MFS Distributed Presentation Management (DPM) messages

An IMS MFS DPM message can consist of either single or multiple SNA chains as indicated within the ATTACH parameters.

For MFS DPM input or output using a device format defined with the paging OPTIONS=MSG, IMS sends or receives the entire message as a single chain of one or more related transmissions. For MFS DPM output using a device format defined with paging OPTIONS=DPAGE or PPAGE, IMS sends each logical or presentation page as a single chain of one or more related transmissions.

MFS output DPM format definitions also allow options for paged output (OPTIONS=PPAGE or DPAGE) to be sent as demand-paged or autopaged. Demand-paged output requires paging requests to the other half session for each output page. Autopaged output is sent as a series of consecutive pages (chains) with no paging requests to the other half session.

MFS DPM input using a device format defined with the paging OPTIONS=DPAGE allows IMS to optionally receive each logical page as a single chain of one or more related transmissions. All chains of autopaged input (multiple logical pages as multiple related input chains) are received consecutively without paging requests by IMS.

FM headers can occur as part of the first or only transmission of each input or output chain of the message.