Besides scheduling TPs in response to inbound requests, APPC/MVS also allows for inbound requests to be routed to an APPC/MVS server.
An APPC/MVS server is an MVS™ application that uses the Receive_Allocate callable service to receive inbound conversation requests directly (rather than through a transaction scheduler). APPC/MVS servers avoid the overhead associated with APPC/MVS scheduling. See Figure 1 for an example.
Because APPC/MVS servers can process multiple inbound conversations concurrently, a single server address space might contain multiple interleaved (or overlapping) conversations concurrently.
Figure 1. Example of
APPC/MVS server processing
- Represents possible events in the life of a server address space. Items 2 and 3 correspond with these events.
- Points at which SMF writes the type 30 (subtypes 1, 2, 3, 4, and 5) record. INIT represents initialization and TERM represents termination.
- Points at which SMF writes type 33 (subtype 2) records to reflect individual conversations within a server address space. RECEIVE ALLOCATE represents the start of conversation activity and DEALLOCATE represents conversation deallocation.