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- #Default Drive: The disk drive that will be used by default. In most DOS
- commands, if you omit the drive letter, DOS assumes the default drive is to be
- used. The DOS prompt "d>", where "d" is a letter indicates which drive is the
- default.
-
- For example, A> means drive A is the default.
-
- You may change the default drive by entering the drive letter followed by a
- colon.
-
- For example, to change the default drive from A to B, enter:
-
- B: [Return]
-
- The DOS prompt will now show B>
- #Device Names: Standard names used by DOS to identify hardware devices.
-
- CON - console (keyboard/screen)
- COM1 (or AUX) - first asynchronous communications port
- COM2 - second asynchronous communications port
- LPT1 (or PRN) - first parallel printer
- LPT2 - second parallel printer
- LPT3 - third parallel printer
- NUL - nonexistent device for application testing
- #Directory: A file used by DOS to keep track of files and subdirectories. The
- directory contains the names of files, their size (in bytes), the time and date
- they were last written and the names of any subdirectories. The DIR (Directory)
- command displays directory information.
-
- See also CURRENT DIRECTORY, DIRECTORY PATH and SUBDIRECTORY.
- #Directory Path: A series of directory names which tell DOS where to find a
- particular directory. The directory path begins with the name of a subdirectory
- of the current directory, or with the root directory (indicated with a "\").
- The last directory in the directory path is the directory to be used.
-
- The maximum length of a directory path, (including \ characters) is 63
- characters.
-
- If a directory path is followed by a filename, you must place a \ between the
- last directory name and the filename.
-
- EXAMPLES:
-
- \BUDGET\DATA\MYFILE.DAT - specifies that the file MYFILE.DAT is to be used.
- MYFILE.DAT is in the DATA directory. DATA is a subdirectory of the BUDGET
- directory. BUDGET is a subdirectory of the root (\) directory.
-
- DATA\MYFILE.DAT - specifies that the file MYFILE.DAT is to be used. MYFILE.DAT
- is in the DATA directory. DATA is a subdirectory of the current directory.
- #DOS: Disk Operating System. DOS provides the instructions necessary for the
- computer to operate. It also contains a set of utility tools (Commands, the
- Batch Facility, Special Keyboard keys and others) which allow you organize and
- manage your applications.
- #Drive Letter: A letter which identifies a disk drive to DOS. Each drive is
- assigned a drive letter. On a single drive system, the drive is assigned "A".
- On a two drive system the left drive is "A" and the right drive is "B". A fixed
- drive is known as "C".
- #End-Of-File-Marker: A special ASCII code used by DOS to denote the end of a
- file. This character is Ctrl-Z (Hex 1A).
- #Exit Code: A numeric value produced by some DOS commands which indicates what
- occurred during the command's execution. This is useful in batch files to
- allow action to be taken based upon the success or failure of a command. For
- example, the RESTORE command has these exit codes:
-
- 0 - Normal completion 3 - Terminated by user
- 1 - No files found to restore 4 - Terminated due to error
-
- When the RESTORE command finishes, it sets the ERRORLEVEL variable to the exit
- code value. The Batch Subcommand IF may then be used to test the value of
- ERRORLEVEL and take appropriate action.
- #External Command: A DOS command that resides in a disk file. DOS has
- "internal" and "external" commands. Internal commands are stored in memory and
- can be executed even if a diskette containing DOS is not in use. To execute an
- external command, a disk containing the command file must be in use. The
- filenames of external commands are the same as the name of the command. The
- filename extensions are either COM or EXE. For example, the FORMAT command is
- stored on the DOS diskette as FORMAT.COM. The SORT command is stored as
- SORT.EXE.
-
- See also INTERNAL COMMAND.