All inbound transactions require a scheduler and are scheduled as follows:
z/OS – in z/OS, the ASCH address space schedules inbound transactions in initiators under its control. The ASCH use of initiators is similar to that of JES (Job Entry Subsystem), which schedules jobs in initiators under its control.
IMS TM – in IMS TM, the Control region schedules inbound transactions using message regions under its control. The Control region use of message regions is similar to the ASCH use of initiators.
CICS – CICS schedules inbound transactions as tasks within its own address space. CICS differs from z/OS and IMS TM in that it does not schedule transactions in a separate address space.
Outbound transactions are handled as follows:
z/OS – outbound transaction names are mapped to an SNA logical unit using a file called the Side Information File.
IMS TM – outbound transaction names are mapped to an SNA logical unit using a file called the Side Information File.
CICS – for CPI-C, transaction names are mapped through the PARTNER table, which is set up using the Resource Definition Online (RDO) facility.
LU 6.2 uses connection and session tables and the RDO facility.
