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DFHMDI is used to define a map with its characteristic in a mapset. There can be any number of DFHMDI. Some of the important operands of DFHMDI are below:

  • SIZE

    It has two arguments namely length and breadth and as a whole the size of the map is specified here.

    SIZE = (Line,Column)

  • LINE

    The map starting line is mentioned here.


    The map-starting column within the LINE is mentioned here.

  • JUST

    RIGHT or LEFT is coded here to inform the justification of the map within mapset.

  • CTRL

    Device control requests are placed here. Multiple parameters are separated by comma. FREEKB is used to unlock the keyboard. FRSET is used to reset the MDT of all the fields in all the maps to zero. ALARM is used to set an alarm at screen display time. PRINT is used to send the mapset to printer.


    It should be ‘YES’ to reserve the prefix space of 12 bytes for BMS commands to access TIOA properly. This is required for command level CICS.


The following example shows how to code a map definition,

   LINE = 01, X
   COLUMN = 01, X

The SIZE, LINE, COLUMN, JUST parameters decides the size and location of map within map set. CTRL and TIOAPFX can be also coded in DFHMDI. but the value of DFHMDI overrides the value of DFHMSD.

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