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Benefits of APPC/MVS for Application Programs z/OS MVS Programming: Writing Transaction Programs for APPC/MVS SA23-1397-00 |
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Many types of applications are good candidates for using APPC/MVS services. The most obvious candidates are applications that need to link MVS functions or data with processing done on other computers in an SNA network. When an MVS program must communicate with a program on another system, APPC/MVS can provide a temporary connection, freeing you from having to make a permanent connection between the programs or create a special access method. A prime example of a cooperative processing application involving APPC/MVS is one in which a transaction program on an z/OS server provides z/OS services and data to a user interface program on a workstation. For example, a database-accessing program on MVS could receive requests from a partner program on the workstation, access an MVS database, perform intensive computations, and send results back to the partner program. This cooperative application would combine the usability of the workstation, with its end-user interface features such as graphics and windows, with the processing power and resources of the z/OS server. The APPC/MVS part of an APPC cooperative application—an APPC/MVS
transaction program (TP)—is any program in any address space on MVS
that issues APPC/MVS or CPI Communications calls. The TP can run in task or
SRB mode and can use other MVS services. A TP can also:
An APPC/MVS application can be a powerful adjunct to existing subsystems
and environments such as TSO/E, IMS, CICS and DB2. An APPC/MVS application
can create or access the following types of data:
APPC/MVS TPs may also participate in resource recovery by using the CPI Communications or MVS Commit or Backout services to synchronize changes with partner TPs. In addition, APPC/MVS applications can use MVS facilities such as shared data spaces, hiperspaces or look-aside techniques to enhance performance and sharing of data across APPC/MVS transactions. With this capacity for joining high-end data processing with end-user interfaces,
APPC/MVS lends itself to compute-intensive and I/O- and data-intensive programs
such as:
In addition to making cross-system connections, APPC/MVS presents a consistent
interface for communications within the same z/OS system. A local TP
can use APPC/MVS to hold a conversation with a partner TP that is under APPC/MVS
control on the same system. The two TPs can be either:
Before designing a new application or adapting an existing one to take advantage of APPC/MVS, it is important to understand how the parts of the application communicate; what the partners can exchange in a conversation, and how they do it. |
Copyright IBM Corporation 1990, 2014
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