        MDEXTERN.COM                                       Version 1.01
        ============                                      (Februar 1998)


        MDEXTERN revectors the DOS-interrupt for the MKDIR-command to
        an external program. The desired directory name must be provided
        as a command line parameter to the external program.
        A suitable utility is BSE's ATMD.COM, which is not included in
        this distribution.



        Why we need MDEXTERN
        --------------------

        The Portfolio's MKDIR command causes a "Divide by zero"-Error
        when applied on a drive with a cluster size of more than one
        sector.

        The program MKDIRFIX.COM (version 1.00) can solve this problem
        only partially:

          The creation of a subdirectory in a subdirectory fails
          whenever the name entry in the parent directory would
          occupy a new sector. This is the case every 16 entries.

        MKDIRFIX is a patch which reduces the Zip-drive's cluster size
        to 1 sector while the MKDIR command is active. Unfortunately,
        this will lead to a crash in the described case.
        It's safer to use MDEXTERN together with ATMD instead.



        Installation
        ------------

        MDEXTERN is a memory resident program (TSR) that needs to
        be run only once, e.g. in AUTOEXEC.BAT. It requires 624 bytes
        of memory after its installation.

        Syntax:   MDEXTERN <program name>

        The external program must be provided with complete path, name
        and extension (max. 60 characters). To enable quick access, it
        should be located on a ram card or ram disk.

        Example:  MDEXTERN c:\utils\atmd.com

        The MD-command calls the external program if the cluster size
        of the affected drive is more than 1 sector.



        Deinstallation
        --------------

        To remove MDEXTERN from memory, type:

                  MDEXTERN /R

        The deinstallation is only possible as long as no other TSRs
        have manipulated the interrupt vector 21hex later. These would
        have to be deinstalled first.



        Known bugs
        ----------

        The parameter supplied to the MD command is limited to 80
        characters. This limit has been set because there must be
        reserved some memory for the parameter permanently.

        Updates might be available on this Web-page:

        http://leute.server.de/peichl/pofozip.htm
