BMS Maps

The two BMS maps

• BMS uses two maps for every screen: the physical map and the symbolic map.
• The physical map describes the screen layout for CICS at run time.
• The symbolic map describes the same fields to the COBOL program at compile time.
• Both are generated from the same mapset source, so they always agree with each other.

Physical map

• Created when the mapset is assembled with TYPE=MAP (or TYPE=&SYSPARM for both maps).
• Stored as a load module in the CICS load library.
• Contains constant text (titles, captions, instructions), field positions, lengths and attribute bytes.
• Referenced by the MAPSET name on SEND MAP and RECEIVE MAP commands.

Symbolic map

• Created when the mapset is assembled with TYPE=DSECT (or TYPE=&SYSPARM for both maps).
• Stored as a copybook member in a copy library.
• The COBOL program brings it in with a COPY statement in the Data Division.
• For every named screen field it generates a length field (suffix L), a flag field (suffix F), an attribute field (suffix A), and data fields (suffixes I and O).