Using distributed presentation management (DPM)

With distributed presentation management (DPM), formatting functions usually performed by MFS are distributed between MFS and a user-written program for SLU P devices or ISC nodes. If the 3790 or FIN controller has previously been defined to IMS by unit number, some changes must be made to convert to DPM.

With DPM, the physical terminal characteristics of the secondary logical unit do not have to be defined to MFS. MFS has to format only the messages for transmission to the user program in the remote controller or ISC node, which must assume responsibility for completing the device formatting, if necessary, and present the data to the physical device it selects.

For remote programs using DPM, the data stream passing between MFS and the remote programs can be device independent. The messages from the IMS application program can include some device control characters. If so, the IMS application program and the data stream to the remote program might lose their device independence.

If IMS is to communicate with other subsystems (such as IMS, CICS® or user-written), the other subsystem must be defined as an ISC subsystem. Definitions for ISC must:

• Specify MFS operation as DPM-Bn, where Bn is a user-assigned number (B1 through B15).
• Define TYPE:LUTYPE6 on the TERMINAL macro during system definition.

DPM with ISC provides:

• Output paging on demand that allows paging to be distributed between IMS and another system
• Automatically paged output that allows MFS pages to be transmitted to another system without intervening paging requests
• Transaction routing that allows application programs to view the routing information when it is provided in the input message