devices, Drivers for
     LASTDRIVE Parameter
     FCBS Parameter
     SHELL Parameter
     STACKS Parameter
     XCOPY Command

A)SHELL Parameter

     Normally, DOS loads the command processor from the 
COMMAND.COM file during the boot sequence. If you have your own 
command processor, you can have it initialized and loaded at 
start-up in place of COMMAND.COM by using the SHELL configuration 
command.
     The syntax of the SHELL command is

	  SHELL = [d:][path]filename [/E:xxxxx][/P]

where

	  d:pathfilename      Specifies the file name of the new
                              command processor (including its 
                              path, if it is not located in the 
                              root directory). Using COM-MAND.COM 
                              as the file name is a convenient 
                              way to increase the environment 
                              size under DOS 3.2 and 3.3.
	  /E:xxxxx	      Specifies the number of bytes for
                              the environment size (expressed as 
                              a base-10 integer between 160 and 
                              32768). 
          /P                  Causes COMMAND.COM to remain loaded 
                              and to execute the AUTOEXEC.BAT 
                              file (if one exists).

     Note that using the SHELL command to run a different command 
processor does not affect the COMSPEC command, which points to 
the name of the controlling processor (see SET in the reference 
entries). If you use the SHELL command in the CONFIG.SYS file to 
load a new command processor, you will also want to use the 
COMSPEC parameter in the SET command in the AUTOEXEC.BAT file to 
refer to it.

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
     CONFIG.SYS File
     Creation of CONFIG.SYS File
     BREAK Status
     BUFFERS Parameter
     COUNTRY Parameter
     Devices, Drivers for
     LASTDRIVE Parameter
     FCBS Parameter
     FILES Parameter
     STACKS Parameter

A)STACKS Parameter

     DOS 3.3 includes a STACKS configuration command that allows 
you to override the default stack resources used by DOS. The 
syntax of this command is

	  STACKS = n,s

where

	  n	    Specifies the number of stack frames between
                    8 and 64.
	  s	    Specifies the size in bytes of each stack
                    frame between 32 and 512.

     If the STACKS command is not included in the CONFIG.SYS 
file, the n and s parameters are set to 0 for the IBM PC, IBM PC
XT, and the IBM Portable PC. For all other IBM personal 
computers, the default values are n = 9 and s = 128.
     Every time a hardware interrupt occurs, DOS appropriates one 
stack frame from the stack pool. Once the interrupt has been 
processed, DOS returns the stack frame to the pool. If you 
experience stack overflow errors, you should use the STACKS 
command to increase the number of stack frames available to DOS.

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
     CONFIG.SYS File
     Creation of CONFIG.SYS File
     BREAK Status
     BUFFERS Parameter
     COUNTRY Parameter
     Devices, Drivers for
     LASTDRIVE Parameter
     FCBS Parameter
     FILES Parameter
     SHELL Parameter

A)Hard Disk Partitions

     Hard disks are usually so large that they can contain more 
than one type of operating system. For example, you can have DOS 
3.3 manage one part of a disk and UNIX manage another. Each of 
these sections is called a partition. You can have from one to
four partitions on a disk.
     Partitions are used to make the hard disk, especially a very 
large one, a more economical investment. They allow you to 
effectively have up to four completely different computer systems 
resident in one set of hardware. However, since they do not share 
a common software environment, they cannot share data directly. 
     Two types of partitions can be set up for DOS: a primary DOS
partition and an extended DOS partition. The primary DOS
partition is the partition that contains DOS and is the first 
partition on the disk. This is the only partition that must be on 
the disk if your disk is no larger than 32 megabytes. The 
extended DOS partition is a separate partition that cannot be 
used for booting, but can be divided into separate logical 
drives. 
     If you have more than 32 megabytes available on one hard 
disk, you will need to create an extended DOS partition, which is 
assigned the next logical drive letter. For example, if you had a 
60-megabyte hard disk drive, and wanted access to all of it, you 
would create a 32-megabyte primary partition and a 28-megabyte 
extended partition. The primary partition could be accessed as 
drive C, while the extended partition would be called drive D. 
You could also subdivide the extended partition into more logical 
drives (up to the letter Z).
     You must create partitions before using a hard disk drive. 
You will probably take the easiest route by simply making the 
entire disk into one primary partition. The FDISK program 
presented here, however, is necessary in several more advanced 
situations. For example, you may plan on using multiple operating 
systems from the same disk. FDISK will let you set up unique 
partitions for each system. (Each of these would be a primary 
partition, but only one could be designated the active partition, 
the one that will gain control at boot up.) Then again, you may 
be using one of the large hard disks (40 to 70 megabytes) that 
are increasingly common. Since DOS can only access a logical 
drive of 32 megabyte or less, you'll need to partition a larger 
physical drive into multiple logical drives. Only in this way can 
you store and retrieve information on the larger hard disk.
     Note: If your disk is already being used and you wish to
make a new partition, you will have to first back up all of your 
data and then run FDISK from a system diskette. Finally, you'll 
need to reformat your disk before restoring your files to it.

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
Configuration of DOS Partitions
Active Partitions, Changing of
Displaying of Partition Information
Deletion of DOS Disk Partitions

A)Configuration of DOS Partitions

     In this section, you will see exactly how to use the FDISK 
command. This procedure is very important, and it can have 
serious consequences if done incorrectly. However, it can also 
make your system more efficient, when done properly. FDISK is 
only usable on hard disk systems.
     Invoking the FDISK command is as simple as typing

	  FDISK

and pressing Return. emember to have your path set properly to
include the directory containing the FDISK command file.) After 
this command creates the appropriate partition(s), you must then 
logically format the disk.
     Warning: All data on your disk will be destroyed when you
create partitions with FDISK.
     When you first execute FDISK, the screen will clear and the 
FDISK Options screen will appear. This contains the menu used to 
get around in FDISK, as shown in the screen below.
----------------------------------------------------------------

     FDISK Options

     Current Fixed Disk Drive: 1

     Choose one of the following:

	  1.  Create DOS partition
	  2.  Change Active Partition
	  3.  Delete DOS partition
	  4.  Display Partition Information

     Enter choice: [1]

     Press ESC to return to DOS
----------------------------------------------------------------
     As you can see, there are four choices. If you have a system 
with more than one hard disk drive, the number in the Current
Fixed Disk Drive: 1 line would be changed to the number of drives
in your system. Also, a fifth option, Select Next Fixed Disk
Drive, would be displayed on the screen. You can work on only one
hard disk drive at a time, but you can switch from the drive you 
are working on to another drive. For now, let's assume you have 
one hard disk drive and that the screen below is what you see.
    Creating a Partition

     The first option on the FDISK Options menu is to create a 
DOS partition. Since you are using DOS, and not another operating 
system such as UNIX, you can only create DOS partitions. Should 
you wish to put another operating system onto the disk, that 
system would have its own version of FDISK and could then create 
its own partitions next to DOS'.
     Tip: If you plan to use your hard disk to support another
operating system, do not partition the whole disk. Leave some 
room so that another system can be loaded onto the disk.
     Choosing the first option to create a DOS partition results 
in the screen below. 
----------------------------------------------------------------
     Create DOS Partition

     Current Fixed Disk Drive: 1

	  1.  Create Primary DOS partition
	  2.  Create Extended DOS partition


     Enter Choice: [1]


     Press ESC to return to FDISK Options
----------------------------------------------------------------
     If you select option 2 at this point, intending to create an 
extended DOS partition before creating a primary partition, DOS
will display a message indicating that you cannot do so, and will 
suggest that you press Esc to return to the main FDISK Options 
menu. Assuming you are starting from scratch, you would select 
choice 1 to create the primary DOS partition. You will then see 
the screen shown below.
----------------------------------------------------------------
     Create Primary DOS Partition

     Current Fixed Disk Drive: 1

     Do you wish to use the maximum size
     for a DOS partition and make the DOS
     partition active (Y/N).........? [n]



     Press ESC to return to FDISK Options
----------------------------------------------------------------
     If you want to use the whole disk for DOS, then you answer Y 
on this screen. Doing so makes DOS use the whole disk. The 
computer will allocate the entire disk, and then come back with 
the message

	  System will now restart

	  Insert DOS diskette in drive A:
	  Press any key when ready . . .

