3290 information panel in partitioned format mode

The screen of the 3290 can be divided into several rectangular areas called partitions. Depending on LPAGE/DPAGE selection, each logical page of an output message is sent to the partition specified on the DPAGE statement.

When the 3290 is operating in partitioned mode, the usual control block linkages are in effect. There are, however, additional functions, because the logical pages described in the MOD can be sent to different partitions. The partition descriptor block (PDB) is a type of intermediate text block (ITB). The PDB describes the set of partitions that can appear on the screen in response to a single output message. Among other things, the PDB contains one partition definition statement coded with a partition descriptor (PD) for each partition. Taken together, the PDs define a partition set.

The linkages work as follows:

1. A MOD is requested for a particular message. The MOD names an FMT and becomes associated with the appropriate DEV statement—in this case, the DEV statement for the 3290. A DOF is created to format the 3290 for the message.
2. The DEV statement itself names a PDB. Thus the MOD is linked to the DOF, which in turn links to the PDB through the DEV statement for the 3290. This linkage gives the logical pages of the MOD (defined by the LPAGE statements) access to the PDs in the PDB.
3. Each LPAGE statement in the MOD names a DPAGE statement in the DOF.
4. For the 3290 with partitioning, a DPAGE statement contains a PD keyword, which identifies one of the partition descriptors in the PDB.

Because of this linkage, each logical page is associated with its appropriate partition that is described by a partition descriptor. When the logical page is retrieved from the message queue, it is sent to that partition.

Figure 1. Linkages in partitioned format mode