Basic mapping support (BMS) is an application programming interface between terminal devices and CICS programs. BMS provides three assembler language macro instructions (macros) for defining MAPs.

BMS is a separate interface where BMS macros are assembler macros used to define MAPs. Designing MAPs by coding BMS macros is still widely used in various real-time applications.

However, there are other products for creating MAPs with additional facilities of display terminal to make the MAP creation process easier. The tools produce the BMS macros and the layout without having the programming effort.

Screen Definition Facility II (SDF II) is the one among the tools and allows to build screens directly from a display station, testing the appearance and usability as required.

The screen designed by using BMS Macros is called as MAP and one or more of MAPs grouped together create MAPSET. The three assembler macros used to define BMS maps are -

Macro Full form Description
DFHMDF Define field hierarchy map definition field Defines an individual field on a screen or page
DFHMDI Define field hierarchy map definition interface Defines a single map as a collection of fields
DFHMSD Define field hierarchy map set definition Groups single maps into a map set

Advantages -

  • BMS removes device dependencies from the application program.
  • It converts incoming device-dependent data into device-independent format.
  • It understands device-independent output commands and produces device-dependent data streams for specific terminals.
  • These features eliminate the need to learn complex device data streams.
  • Allows to use the same program for various devices, because BMS determines the device information from the terminal definition not from the application program.
  • BMS separates the design and preparation of formats from application logic, reducing the impact of one on the other.