Since you just created the partition, there is still nothing on 
the hard disk. The system must be rebooted from the disk drive. 
You can now format the entire hard disk just as you would a 
floppy diskette.
     If you answer N, you have the opportunity to create a 
smaller partition, as shown in the screen below. As you can see, 
there are 305 cylinders available on the total disk. A hard disk
consists of several platters, similar to a diskette; each platter 
consists of a series of concentric tracks made up of sectors. 
Each platter lies above another and is read by a different disk 
head. Viewed vertically, a series of tracks (with the same track 
number, but on different platters) located one above the other 
constitute a cylinder. The brackets in the screen shown below 
indicate the place where you may enter a number for cylinders 
that is less than the default maximum (305 on this disk).
----------------------------------------------------------------
     Create Primary DOS Partition

     Current Fixed Disk Drive: 1



     Total disk space is 305 cylinders.
     Maximum space available for partition
     is 305 cylinders.

     Enter partition size...........: [ 200]


     No partitions defined

     Press ESC to return to FDISK Options
----------------------------------------------------------------

     Notice that the second-to-last line on the screen tells you 
that no partitions have been defined yet. If you are using your 
disk for DOS alone, you should accept the default maximum 
cylinder value. All disk space will then be available for DOS and 
your DOS files. If you plan on splitting up your disk between DOS 
and another operating system, however, you'll have to decide for 
yourself what percentage of total disk space is needed for the 
other operating system. In this example, you intend to create an 
extended DOS partition, so 200 was entered for the number of 
cylinders in the primary DOS partition.
     Entering 200 results in the screen shown below. This screen 
tells you that the first partition on drive C is a primary DOS 
partition (PRI DOS) that starts at cylinder 0 and ends at 
cylinder 199, constituting a total of 200 cylinders. 
----------------------------------------------------------------
     Create Primary DOS Partition

     Current Fixed Disk Drive: 1

     Partition Status    Type   Start    End   Size
      C:  1             PRI DOS     0    199    200




     Primary DOS partition created

     Press ESC to return to FDISK Options
----------------------------------------------------------------
     Pressing Esc at this point returns you to the FDISK Options 
menu. If you again try to create a primary partition, DOS will 
show the following message on your screen:

	  Primary DOS partition already exists.
	  Press ESC to return to FDISK Options

     Note: There can only be one primary DOS partition. When DOS
boots up, the system files from this partition are loaded into 
memory for your operations. In this example, you have only used 
200 cylinders out of a possible 305, so you can make an extended 
DOS partition. To do so, you select choice 1 (create a DOS 
partition) on the FDISK Options menu and then select choice 2 
(create Extended DOS partition) on the Create DOS Partition menu.
     The resulting screen, shown below, allows you to create an 
extended DOS partition. This screen tells you the current 
partition information- -that is, that there are 305 total 
cylinders available for use- -and also tells you that 105 
cylinders remain unused. The 105 value is used as the default 
entry at this stage. You only need to type in a number over the 
105 to override the default. In the screen below, 55 was entered 
for the desired extended DOS partition, leaving 50 cylinders 
unused on the disk for another operating system.
----------------------------------------------------------------
     Create Extended DOS Partition

     Current Fixed Disk Drive: 1

     Partition Status    Type   Start   End   Size
      C: 1             PRI DOS      0   199   200


     Total disk space is 305 cylinders.
     Maximum space available for partition
     is 105 cylinders.

     Enter partition size............: [ 55]


     Press ESC to return to FDISK Options
----------------------------------------------------------------
     The screen will now clear, redisplay the partition 
information (including that on the new extended DOS partition), 
and print the message

	  Extended DOS Partition created
	  Press ESC to return to FDISK Options

near the bottom of the screen. Pressing Esc will result in the 
next step of the process (see screen below).
----------------------------------------------------------------
     Create Logical DOS Drive(s)



     No logical drives defined


     Total partition sized is	55 cylinders.

     Maximum space available for logical
     drive is	55 cylinders.

     Enter logical drive size..........:  [  45]


     Press ESC to return to FDISK Options
----------------------------------------------------------------
     Since you have just created an extended DOS partition, DOS 
wants to know if you want to create logical drives within this 
new partition. It tells you the total available cylinders in the 
partition and asks you to enter a size for the logical drive. In 
this example, you enter 45. The resulting screen will contain the 
logical drive information (drive name, starting cylinder, ending 
cylinder, and total cylinders used). 
     Suppose you wanted to create another logical drive, E, using 
the remaining ten cylinders. You could again choose option 1 on 
the FDISK Options menu. You would go again to the Create DOS 
Partition menu, but there would be one new choice displayed:

	  3. Create logical DOS drive(s) in
               the Extended DOS partition

This would bring you back to the screen for defining logical 
drives, where you could then enter the information for drive E. 
Going through this same sequence again in order to use the 
remaining ten cylinders will result in the screen below. Notice 
that the cylinder numbers are within the bounds of the extended 
DOS partition. You are told that DOS created two logical drives, 
D and E, with sizes of 45 and 10 cylinders. Furthermore, you're 
reminded that no more available space remains for any other 
logical drives. Press Esc, and you will once again be back at the 
FDISK Options menu.
----------------------------------------------------------------
     Create Logical DOS Drive(s)

     Drv  Start   End	Size
      D:    200   244	  45
      E:    245   254	  10




     All available space in the Extended DOS
     partition is assigned to logical drives.

     Logical DOS drive created, drive letters 
     changed or added
     Press ESC to return to FDISK Options
----------------------------------------------------------------
     If you try to create another extended partition, you will 
get a partition information screen and the message

	  Extended DOS partition already exists.
	  Press ESC to return to FDISK Options

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
Active Partitions, Changing of
Deletion of DOS Disk Partitions
Displaying of Partition Information
FDISK Command
Hard Disk Partitions

A)Active Partitions, Changing of

     The active partition is the partition that is used to boot
the system. It is the default partition. Choosing option 2 on the 
main FDISK Options menu leads you to a menu like that shown in 
the screen below, in which the partition information is displayed 
along with the total number of cylinders available on the disk. 
FDISK now wants to know the number of the partition that you wish 
to make active.
----------------------------------------------------------------
     Change Active Partition

     Current Fixed Disk Drive: 1

     Partition Status   Type   Start   End   Size
      C: 1            PRI DOS      0   199   200
         2            EXT DOS    200   254    55

     Total disk space if  305 cylinders.

     Enter the number of the partition you
     want to make active.............: [2]

     Partition selected (2) is not bootable,
     active partition not changed.
     Press ESC to return to FDISK Options
----------------------------------------------------------------
     If you enter the number 2, as shown in the figure, DOS will 
inform you that only the primary DOS partition (1) may be made 
active. Type the number 1 so that the primary DOS partition will 
have control when the system comes up. Pressing Return will 
result in the adjusted partition information display seen below.
----------------------------------------------------------------
     Change Active Partition

     Current Fixed Disk Drive: 1

     Partition Status   Type   Start   End   Size
      C: 1        A   PRI DOS      0   199    200
         2            EXT DOS    200   254     55


     Total disk space is  305 cylinders.



     Partition 1 made active

     Press ESC to return to FDISK Options
----------------------------------------------------------------
     Notice the letter A on the first line of this display. An A 
under Status tells you that partition 1 is the active partition.
Pressing Esc takes you back to the FDISK Options menu. 

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
Configuration of DOS Partitions
Deletion of DOS Disk Partitions
Displaying of Partition Information
FDISK Command
Hard Disk Partitions

A)Displaying of Partition Information

     Option 4 on the FDISK Options menu is used to display 
information about the partitions. This is useful because no extra 
functions will be executed at the same time; you can simply look 
at the information. Choosing option 4 yields the screen shown 
below.
----------------------------------------------------------------
     Display Partition Information

     Current Fixed Disk Drive: 1

     Partition Status   Type   Start   End   Size
      C: 1        A   PRI DOS      0   199    200
         2            EXT DOS    200   254     55


     Total disk space is   305 cylinders.

