Segmentation in text applications

Segmentation concerns how a program interacts with its environment before issuing a converse statement.

By default a program that presents text forms is non-segmented, which means that the program behaves as if it were always in memory and providing a service to only one user. The following rules are in effect before a non-segmented program issues a converse statement:

A called program is always non-segmented.

A non-segmented program can be easier to code. For example, you do not need to reacquire a lock on an SQL row after a converse. Disadvantages include the fact that SQL rows are held during user think time, a behavior that leads to performance problems for other users who need to access the same SQL row.

Two techniques are available for releasing or refreshing resources before a converse in a non-segmented program:
The benefit of using a segmented program on IMS™ or CICS® for z/OS® is as follows:

The benefit of using a non-segmented program on IMS or CICS for z/OS is that the response time for each user is less than for a segmented program because program state is not saved and restored.

For additional details that are meaningful for IMS and CICS COBOL programs, see Behavior of a segmented program on CICS and IMS.

Related concepts
Behavior of a segmented program on CICS or IMS
Program part

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