Program ..............:  VOL.PAS
Version ..............:  1.01
Implementation .......:  Turbo Pascal v4.x, v5.x
Author ...............:  Vernon E. Davis
                      :  17 South Centre Street
                      :  Merchantville, NJ 08109
                      :  CompuServe [71330,2705]
References ...........:  MS-DOS Encyclopedia (Microsoft Press)
Purpose ..............:  To allow the manipulation of
                      :  MS-DOS Disk Volume Labels.
Type Declarations ....:  Two User Types Defined ...
                      :  TYPE  Drive = Byte;
                      :    The value of Drive corresponds to disk location.
                      :    ( 1 = A:   2 = B:   3 = C:   4 = D:  etc. )
                      :  TYPE  VolumeName  = String[11];
                      :    Spaces allowed. Functions do not check for
                      :    invalid characters other than period ( . ).
                      :    Functions do convert all input to uppercase.
Function Declarations :  Four Functions Available ...

   Function ADDVOL(Drive; VolumeName) : Boolean;
      This function allows the addition of a New Volume Label on
      a disk that does not have one.
      Returns:
         FALSE if
           1. Drive is less than 1 ( A: ) or greater than 26 ( Z: ).
           2. Drive is an invalid specification.
           3. Volume Label already exists.
           4. Error in adding New Volume Label.
         TRUE if
           1. New Volume Label has been added.

   Function CHGVOL(Drive; VolumeName) : Boolean;
      This function changes the current Volume Label to that of the
      New Volume Label.
      Returns:
         FALSE if
           1. Drive is less than 1 ( A: ) or greater than 26 ( Z: ).
           2. Drive is an invalid specification.
           3. No Volume Label exists.
           4. Error in changing Volume Label.
         TRUE if
           1. Volume Label has been changed.

   Function DELVOL(Drive) : Boolean;
      This function allows the deletion of a Volume Label.
      Returns:
         FALSE if
           1. Drive is less than 1 ( A: ) or greater than 26 ( Z: ).
           2. Drive is an invalid specification.
           3. No Volume Label exists.
           4. Error in deleting Volume Label.
         TRUE if
           1. Volume Label has been deleted.

   Function GETVOL(Drive) : VolumeName;
      This function returns the Volume Label string.
      Returns:
         NULL if
           1. Drive is less than 1 ( A: ) or greater than 26 ( Z: ).
           2. Drive is an invalid specification.
           3. No Volume Label exists.
           4. Error in reading Volume Label.
         !NULL if
           1. Volume Label has been read.

See the accompanying program, VOLTEST.PAS, for actual code.