     The Extended DOS partition contains
     logical DOS drives. Do you want to
     display logical drive information?  [Y]

     Press ESC to return to FDISK Options
----------------------------------------------------------------
     The information at the top of the screen is familiar by now. 
But what if you want to see information about the logical drives 
that have been defined? Look at the bottom half of the screen, 
where you are asked if you want to see this information. Replying 
with Y results in a display of information about these logical 
drives (see the screen below). Pressing Esc at this point will 
return you to the FDISK Options menu.
----------------------------------------------------------------
     Display Logical DOS Drive Information

     Drv   Start   End	 Size
     D:      200   244	   45
     E:      245   254	   10






     Press ESC to return to FDISK Options
----------------------------------------------------------------

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
Active Partitions, Changing of
Configuration of DOS Partitions
Deletion of DOS Disk Partitions
FDISK Command
Hard Disk Partitions

A)Deletion of DOS Disk Partitions

     As with most things, what DOS giveth, DOS can taketh away- -
with a little prodding from you. Selecting choice 3 on the FDISK 
Options menu produces the Delete DOS Partition menu, shown below.
----------------------------------------------------------------
     Delete DOS Partition

     Current Fixed Disk Drive: 1

     Choose one of the following:

	  1.  Delete Primary DOS partitions
	  2.  Delete Extended DOS partition
	  3.  Delete logical DOS drive(s) in
                  the Extended DOS Partition


     Enter choice: [ ]


     Press ESC to return to FDISK Options
----------------------------------------------------------------
     Using this menu, you can delete any of the information 
you've already set up. You may want to expand or contract other 
partitions, or you may no longer want to use a partition in the 
manner you originally designed. In any case, you can only make 
changes in a certain order. You cannot delete the primary DOS 
partition without first deleting the extended DOS partition. If 
you try, DOS will give you this message:

	  Cannot delete Primary DOS partition on
	  drive 1 when Extended partition exists

	  Press ESC to return to FDISK Options

     In addition, you cannot delete an extended DOS partition 
without first ``undefining'' (deleting) the logical drives in 
that partition. Trying to delete the extended DOS partition 
before deleting the drives in it will simply display the current 
partition information with the patient message

	  Cannot delete Extended DOS partition
	  while logical drives exist.
	  Press ESC to return to FDISK options

     Choice 3 in the Delete DOS Partition menu is probably the 
first selection you will need to make; you work your way 
backwards through the order in which you created things. 
ctually, you will find that this is a fairly natural process.)
Selecting choice 3 produces the screen shown below, which 
contains the logical drive information and the size of the 
extended DOS partition the drives are in. You are also warned 
that any data contained in the logical disk drive to be deleted 
will also be deleted. If you still want to delete the drive, 
simply enter the drive identifier. You will then be asked to 
confirm this step. In the screen below, you have selected drive E 
to delete first, and confirmed the choice by typing Y. If you had 
entered N, you would have been returned to the FDISK Options 
menu.
----------------------------------------------------------------
     Delete Logical DOS Drive

     Drv   Start   End	 Size
      D:    200    244	   45
      E:    245    254	   10


     Total partition size is   55 cylinders.

     Warning! Data in the logical DOS drive
     will be lost. What drive do you wish
     to delete.........................? [e]

     Are you sure......................? [y]

     Press ESC to return to FDISK Options
----------------------------------------------------------------
     Once FDISK deletes the logical drive, it updates the display 
at the top of the screen and asks for another drive to delete. If 
you wanted to regain all the space used by this partition, you 
would then enter drive D, confirm your entry, and end up with the 
screen shown below. Pressing Esc twice at this point would 
bring you back up through the menu screens to the main FDISK 
Options menu.
----------------------------------------------------------------
     Delete Logical DOS Drive

     Drv   Start   End	 Size
	D: drive deleted
	E: drive deleted




     Total partition size is  55 cylinders.
     All logical drives deleted in the
     Extended DOS partition



     Press ESC to return to FDISK Options
----------------------------------------------------------------
     Now that the logical drives are gone, you can delete the 
extended DOS partition itself if you choose to do so. Choosing 
option 2 on the Delete DOS Partition menu results in the familiar 
form of an FDISK screen (see below). Again, you are shown the 
partition information display, warned that data will be lost, and 
asked if you really want to delete the extended DOS partition. 
----------------------------------------------------------------
     Delete Extended DOS Partition

     Current Fixed Disk Drive: 1

     Partition Status   Type   Start   End   Size
      C: 1        A    PRI DOS     0   199    200
         2             EXT DOS   200   254     55



     Warning! Data in the Extended DOS
     partition will be lost. Do you wish
     to continue.......................?  [y]


     Press ESC to return to FDISK Options
----------------------------------------------------------------
     If you reply Y, the screen will be updated to show only the 
primary DOS partition and the message

	  Extended DOS partition deleted

	  Press ESC to return to FDISK Options

Press Esc to return once again to the FDISK Options menu.

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
Active Partitions, Changing of
Configuration of DOS Partitions
Displaying of Partition Information
FDISK Command
Hard Disk Partitions

A)active partition
The section of a hard disk containing the operating system to be 
used when the hardware powers up.

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
hard disk
hardware

A)ANSI driver
A device driver, contained in the ANSI.SYS file, that loads 
additional support for advanced console features.
A)application program
A program that performs or replaces a manual function, such as 
balancing a checkbook or managinginventory.
A)archive bit
A bit in a file specification used to indicate whether the file 
in question needs to be backed up.
A)ASCII
American Standard Code for Information Interchange. The coding 
scheme whereby every character the computer can access is 
assigned an integer code between 0 and 255.
A)assembly language
A symbolic form of computer language used to program computers at 
a fundamental level.
A)asynchronous communications
See serial communications.
A)AUTOEXEC.BAT
A batch file executed automatically whenever the computer is 
booted up.
A)background task
A second program running on your computer; usually, a printing 
operation that shares the CPU with your main foreground task.
A)base name
The portion of a file name to the left of the period separator; 
it can be up to eight characters long.
A)BASIC
Beginner's All-purpose Symbolic Instruction Code. A computer 
language similar to the English language.
A)batch file
An ASCII file containing a sequence of DOS commands that, when 
invoked, will assume control of the computer, executing the 
commands as if they were entered successively by a computer user.
A)baud rate
The speed of data transmission, usually in bits per second.

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
bit
binary
byte

A)binary
A numbering system that uses powers of 2 to generate all other 
numbers.

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
baud rate
bit
byte

A)bit
One-eighth of a byte. A bit is a binary digit, either 0 or 1.

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
baud rate
binary

A)bit mapping
The way a graphics screen is represented in the computer. Usually 
signifies point-to-point graphics.
A)booting up
See bootstrapping.
A)boot record
The section on a disk that contains the minimum information DOS 
needs to start the system.
A)bootstrapping
When the computer initially is turned on or is rebooted from the 
keyboard with Ctrl-Alt-Del, it ``pulls itself up by its 
bootstraps.'' See also warm booting, cold booting.
A)branching
The transfer of control or execution to another statement in a 
batch file. See also decision making.
A)Break key
The control-key combination that interrupts an executing program 
or command; activated by pressing the Scroll Lock/Break key while 
holding down the Ctrl key.
A)buffer
An area in memory set aside to speed up the transfer of data, 
allowing blocks of data to be transferred at once.
A)byte
The main unit of memory in a computer. A byte is an 8-bit binary-
digit number. One character usually takes up one byte.

