Mainframe, MVS and zOS Discussion

Hi,

In CICS, how we define a program as asynchronous or in synchronous mode in CICS? Is it some way of programming or CICS identify whether the program is called in asynchronous or in synchronous mode its own?

Regards

First, asynchronous / synchronous coding refers ONLY to CICS intersystem communications (ISC) and not terminal-based transactions. Hence it is only needed when the program needs to connect to another system, either in the company or to another company's system. You don't define programs to be asynchronous or synchronous.

Second, if the connection is TCP/IP then it is asynchronous -- period. Synchronous programs require SNA connections.

Third, if the program uses EXEC CICS SEND and EXEC CICS RECEIVE commands, it is synchronous; if it uses EXEC CICS START and EXEC CICS RETRIEVE then it is asynchronous.

The determination of synchronous / asynchronous is made by the system support group in conjunction with the application development group and depends entirely upon the specifics of the situation. From a practical standpoint for existing code, you can look at the API calls to figure out if it is asynchronous or not.