Partition definition

Each partitioning of a screen is defined by a partition set, which is a collection of screen areas (partitions) intended for display together on a screen.

You define a partition set with assembler macros, just as you do map sets. There are two of them: DFHPSD and DFHPDI.

The partition set definition begins with a DFHPSD (partition set definition) macro, which defines:
  • The name of the partition set
  • Screen size (BMS makes sure that the partition viewports do not exceed the total space available)
  • Default character cell size (we talk about cell size in 3290 character size)
  • The partition set suffix, used to associate the partition set with a particular screen size (see Establishing partitioning)
After the initial DFHPSD macro, you define each partition (screen area) with a DFHPDI macro. DFHPDI specifies:
  • The identifier of the partition within the partition set.
  • Where the partition is located on the screen.
  • Its viewport size (in lines and columns).
  • The presentation space associated with the viewport (that is, the amount of buffer space allocated), also in lines and columns. Because scrolling is strictly vertical, BMS requires that the width of the presentation space match the width of the viewport.
  • The character size to be used.
  • The map set suffix associated with the partition, used to select the map set appropriate for the partition size.
  • Whether the partition may receive CICS® error messages (BMS sends certain error messages that it generates to a partition so designated, if there is one).
You end the partition set with a second DFHPSD macro, containing only the option TYPE=FINAL. See DFHPSD .

Because these are assembler macros, you need to follow assembler format rules in creating them. See Writing BMS macros if you are not familiar with assembler language. After you do, you need to assemble and link-edit your partition set. The resulting load module can be placed in the same library as your map sets, or in a separate library if your installation prefers. Your systems staff also need to define each partition set to the system with a PARTITION definition.