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
binary
bit
baud rate

A)cache
A portion of memory reserved for the contents of recently 
referenced disk sectors. Facilitates faster reaccess of the 
same sectors.
A)case sensitivity
Distinguishing between capital letters and lowercase letters.
A)chaining
Passing the control of execution from one batch file to another. 
This represents an unconditional transfer of control.
A)character set
A complete group of 256 characters can be used by programs or 
system devices. Consists of letters, numbers, control codes, and 
special graphics or international symbols. See also code page.
A)cluster
A group of contiguous sectors on a disk. This is the smallest 
unit of disk storage that DOS can manipulate.
A)COBOL
A programming language usually used for business applications.
A)code page
A character set that redefines the country and keyboard 
information for non-n-U.S. keyboards and systems.
A)cold booting
When the computer's power is first turned on and DOS first boots 
up. See bootstrapping.
A)COMMAND.COM
The command processor that comes with DOS.
A)command line
The line on which a command is entered. This line contains the 
command and all of its associated parameters and switches. It may 
run to more than one screen line, but it is still one command 
line.
A)command processor
The program that translates and acts on commands.
A)compressed print
Printing that allows more than 80 characters on a line of output 
(usually 132 characters, but on newer printers up to255 
characters per line).
A)computer-aided design (CAD) program
A sophisticated software package containing advanced graphics and 
drawing features.Used by engineers, architects, and designers for 
drawing and de-sign applications.
A)concatenation
The placing of two or more text files together in a series.
A)conditional statement
A statement in a batch file that controls the next step to be 
executed in the batch file, based on the value of a logical test.
A)CONFIG.SYS
An ASCII text file containing system configuration commands.
A)configuration
An initial set of system values, such as the number of buffers 
DOS will use, the number of simultaneously open files it will 
allow, and the specific devices that will be supported.
A)console
The combination of your system's monitor and keyboard.
A)contiguity
That the disk sectors used by a file are physically adjacent on a 
disk.
A)control codes
ASCII codes that do not display a character but perform a 
function, such as ringing a bell or deleting a character.
A)copy protection
Special mechanisms contained in diskettes to inhibit the copying 
of them by conventional commands.
A)CPU
Central Processing Unit. The main chip that executes all 
individual computer instructions.
A)Ctrl-Z
The end-of-file marker.
A)cursor
The blinking line or highlighted box that indicates where the 
next keystroke will be displayed or what the next control code 
entered will affect.
A)cutting and pasting
Selecting text from one part of a document or visual display and 
moving it to another location.
A)cylinder
Two tracks that are in the same place on different sides of a 
double-sided disk. May be extended to include multiple platters. 
For example, Side 0 Track 30, Side 1 Track 30, Side 2 Track 30, 
and Side 3 Track 30 form a cylinder.
A)daisy-wheel printer
A printer that uses circular templates for producing letter-
quality characters.
A)data area
The tracks on a disk that contain user data.
A)database
A collection of data organized into various categories. A phone 
book is one form of database.
A)database management system
A software program designed to allow the creation of specially 
organized files, as well as data entry, manipulation, removal, 
and reporting for those files.
A)data bits
The bits that represent data when the computer is communicating.
A)data disk
A disk that has been formatted without the /S switch. The disk 
can contain only data; no room has been reserved for system 
files.
A)data stream
The transmission of data between two components or computers.
A)dead key
A reserved key combination on international keyboards, which 
outputs nothing itself but allows the next keystroketo produce an 
accent mark above or below the keystroke's usualcharacter.
A)debugging
The process of discovering what is wrong with a program, where 
the problem is located, and what the solution is.
A)decimal
A numbering system based on ten digits.
A)decision making
A point in a batch file at which execution can continue on at 
least two different paths, depending on the results of a program 
test. Also known as logical testing or branching.
A)default
The standard value of a variable or system parameter.
A)deferred execution
In a program or batch file, when execution is delayed until a 
value for some parameter is finally entered or computed. 
A)delimiter
A special character, such as a comma or space, used to separate 
values or data entries.
A)destination
The targeted location for data, files, or other information 
generated or moved by a DOS command.
A)device
Any internal or external piece of peripheral hardware.
A)device driver
Also known as an interrupt handler. A special program that must 
be loaded to use a device. Adds extra capability to DOS.
A)device name
Logical name that DOS uses to refer to a device.
A)digital
A representation based on a collection of individual digits, such 
as 0s and 1s in the binary number system.
A)digitizer
A device with a movable arm that can take an image and break it 
up into small parts, which the computer translates into bits.
A)directory
A grouping of files on a disk. These files are displayed together 
and may include access to other directories (subdirectories).

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
directory tree
file
path
subdirectory

A)directory tree
The treelike structure created when a root directory has several 
subdirectories, each of the subdirectories has subdirectories, 
and so on.

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
directory
file
path
subdirectory

A)disk drive
A hardware device that accesses the data stored on a disk.

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
hardware

A)diskette
A flexible, oxide-coated disk used to store data. Also called a 
floppy diskette.

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
disk drive
hardware

A)disk optimizer
A program that rearranges the location of files stored on a disk 
in order to make the data in those files quickly retrievable.
A)DOS
Disk Operating System. A disk manager and the program that allows 
computer/user interaction.
A)DOS environment
A part of memory set aside to hold the defaults needed in the 
current environment, such as COMSPEC, PATH, LASTDRIVE, and so on.
A)DOS prompt
Usually C or A. The visual indication that DOS is waiting for a 
command or prompting you for input.
A)dot-matrix printer
A printer that represents characters by means of tiny dots.
A)double-density diskette
A diskette on which magnetic storage material is arranged twice 
as densely as usual, allowing the storage of twice the usual 
amount of data. Generally refers to a 360K, 5-inch diskette.
A)drive identifier
A single letter assigned to represent a drive, such as drive A or 
drive B. Usually requires a colon after it, such as A:.
A)DRIVER.SYS
A file containing a device driver for an extra external disk 
drive. Used in the CONFIG.SYS file.
A)dual tasking
Causing two tasks or programming events to occur simultaneously.
A)echoing
Displaying on your video monitor the keystrokes you type in.
A)EDLIN
The DOS line editor.
A)end-of-file marker
A Ctrl-Z code that marks the logical end of a file.
A)environment
The context within which DOS interfaces with you and with your 
commands.
A)error level
A code, set by programs as they conclude processing, that tells 
DOS whether an error occurred, and if so, the severity of that 
error.
A)expansion cards
Add-on circuit boards through which hardware can increase the 
power of the system, such as adding extra memory or a modem.
A)expansion slots
Connectors inside the computer in which expansion cards are 
placed so that they tie in directly to the system.
A)extended ASCII codes
ASCII codes between 128 and 255, which usually differ from 
computer to computer.
A)extended DOS partition
A hard-disk partition used to exceed the 32 megabyte, single-disk 
barrier; it can be divided into logical disk drives.
A)extended memory
Additional physical memory beyond the DOS 1 megabyte addressing 
limit.
A)extension
The one to three characters after the period following the base 
name in a file specification.
A)external buffer
A device, connected to the computer and another device, that acts 
as a buffer.
A)file
A collection of bytes, representing a program or data, organized 
into records and stored as a named group on a disk.

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
directory
directory tree
path
subdirectory

A)file allocation table (FAT)
A table of sectors stored on a disk, which tells DOS whether a 
given sector is good, bad, continued, or the end of a chain of 
records.
A)file name
The name of a file on the disk. Usually refers to the base name, 
but can include the extension as well.
A)file version
A term that refers to which developmental copy of a software 
program is being used or referenced.
A)filter
A program that accepts data as input, processes it in some 
manner, and then outputs the data in a different form.
A)fixed disk
IBM's name for a hard disk.
A)floppy diskette
See diskette.
A)flow of control
The order of execution of batch file commands; how the control 
flows from one command to another, even when the next command to 
be executed is not located sequentially in the file.
A)foreground task
The main program running on your computer, as opposed to the less 
visible background task (usually a print-ing job).
A)formatting
The placement of timing marks on a disk to arrange the tracks and 
sectors for subsequent reading and writing.
A)fragmentation
A condition in which many different files have been stored in 
noncontiguous sectors on a disk.
A)function keys
Special-purpose keys on a keyboard, which can be assigned unique 
tasks by DOS or by application programs.
A)global characters
See wildcards.
A)graphics mode
The mode in which all screen pixels on a monitor are addressable 
and can be used to generate detailed images. Contrasts with text 
mode, which usually allows only 24 lines of 80 characters.
A)hard disk
A rigid platter that stores data faster and at a higher density 
than a floppy diskette. Sealed in an airtight compartment to 
avoid contaminants that could damage or destroy the disk.

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
active partition
head
hardware

A)hardware
The physical components of a computer system.

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
active partition
diskette
hard disk
disk drive

A)hardware interrupt
A signal from a device to the computer, indicating that an event 
has taken place.
A)head
A disk-drive mechanism that reads data from and writes data to 
the disk.

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
hard disk
head crash

A)head crash
Occurs when the head hits the disk platter on a hard disk, 
physically damaging the disk and the data on it.

