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-
-
- XD (eXtended Directory/eXchange Directory) by Bob Abrahams.
- January, 1987
-
- This program is released to the public domain and may be used and
- distributed without restriction provided that the program and
- its associated documentation files are not sold. In using this
- program, the user agrees that the author is not liable for
- problems arising in the use of the program, whether in
- the operation of the program itself or its affect on other
- programs or operation of the computer system.
-
- ---------------------------------------
-
- XD (eXtended Directory change) COMMAND
-
- Purpose: Provides for extended Change Directory capability,
- including ability to exchange between two directories
- without specifying path each time, changing to parent
- directory without specifying entire path and defining
- and changing to directories in an abbreviated manner.
-
- Format: [d:][path]XD [d:][path] | / | * | ?
-
- Type: Internal External
- ***
-
- Remarks: Specify the parameters:
-
- [d:][path] before XD to specify the drive and path that
- contains the XD command file.
-
- [d:] to specify the drive specifier of the disk whose
- current directory you want to change or display.
-
- [path] to specify the desired directory path name. The
- path name cannot be more than 63 characters starting
- from the root directory.
-
- NOTE: Unlike the DOS CD command, XD actually changes
- the default logged drive to the drive given, if any.
-
- See notes below regarding the use of /, * and ?.
-
-
- COMMAND FORMS:
-
- In the description below, <directory> indicates a directory
- definition. If a drive is not included, the default logged drive
- is assumed. If the path does not start at the root (i.e. if it
- does not start with \), the current directory on the drive
- indicated preceeds the path given.
-
- The "current directory" refers to the drive and directory
- active when the program was started.
-
- XD <directory>
- Saves current directory and changes to indicated
- directory. If the indicated directory is the same as the one
- last saved, the last different directory remains in memory.
-
- XD
- Exchanges current directory and last saved directory. If
- the saved directory was on a different drive, the logged drive is
- also changed accordingly. This may be repeated, exchanging back
- and forth between two directories. If XD has not been
- initialized by previous use, nothing is saved, and an error
- message is displayed.
-
- XD /
- Saves current directory and changes to parent of current
- directory. (If at root directory, no change is made in directory
- or in saved directory.)
-
- XD *
- Saves current directory. May be used to initialize the XD
- resident memory section. Standard output messages are supressed.
- Not required under normal XD usage.
-
- XD ?
- Displays help screen.
-
-
- ERROR MESSAGES:
-
- Invalid directory
- This error will occur if the directory specified cannot be
- found. Possible causes include not being on the drive with the
- directory requested, not starting from the root (starting with \)
- when this is appropriate and incorrectly entering the
- parameter string. This can also occur using the XD command to
- exchange to the last saved directory if this directory had been
- removed since it was saved. When this error occurs, the
- directory is not changed and the saved directory is not changed.
-
- No directory saved
- This occurs when the XD command (without parameters) is used
- when the resident memory portion of XD has not been initialized.
- XD will automatically initialize itself the first time a
- successful change is made using the XD [directory] command or the
- XD / command, or manually, by using the XD * command. This error
- also causes display of the date and version number and prompts
- the user to use the XD ? (help) command.
-
-
- NOTES:
-
- A space is required following the program name (XD) before
- the other parameters, even if the string starts with a backslash.
- This is unlike the built-in command CD which does recognize the
- backslash as the start of the directory name. Example: In DOS
- you can enter CD\ to change to the root directory, but with XD,
- you must enter XD \, NOT XD\. This is a limitation built in to
- the COMMAND.COM command parser.
-
- To display the version and release date, use the XD ?
- command or TYPE the XD.COM file.
-
- XD saves a small amount of resident memory to save the last
- directory. This happens only the first time that XD is used
- where it can successfully save the directory, unless removed by a
- reboot or by a resident memory utility. Thereafter the same
- memory space is reused. XD should operate properly in most MS-
- DOS and PC-DOS environments (v. 2.0 and later), used before or
- after other resident programs.
-
- However, XD should not be first invoked within a shell or
- secondary COMMAND, as the memory space reserved will confuse the
- DOS memory allocation system when the user returns to the higher
- shell level. This also applies to using XD using the R command
- in WordStar or other similar applications. This may be easily
- handled by issuing an XD * command while at the highest level and
- can be insured by including an XD * command in the AUTOEXEC.BAT
- file. This makes no directory changes but does initialize the XD
- memory space. This is not necessary under most circumstances.
-
- XD displays the drive/directory in effect at the end of the
- program. It also indicates whether the directory was changed or
- whether there was no change. (There would be no change in case
- of an error, which will be indicated, or if the attempt is made
- to change to the same directory in effect when the program
- started.) This message line is suppressed for the XD * command.
- It can also be suppressed by patching the byte at location 0108h
- in the XD.COM file to 0. This may be useful if the PROMPT
- command has been used to display the drive and directory. See
- below for more patching information.
-
- XD provides for certain patchable parameters within the
- program XD.COM. These can be changed to customize the program
- somewhat. At the start of the XD.COM file, following a 3-byte
- JMP instruction, there is a string of bytes that can be changed.
- The location of each and their normal value and function are
- described in the following table. Use DEBUG or other patcher to
- make the changes desired.
-
- Address Normal Function
- (hex) value and notes
-
- 0100-0102 JMP START DO NOT CHANGE.
-
- 0103 12h Interrupt number. DO NOT CHANGE.
- 0104 0 Function number. (Future parameter.)
- 0105 '/' "Parent directory" character.
- 0106 '*' "Current directory" character.
- 0107 '?' "Help" character.
- 0108 0FFh Non-zero to show directory
- before exiting.
-