APPC/MVS is an implementation of IBM's Advanced Program-to-Program Communication (APPC) in the MVS operating SYSTEM. APPC/MVS allows MVS application programs to communicate on a peer-to-peer basis with other application programs on the same MVS SYSTEM, different MVS systems, or different operating SYSTEMs (including OS/2, OS/400 and VM) in an SNA network. These communicating programs, known as transaction programs, together form cooperative processing applications that can exploit the strengths of different computer architectures.

Transaction programs can be scheduled on MVS by the APPC/MVS transaction scheduler or by an alternative transaction scheduler. This book documents the services that an alternative transaction scheduler must issue to interact with APPC/MVS. These services are callable from high-level or assembler language programs that are running in supervisor state or with PSW key 0-7.