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
head

A)help file
A file of textual information containing helpful explanations of 
commands, modes, and other on-screen tutorial information.
A)hexadecimal
A numbering system in base 16. A single 8-bit byte can be fully 
represented as two hexadecimal digits.
A)hidden files
Files whose names do not appear in a directory listing. Usually 
refers to DOS' internal system files, but can also refer to 
certain files used in copy-protection schemes.
A)high-capacity diskette
A 1.2 megabyte, 5--inch floppy diskette.
A)high-resolution mode
The mode on a video monitor in which all available pixels are 
used to provide the most detailed screen image possible. On a 
color monitor, this mode reduces the possible range of colors 
that can be output.
A)horizontal landscape
When output to a printer is not done in the usual format, but 
rather with the wider part of the paper laid out horizontally, as 
in a landscape picture.
A)hot key
A key combination used to signal that a memory-resident program 
should begin operation.
A)housekeeping
Making sure the directory stays intact and well organized, and 
that unnecessary files are deleted.
A)hub
The center hole of a diskette.
A)IF
A conditional statement in a batch file.
A)ink-jet printer
A printer that forms characters by spraying ink in a dot pattern. 
See dot-matrix printer.
A)interface
The boundary between two things, such as the computer and a 
peripheral.
A)interrupt
A signal sent to the computer from a hardware device, indicating 
a request for service or support from the system.
A)keyboard translation table
An internal table, contained in the keyboard driver, that 
converts hardware signals from the keyboard into the correct 
ASCII codes.
A)key combination
When two or more keys are pressed simultaneously, as in Ctrl-
Scroll Lock or Ctrl-Alt-Del.
A)key redefinition
Assigning a nonstandard value to a key.
A)kilobyte (K)
1024 bytes.
A)laser printer
A printer that produces images (pictures or text) by shining a 
laser on a photostatic drum, which picks up toner and then 
transfers the image to paper.
A)LCD
Liquid Crystal Display. A method of producing an image using 
electrically sensitive crystals suspended in a liquid medium.
A)letter-quality printer
A printer that forms characters that are comparable to those of a 
typewriter.
A)line editor
A program that can make textual changes to an ASCII file, but can 
only make changes to one line of the file at a time.
A)line feed
When the cursor on a screen moves to the next line, or when the 
print head on a printer moves down the paper to the next line.
A)literal
Something that is accepted exactly as it was submitted.
A)lockup
Occurs when the computer will not accept any input and may have 
stopped processing. Requires that the computer be warm or cold 
booted to resume operating.
A)log file
A separate file, created with the BACKUP command, that keeps 
track of the names of all files written to the backup 
diskette(s).
A)logging on
Signing onto a remote system, such as a mainframe or 
telecommunications service.
A)logical
Something that is defined based on a decision, not by physical 
properties.
A)logical drives
Disk drives, created in an extended DOS partition, that do not 
physically exist, but DOS operates as if they do. A means for DOS 
to access a physical disk that has more than 32 megabytes 
available.
A)logical testing
See decision making.
A)machine language
The most fundamental way to program a computer, using 
instructions made up entirely of strings of 0sand 1s.
A)macro
A set of commands, often memory-resident. When executed, they 
appear to the program executing them as if they were being 
entered by you.
A)medium-resolution mode
The mode on a Color Graphics Adapter in which only 320x200 pixels 
of resolution are allowed.
A)megabyte (Mb)
1024 kilobytes.
A)memory
The circuitry in a computer that stores information. See also RAM
and ROM.
A)memory-resident
Located in physical memory, as opposed to being stored in a disk 
file.
A)menu
A set of choices displayed in tabular format.
A)meta symbols
Special single-character codes used by the PROMPT command to 
represent complex actions or sequences to be included in the DOS 
prompt.
A)microfloppy diskette
The 3-inch diskette format used in the new PS/2 and many other 
computers.
A)modem
A device that transmits digital data in tones over a phone line.
A)monitor
The device used to display images; a display screen.
A)monochrome
Using two colors only: the background and foreground.
A)mouse
A device that moves the screen cursor by means of a hand-held 
apparatus moved along a surface such as a desk. The computer can 
tell how far and in which direction the mouse is being moved.
A)multitasking
When two or more computing applications are executing 
simultaneously.
A)national language-support operations
The DOS 3.3 feature that supports displays and printers, using a 
new range of code and character groupings.
A)network
Several computers, connected together, that can share common data 
files and peripheral devices.
A)nibble
Four bits, or half a byte.
A)octal
A numbering system in base 8.
A)operating system
See DOS.
A)overlay files
Files containing additional command and control information for 
sophisticated and complex programs. An overlay file is usually 
too large to fit into memory along with the main .EXE or .COM
file.
A)overwriting
Typing new data over what is already there.
A)parallel communications
Data transmission in which several bits can be transferred or 
processed at one time.
A)parameter
An extra bit of information, specified with a command, that 
determines how the command executes.
A)parity bit
The bit, added to the end of a stream of data bits, that makes 
the total of the data bits and the parity bits odd or even.
A)partition
The section of a hard disk that contains an operating system. 
There can be at most four partitions on one hard disk.
A)Pascal
A programming language used mainly in computer science.
A)password
A sequence of characters that allows entry into a restricted 
system or program.
A)path
The list of disks and directories that DOS will search through to 
find a command file ending in .COM, .BAT, or .EXE.

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		  [For related topics, press R]

    SEE ALSO
directory
directory tree
file
subdirectory

A)peripheral
Any physical device connected to the computer.
A)piping
Redirecting the input or output of one program or command to 
another program or command.
A)pixel
The smallest unit of display on a video monitor- -in short, a 
dot- -that can be illuminated to create text or graphics images.
A)platter
The rigid disk used in a hard disk drive.
A)plotter
A device that draws data on paper with a mechanical arm.
A)port
A doorway through which the computer can access external devices.
A)primary DOS partition
Up to the first 32 megabytes of a hard disk. Contains the boot 
record and other DOS information files.
A)printer
A device that outputs data onto paper using pins (dot matrix), a 
daisy wheel, ink jets, laser imaging, and so on.
A)public domain
Something not copyrighted or patented. Public domain software can 
be used and copied without infringing on anyone's rights.
A)queue
A series of files waiting in line to be printed.
A)RAM
Random Access Memory. The part of the computer's memory to which 
you have access; stores programs and data while the computer is 
on.
A)RAM disk
An area of RAM that acts as if it were a disk drive. All data in 
this area of memory is lost when the computer is turned off or 
warm booted. Also known as a virtual disk.
A)range
A contiguous series of values (minimum to maximum, first to last, 
and so on).
A)read-after-write verification
An extra level of validity checking, invoked with the VERIFY 
command or the /V switch. Rereads data after writing it to disk, 
comparing the written data to the original information.
A)read-only status
Indicates that a file cannot be updated but can be read.
A)read/write bit
The bit in a file specification that indicates whether a file can 
accept changes or deletions, or can only be accessed for reading.
A)redirection
Causing output from one program or device to be routed to another 
program or device.
A)REM statement
A line in a BASIC program containing remarks or comments for 
program explanation or clarification.
A)reserved names
Specific words, in a programming language or operating system, 
that should not be used in any other application context.
A)resident commands
Commands located in random access memory.
A)resource allocation
Making system facilities available to individual users or 
programs.
A)reverse video
Black letters on a white background.
A)ROM
Read-Only Memory. The section of memory that you can only read 
from. This contains the basic computer operating system and 
system routines.
A)root directory
The first directory on any disk.
A)scan code
The hardware code representing a key pressed on a keyboard. 
Converted by a keyboard driver into an ASCII code for use by DOS 
and application programs.
A)scrolling
What the screen does when you're at the bottom of it and press 
Return- -all of the lines roll up.
A)secondary command processor
A second copy of COMMAND.COM, invoked either to run a batch file 
or to provide a new context for subsequent DOS commands.
A)sector
A division of a disk track; usually, 512 bytes.
A)serial communications
Data transmission in which data is transferred and processed one 
bit at a time. Also known as asynchronous communications.
A)shareware
Public domain software. See also public domain.
A)snapshot program
A program used in debugging to store the status of system or 
application program variables.
A)software
The programs and instruction sets that operate the computer.
A)software interrupt
A signal from a software program that calls up a routine that is 
resident in the computer's basic programming. Also, a software 
signal to the computer that the software program has finished, 
has a problem, and so on.
A)source
The location containing the original data, files, or other 
information to be used in a DOS command.
A)spooling
Simultaneous Peripheral Operations On-Line. Using a high-speed 
disk to store input to or output from low-speed peripheral 
devices while the CPU does other tasks.
A)spreadsheet program
An electronic version of an accountant's spreadsheet; when one 
value changes, all other values based on that value are updated 
instantly.
A)start bit
The bit sent at the beginning of a data stream to indicate that 
data bits follow.
A)stop bit
The bit sent after the data bits, indicating that no more data 
bits follow.
A)string
A series of characters.
A)subcommands
Several special commands used only within batch files.
A)subdirectory
A directory contained within another directory or subdirectory. 
Technically, all directories other than the root directory are 
subdirectories.

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
directory
directory tree
file
path

A)switch
A parameter included in DOS commands, usually preceded by the 
slash (/) symbol, that clarifies or modifies the action of the 
command.
A)synchronization
The coordination of a sending and receiving device, so that both 
simultaneously send and receive data at the same rate.
A)system disk
A disk containing the necessary DOS files for system booting.
A)text mode
The mode in which standard characters can be displayed on a 
monitor.
A)time slice
The smallest unit of time managed and assigned by the operating 
system to programs and other processing activities.
A)toggle
A switch or command that reverses a value from off to on, or from 
on to off.
A)track
A circular stream of data on the disk. Similar to a track on a 
record, only not spiraling.
A)transient command
A command whose procedures are read from the disk into memory, 
executed from memory, and then erased from memory when finished.
A)utility
A supplemental routine or program designed to carry out a 
specific operation, usually to modify the system environment or 
perform housekeeping tasks.
A)variable parameter
A named element, following a command, that acts as a placeholder; 
when you issue the command, you replace the variable parameter 
with the actual value you want to use.
A)verbose listing
A listing of all files and subdirectories contained on the disk 
and path specified in the command. Activated by the CHKDSK 
command with the /V switch.
A)vertical portrait
The conventional 8-by-11-inch output for printed information, 
with the long side of the paper positioned vertically.
A)virtual disk
See RAM disk.
A)volume label
A name, consisting of up to 11 characters, that can be assigned 
to any disk during a FORMAT operation or after formatting with 
the LABEL command.
A)warm booting
Resetting the computer using the Ctrl-Alt-Del key combination. 
See bootstrapping.
A)wide directory listing
An alternate output format that lists four columns of file names.
A)wildcards
Characters used to represent any other characters. In DOS, * and 
? are the only wildcard symbols.
A)word processor
A computerized typewriter. Allows the correction and reformatting 
of documents before they are printed.
A)write-protection
Giving a disk read-only status by covering the write-protect 
notch.

