BMS Map Definitions

Before a program can SEND or RECEIVE a screen, its BMS mapset must be assembled into a load module and defined to CICS with a MAPSET definition.

From BMS source to a running map

• You code the map in BMS macros: DFHMSD for the mapset, DFHMDI for each map, DFHMDF for each field.
• The source is assembled twice - once for the physical map (screen layout) and once for the symbolic map (the COBOL copybook your program uses).
• TYPE=MAP with MODE=INOUT builds the physical map; TYPE=DSECT with LANG=COBOL builds the symbolic DSECT.
• The assembled physical map becomes a load module in a load library on the DFHRPL concatenation.
• PARTITIONSET definitions are the same idea for partitioned screen sets - rarely needed today.

The MAPSET definition

• MAPSET - the 1 to 8 character name of the assembled mapset load module.
• STATUS(ENABLED) makes the maps usable; DISABLED blocks them.
• RESIDENT(YES) keeps the mapset in storage; NO loads it on demand - fine for most maps.
• USAGE(NORMAL) is the standard; other values exist for special device support.
• Like programs, mapsets are refreshed with NEWCOPY after reassembly.

Assembling a mapset

• Assemble with the high-level assembler, using &SYSPARM to pick MAP or DSECT in one source member.
• Put the load module where CICS can find it, define the MAPSET, and install the group.

Example - assemble skeleton and define the mapset: