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:

After the initial DFHPSD macro, you define each partition (screen area) with a DFHPDI macro. DFHPDI specifies:

You end the partition set with a second DFHPSD macro, containing only the option TYPE=FINAL. See the CICS Application Programming Reference manual.

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.

3290 character size

The 3290 hardware allows you to use up to eight different character sets, of different sizes. Two sets come with the hardware; the others can be loaded with a terminal control SEND command. (Refer to the IBM® 3290 Information Display Panel Description and Reference manual for details.)

Each character occupies a rectangular cell on the screen. Cell size determines how many lines and columns fit on the screen, or in a particular partition of the screen, because you can specify cell size by partition. Cells are measured in pels (picture elements), both vertically and horizontally. The smallest cell allowed is 12 vertical pels by 6 horizontal pels. The 3290 screen is 750 pels high and 960 pels wide. Using the minimum cell size, therefore, you can fit 62 characters vertically (that is, have 62 lines), and 160 characters horizontally (for 160 columns). (The 3290 always selects the character set that best fits your cell size, and places the character at the top left corner of the cell.)

Partition sizes are expressed in lines and columns, based on the cell size you specify for the partition, which is expressed in pels. (The name of the option is CHARSZE, but it is really cell size.) To make sure your partitions fit on the screen, you need to work out your allocation in pels, although BMS tells you when you assemble if your partitions overlap or does not fit on the screen. The partition height is the product of the number of rows in the partition and the vertical CHARSZE dimension; the partition width is the product of the number of columns and the horizontal CHARSZE value.

If you do not specify a CHARSZE size in your DFHPDI partition definition, BMS uses the default given in the DFHPSD partition set definition. If DFHPSD does not specify CHARSZE either, BMS uses the default established for the terminal when it was installed. If you specify cell size for some but not all partitions, you must specify a default for the partition set too, so that you do not mix your choices with the installation default.

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