A)Character Sets

     Just as you use an alphabet and a decimal numbering system, 
the computer uses its own character and numbering system. DOS 
maintains, in memory, all of the characters of the English 
alphabet, including numbers and symbols, as well as some foreign 
symbols (such as accented vowels). This group of symbols is 
called a character set. By changing the symbols in this set, you 
can obtain completely new character sets. This is especially 
useful for people living in other countries, who have less daily 
need of U.S. standard characters and who would rather work with 
their own characters.
    ASCII Codes

     A character is any letter, number, punctuation symbol, or 
graphics symbol. In other words, it is anything that can be 
displayed on a video screen or printed on a printer.
     Each character in a character set has a number assigned to 
it, which is how the computer refers to the various characters in 
the set. For example, code 65 refers to a capital A, and code 97 
refers to a lowercase a. These codes are called ASCII codes 
(pronounced ``ask-ee codes''); ASCII stands for American Standard
Code for Information Interchange.
     Codes 0 through 31 are used as control codes. Displaying one 
of these codes will cause something to happen instead of causing 
a symbol to be displayed. For example, displaying code 7 will 
result in the computer's bell or beeper being sounded. Displaying 
code 13 will result in a carriage return.
     Codes 32 through 127 are ASCII character codes for numbers, 
letters, and all punctuation marks and symbols. Codes 128 through 
255, known as extended ASCII codes, vary from computer to 
computer. They usually comprise foreign characters, Greek and 
mathematical symbols, and graphics characters. (Graphics 
characters consist of small lines and curves that can be used to 
create geometric patterns.)
     DOS 3.3 has several available ASCII tables, called code 
pages. The most common is the standard U.S. code page; the next 
most common is the Multilingual code page.
    Mapping Character Sets

     Any device that displays characters has a device driver that 
literally drives, or controls, the device. When the computer 
tells a printer to print the letter A, DOS sends the code 65 to 
the printer driver, which converts the 65 into a series of 
control codes that will print the A.
     For the sake of consistency, computers, printers, and 
displays all have the same character sets and coding system for 
ASCII codes 32 through 127. This ensures that when you press a 
key, the desired character will be displayed, and the same 
character will be printed by your printer.
     The process of matching ASCII codes against characters in a 
character set is called mapping.

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
Numbering Systems

A)Numbering Systems

     Computers use a variety of numbering systems to operate. The 
most basic numbering system is the binary system, in which there 
are only two digits, 0 and 1. The digital circuitry used in 
computers operates by using small voltages that turn magnetic 
bits on or off. Therefore, 0 and 1 are used to represent the two 
states of off and on, respectively.
     Counting in binary is not difficult, but it does require 
some adjustment from the standard decimal-numbering scheme. The 
progression of numbers and their matching decimal conversions are 
shown in the table below.
----------------------------------------------------------------
     Binary	    Decimal
          0              0
          1              1
         10              2
         11              3
        100              4
        101              5
        110              6
        111              7
       1000              8
       1001              9
       1010             10
----------------------------------------------------------------
     The general rule for converting numbers from binary to 
decimal is to multiply the number in every binary number column 
by 2 raised to the column-number power. You count column numbers 
from the right, starting with 0. For the binary number 1101, for 
example, you would obtain

     (1x20)+(0x21)+(1x22)+(1x23)

where any number to the 0 power (20 in this case) is defined as 
equal to 1. This is called counting in base 2.
     The decimal system counts in base 10. Using the same method
of converting binary numbers, you can see that breaking down the 
decimal number 2014 into its component parts works like this:

     (4x100)+(1x101)+(0x102)+(2x103)
      =4+10+000+2000
      =2014

Another numbering system is called octal, or base 8. This system
has only eight digits, 0 to 7. The octal number 701 is converted 
to base 10 (decimal) by the following computation:

     (1x80)+(0x81)+(7x82)
      =1+0+448
      =449

The last major numbering system in computers is called 
hexadecimal, which counts in base 16. This system has 16 digits
in it: 0 to 9 and A to F, which form the counting sequence 
0123456789ABCDEF. To count in this system, you use the same 
method you use for other numbering systems. The hexadecimal 
number BA7 translates to decimal as

     (7x160)+x161)+(Bx162)

which is equal to

     7+(10x161)+(11x162)

which is also equal to

     7+160+2816
     =2983

The table below demonstrates how to count in hexadecimal.
----------------------------------------------------------------
     Hexadecimal	 Decimal
          0                   0
          .                   .
          .                   .
          9                   9
          A                  10
          B                  11
          .                   .
          .                   .
          F                  15
         10                  16
          .                   .
          .                   .
         1A                  26
----------------------------------------------------------------
     Hexadecimal notation is convenient for byte values because a 
hexadecimal digit is equivalent to 4 (24=16) binary digits 
(called a nibble) and there are 8 bits (28=256-character set) in
a byte. A byte can therefore be represented by two hexadecimal 
digits.


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		  [For related topics, press R]

    SEE ALSO
Character Sets


A)AUTOEXEC.BAT File

     You can create a special batch file, named AUTOEXEC.BAT, 
which contains all of the DOS commands that you wish to have 
invoked every time you start your computer. The command 
statements in the AUTOEXEC.BAT file often include such DOS 
commands as DATE, TIME, PROMPT, PATH, and SET. These can also 
include commands that execute special RAM-resident programs such 
as Lightning or SideKick or a menu program of your own design. 
Such a program would allow you to start up specific application 
programs available on your PC- -dBASE III PLUS, Lotus 1-2-3, or 
WordPerfect, for example.
     Every time you start your computer, DOS checks for the 
presence of the AUTOEXEC.BAT file on either the disk in drive A 
if you are using a two-floppy disk system, or in the root 
directory of drive C if you are using a hard disk system. If DOS 
locates such a file, it automatically executes the statements it 
contains upon completion of the boot sequence.
     When you create the AUTOEXEC.BAT file, remember to include 
the DATE and TIME commands along with the other commands you wish 
executed each time you start the computer. (If your computer is 
equipped with a clock/calendar card, enter the appropriate 
commands to have the date and time read.) If you do not add 
these commands, DOS will no longer prompt you for the current 
date and time as part of the start-up procedure and, as a result, 
the files you create with your application programs will not be 
stamped with the correct date and time.
     Consider the following example created with the COPY command 
and containing a sampling of DOS commands typically used in the 
AUTOEXEC.BAT file:

	  COPY CON AUTOEXEC.BAT
	  DATE
	  TIME
	  PROMPT $p$g
	  PATH = C:\;C:\DOS;C:\BATCH
	  Ctrl-Z

     After creating this AUTOEXEC.BAT file, when you start your 
computer DOS will first prompt you to update the date and time. 
Once you have responded to these commands, DOS changes the prompt 
so that it always displays the current directory, and then sets 
the path so that it will check the root, \DOS, and \BAT 
directories for any command that you enter, regardless of which 
directory you are in at the time.

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO

     Batch Files
     Creation of Batch Files
     Displaying of Text with Batch Files
     ECHO batch file command
     Replaceable Parameters in Batch Files
     Loops in Batch Files
     Conditional Processing
     Chaining of Batch Files
     Subroutines for Batch Files
     PATH Command
     PRINT Command
     SET Command

A)Displaying of Text with Batch Files

     The batch files that you create can contain messages that 
are displayed to alert the user to the underlying purpose of the 
batch file or to prompt the user to take a particular step- -such 
as changing data disks- -during a pause in the execution of a 
command. You can also add messages that are displayed as part of 
the ECHO command, which controls whether the command statements 
entered in the batch file are displayed to the user as they are 
executed by DOS.
    REM Command

     One way to have text displayed on the screen during the 
execution of a batch command is with the use of the REM (remark) 
command 

	  REM remark

where

	  remark	 Specifies the comment to be added to a
                         batch file.

     DOS will not try to execute a REM command, although it will 
display REM and the text that follows it on the screen unless it 
has previously executed an ECHO OFF statement (see Using the ECHO 
Command, which follows).
     You can use the REM command to add messages to the batch 
file that help make clear its function and procedure. If you wish 
to add a nonprinting comment whose purpose is to document the use 
of particular commands in your batch file but that is never to be 
displayed on the screen to the user, you simply preface the text 
of this type of comment with a colon, as in:

	  :Start backup

Comments prefaced with a colon will appear when you use the TYPE 
command to display the contents of the batch file on your screen, 
or when you use the COPY or PRINT command to obtain a printout.
    PAUSE

     You can also have messages displayed on the screen during a 
pause in the execution of batch file commands. The syntax for the 
PAUSE command is 

	  PAUSE [message]

where

	  [message]	 Specifies the message you want to have
                         displayed on the screen when PAUSE is 
                         invoked.

     When DOS encounters a PAUSE statement, it pauses the 
execution of the commands in the batch file and displays your 
message on the screen, followed by its own message

	  Strike a key when ready. . .

on the line below. If you enter the PAUSE command without any 
message text, you will see only this DOS message instructing you 
to strike a key to continue the execution of the batch file.
     When you use the PAUSE command, the word PAUSE is always
displayed on the screen along with the message you have entered 
(just as when using the REM command). If the batch file has 
executed an ECHO OFF command before it encounters your PAUSE 
command, neither the word PAUSE nor the text of your message will
be displayed on the screen. Only the DOS message about striking a 
key to continue will be visible (see Using the ECHO batch file command, 
which follows).

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO

     Batch Files
     Creation of Batch Files
     AUTOEXEC.BAT File
     Displaying of Text with Batch Files
     ECHO batch file command
     Replaceable Parameters in Batch Files
     Loops in Batch Files
     Conditional Processing
     Chaining of Batch Files
     Subroutines for Batch Files
     PRINT Command
     TYPE Command

A)ECHO

     When DOS executes the commands in a batch file, it can 
display each command statement on the screen as it is executed. 
You can enter the ECHO command in the batch file to control 
whether the command statements are displayed. The syntax is 

	  ECHO	[OFF]

or

	  ECHO	[ON]

where

          OFF            Suppresses the display of command 
                         statements during the execution.
          ON             Used if you wish to have subsequent 
                         commands displayed on the screen during 
                         the execution of the batch file.

     Note that if you enter the ECHO command in a batch file (or 
at the DOS prompt) without using either the ON or OFF parameters, 
DOS responds by displaying the current state of the ECHO command. 
You will see either ECHO is on or ECHO is off.
     If you are using DOS 3.3, you can also suppress the display 
of a command statement in the batch file by prefacing it with the 
@ symbol. For example, entering

	  @VERIFY ON

will prevent the VERIFY ON command from being displayed. However, 
each command statement that you wish to suppress must be prefaced 
by an @ symbol. If you use @ECHO OFF, the ECHO OFF command as 
well as all subsequent statements are automatically suppressed 
until an ECHO ON command occurs.
     When ECHO is off, only the display of the command statements 
in the batch file will be suppressed. DOS will continue to 
display any message that is normally shown after a particular 
commandhas been processed. For instance, if your batch file 
contains the statement

	  ECHO	OFF

followed by a command to copy a particular file from one 
directory to another, you will still see the DOS message

	  1 File(s) copied

although you will not see the contents of the COPY command itself 
on the line above it. Note that you can often get rid of these 
messages by redirecting output to NUL:

	  COPY *.* A: NUL

     You can use the ECHO command to display messages to the 
user. First, set ECHO to off. Then, enter an ECHO command 
followed by at least one space and the text of your message. When 
you use the ECHO command in this way, only your message is 
displayed onthe screen. DOS does not include the command word 
(ECHO) as it does when displaying messages with the REM or PAUSE 
commands.
     For example, you could have your batch file display a prompt 
to insert a data disk in drive A by using the ECHO and PAUSE 
commands as follows:

	  ECHO	OFF
	  .
	  .
	  .
	  ECHO	Insert data disk in drive A
	  PAUSE

When the batch file executes these last two commands, you see 
only

	  Insert data disk in drive A
	  Strike a key when ready. . .

on the screen. ECHO does not appear along with the prompt 
message, but the separate PAUSE command causes the Strike a key
when ready. . . message to be displayed.
     When you use the ECHO command to display messages and 
prompts, be sure that it is preceded by an ECHO OFF statement (or 
an @ symbol if you are using DOS 3.3) in the batch file. 
Otherwise, you will see the ECHO command statement containing the 
message as well as the message itself when the batch file is run.
     Note that the use of the REM, PAUSE, and ECHO commands to 
display on-screen messages slows down the execution of the batch 
file appreciably. If you need to include extensive instructions 
for a particular batch file, use the TYPE command to have them 
displayed on the screen.

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO

     Batch Files
     Creation of Batch Files
     AUTOEXEC.BAT File
     Displaying of Text with Batch Files
     Replaceable Parameters in Batch Files
     Loops in Batch Files
     Conditional Processing
     Chaining of Batch Files
     Subroutines for Batch Files
     COPY Command

A)Replaceable Parameters in Batch Files

     You can define parameters (or arguments) that are passed to 
particular command statements in a batch file with the use of 
replaceable or dummy parameters. This makes the batch file more 
flexible because you get to define the arguments to be passed to 
the command statements at the time you execute the batch file.
     You can define up to ten different replaceable parameters to 
be used in a batch file. Each one is given a number between 0 and 
9 preceded by the percent sign, as in %1, %2, and so on. Note, 
however, that the replaceable parameter %0 represents a special 
case: it is always replaced with the file name of the batch file.
     The other nine replaceable parameters have no such fixed 
replacements: you can make then stand for DOS commands, file 
names, parts of file names (such as extensions), directory paths, 
and the like. For instance, you could use replaceable parameters 
to create a batch file named WHEREIS.BAT that locates a 
particular file for you. This batch file contains only a single 
command statement using the replaceable argument, as follows:

	  CHKDSK /V | FIND ``%1''

The CHKDSK command with the /V parameter lists all of the files 
and subdirectories for the current directory and pipes this 
information to the FIND command.
     The FIND command contains the replaceable parameter %1. When 
you execute the WHEREIS.BAT file, you enter the filename you wish 
to locate along with the batch file name. To locatea file called 
LOAN.FRM on the hard disk, you run the batch fileby entering

	  WHEREIS LOAN.FRM

DOS will then execute WHEREIS.BAT as though you had entered

	  CHKDSK /V|FIND ``LOAN.FRM''

as the command statement. If this file is located in C:\WP\FORMS, 
DOS will respond by displaying

	  C:\WP\FORMS\LOAN.FRM

As you can see, you can use this same batch file to search for 
any file or group of files, simply by entering a different file 
name at the time you execute it.
     In complex batch files, you may find that ten replaceable 
parameters are not sufficient. In such a case, you can use the 
SHIFT command. SHIFT discards each argument after it has been 
acted upon, replacing it with the next argument so that after the 
first argument is processed, the second becomes the first, the 
third the second, and so on. After you use the SHIFT command, the 
0% argument is never acted upon, since the %n argument becomes
the %(n--1) argument. Note that SHIFT is useful in loops, which
are described later in this appendix.
    Passing Arguments from the Environment
     
     As noted in the SET reference entry, you can specify a set 
of strings that the batch files can refer to. For example, if you 
enter the SET command

	  SET REPORT = YREND

and have previously entered the following command line in a batch 
file

	  COPY %REPORT%.WK1 A:

the batch file will copy the file named YREND.WK1 to the floppy 
disk in drive A when the batch file is run.
     Note that the replaceable argument in the batch file command 
line is enclosed in a pair of percent signs (%). This indicates 
to DOS that the argument is to be taken from the environment.

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
     Batch Files
     Creation of Batch Files
     AUTOEXEC.BAT File
     Displaying of Text with Batch Files
     ECHO batch file command
     Replaceable Parameters in Batch Files
     Loops in Batch Files
     Conditional Processing
     Chaining of Batch Files
     Subroutines for Batch Files
     COPY Command
     FIND Command

A)Loops in Batch Files

     There are several methods for creating loops in batch files. 
If you want the entire batch file to repeat, you can use the %0 
replaceable parameter as the last command. You will recall that 
%0 is always replaced with the file name of the batch file. When 
you add it asthe last statement in a batch file, it causes all of 
the commands in thefile to be repeated. For example, if you 
create a batch file namedDIRA.BAT that contains the command 
statements

	  ECHO OFF
	  ECHO Insert new disk in drive A
	  PAUSE
	  DIR A:/p
	  %0

the file will repeatedly prompt you to insert a different disk in 
drive A and then give you a directory listing of all of the files 
it contains when you press a key to continue. This batch file 
will continue to repeat until you press Ctrl-C or Ctrl-Break to 
terminate it.
    The FOR Loop

     To repeat a command within a batch file for a specific 
number of cases, you use the FOR command. The syntax for the FOR 
command is 

	  FOR %%variable IN (set) DO command

where

	  command	 Specifies the command to be executed for
			 each member listed in the (set)
                         argument, in the order in which these 
			 members are entered. The command
                         argument can consist of only a single 
                         command, which can be another batch file 
                         command (except for the FOR command), an 
                         executable program, batch file, or DOS 
                         command. Note that you cannot nest FOR 
			 batch commands, which is why the command
                         argument cannot contain another FOR 
                         command statement.
	  set		 Specifies files to be operated upon.
	  variable	 Specifies the variable to be operated on
			 by the command. Notice that a double
                         percent sign is entered before the 
                         variable (usually, though not 
                         necessarily, a single letter) to 
                         distinguish it from a replaceable 
                         parameter.

Consider this example using the FOR command:

	  FOR %%A IN (1985.WK1 1986.WK1 1987.WK1)
	  DO COPY %%A %2

In this batch file, the FOR command statement copies each of the 
three worksheet files listed in the (set) argument to the
directory path entered when the batch file is run by passing it 
to the %2 replaceable parameter. Notice that the command argument
in this example is actually COPY %%A, instead of just COPY.
    The GOTO Command

     You can also cause a batch file to execute (and sometimes 
repeat) a group of command statements in the file beginning at a 
specific point. To do this, you use the GOTO batch command. You 
indicate where in the batch file the commands are to be executed 
(or repeated) by using a label. 
     The syntax of the GOTO command is 

	  GOTO [:]label

where

	  label 	 Specifies a character string of up to
                         eight alphanumeric characters, and is 
                         not case-sensitive. By convention, 
                         alphabetic characters are entered in 
                         lowercase and the label name is prefaced 
                         by a colon. Note that the colon is 
                         mandatory before the actual label, but 
                         optional before the argument in the 
                         GOTO. The label, however, cannot contain 
                         a period (.).

     When you use the GOTO command, DOS executes all of the 
command statements listed below the label until it reaches the 
end of the batch file or another GOTO statement telling it to 
begin reprocessing the commands or to process a new set of 
commands beneath another label.
     Looping with the GOTO command can be illustrated by the 
following generalized form:

	  :label
	  command%1
	  .
	  .
	  .
	  command%n
	  SHIFT
	  GOTO :label

Assuming that the commands listed below the :label contain 
replaceable parameters, with the use of the SHIFT batch command, 
this loop would be executed indefinitely (until you terminated 
the batch file by pressing Ctrl-C or Ctrl-Break).

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
     Batch Files
     Creation of Batch Files
     AUTOEXEC.BAT File
     Displaying of Text with Batch Files
     ECHO batch file command
     Replaceable Parameters in Batch Files
     Loops in Batch Files
     Conditional Processing
     Chaining of Batch Files
     Subroutines for Batch Files

A)Conditional Processing

     The endless loop illustrated above is of limited use in 
batch files. It is much more common to use the GOTO command with 
conditional statements. That way, the commmands listed beneath 
the label are executed only when the condition is true. Using the 
GOTO command with conditions allows you to create batch files 
that branch according to the result of the condition.
     In addition to using conditional processing to branch, you 
can also have command statements executed only when there is 
equivalency between two items or if a particular file exists.
    The IF Command

     The batch IF command is used to allow conditional execution 
of command statements. The syntax of the IF command is as 
follows:

	  IF [NOT] condition command

If you wish to have branching occur as a result of the outcome of 
the condition, use this form:

	  IF [NOT] condition GOTO [:]label

     There is no ELSE command in the batch file command 
vocabulary. If you wish to have the program branch to one set of 
commands if the condition is true and another if it is false, use 
this form:

	  IF condition GOTO [:]labela
	  GOTO [:]labelb

If the condition is true, execution jumps to the commands beneath 
label a. If it is false, it jumps to those beneath label b. Note 
that you do not have to use the second GOTO statement if the 
commands to be executed when the condition is false follow the IF 
statement directly.

    Testing for Equivalence

     The condition argument in an IF command can test for
equivalence between two items. If they are found to be equivalent 
(that is, identical in terms of characters and case), then the 
command statement listed in the command argument is executed.
When you test for equivalence, you use a double equal sign. The 
syntax is as follows:

	  IF string1==string2 command

Note that strings are case-sensitive.
     For example, you could enter the following IF command:

	  IF %1==December GOTO :endofyr

If you execute this batch file and enter December as the first 
replaceable parameter, the batch file will jump to the label 
:endofyr and execute the commands that are listed beneath it.

    Testing for the Existence of a File

     You test for the existence of a particular file as the 
condition argument of the IF command. The syntax for this use is
as follows:

	  IF EXIST [d:][path]filename command

The options are as follows:

	  command	      Specifies a command to be executed
                              only when the file entered for the 
			      d:path filename argument is found
                              on the drive/directory indicated 
                              (if these parameters are omitted, 
                              then in the current directory). 
	  d:pathfilename      Specifies the file to be operated
                              on.

     For example, you might have this IF command statement in a 
batch file:

	  IF EXIST 4QTRTOTL GOTO :yrend

The commands beneath the :yrend label are executed only if DOS 
locates the file named 4QTRTOTL in the current directory. If this 
file is not found, this GOTO statement is ignored.

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
     Batch Files
     Creation of Batch Files
     AUTOEXEC.BAT File
     Displaying of Text with Batch Files
     ECHO batch file command
     Replaceable Parameters in Batch Files
     Loops in Batch Files
     Conditional Processing
     Chaining of Batch Files
     Subroutines for Batch Files

A)Chaining of Batch Files

     You can chain batch files by adding the name of the second 
batch file to be executed as the last statement in the command 
statements of the first batch file. Do not confuse chaining batch 
files with calling a new batch file as a subroutine. When 
chaining batch files, control does not return to the first batch 
file as when using subroutines (see the section on Using 
Subroutines, which follows). Because of this, reference to the 
second batch file must be entered as the last command statement 
in the first batch file. If it is not, the commands below this 
reference in the first file will never be executed.

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
     Batch Files
     Creation of Batch Files
     AUTOEXEC.BAT File
     Displaying of Text with Batch Files
     ECHO batch file command
     Replaceable Parameters in Batch Files
     Loops in Batch Files
     Conditional Processing
     Subroutines for Batch Files

A)Subroutines for Batch Files

     To execute a second batch file as a subroutine (that is, 
have control returned to the first batch file upon execution of 
all command statements in the second file), you must load a 
second copy of the command processor, using the COMMAND command. 
The syntax is

	  COMMAND /C batch

where

          /C             Tells DOS that this a secondary copy of 
                         the command processor. 
	  batch 	 Specifies the batch file you wish to
                         call as a subroutine.

     To have control return to the first batch file and to have 
the secondary copy of the command processor unloaded, the EXIT 
command must be the last statement in the batch file used as a 
subroutine. If you do not place EXIT as the last command 
statement in the called batch file, control will not return to 
the calling batch file and the secondary copy of the command 
processor will continue to run.
    Using The CALL Command

     DOS 3.3 has added a CALL command that allows you to call a 
second batch file as a subroutine (that is, execute the commands 
in a second batch file without terminating the first batch file). 
This command can be used in place of the COMMAND and EXIT 
commands. 
     The syntax of the CALL command is

	  CALL [d:][path]filename

where

	  d:pathfilename	   Specifies the name of the
                                   batch file to be called. When 
                                   entering this file name, do 
                                   not include the .BAT file 
                                   extension.

     You can use the CALL command to call its own batch file. 
However, you need to provide a method whereby the batch file is 
eventually terminated.

------------------------------------------------------------------

		  [For related topics, press R]

    SEE ALSO
     Batch Files
     Creation of Batch Files
     AUTOEXEC.BAT File
     Displaying of Text with Batch Files
     ECHO batch file command
     Replaceable Parameters in Batch Files
     Loops in Batch Files
     Conditional Processing
     Chaining of Batch Files
     COMMAND Command




See also:


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