There are many reasons why you might get the wrong data displayed, some with system-related causes and some with application-related causes. If you think that it is system-related, read this section for some suggestions on likely areas in which to start your investigations.
For the present purpose, a terminal is considered to be any device where data can be displayed. It might be some unit with a screen, or it could be a printer. Many other types of terminals are recognized by CICS®, including remote CICS regions, batch regions, IMS™ regions and so on, but they are not considered in this section on incorrect output.
Broadly, there are two types of incorrect output that you might get on a screen, or on a printer:
In practice, you may sometimes find it difficult to distinguish between incorrect data information and incorrect formatting. In fact, you seldom need to make this classification when you are debugging this type of problem.
Sometimes, you might find that a transaction runs satisfactorily at one terminal, but fails to give the correct output on another. This is probably due to the different characteristics of the different terminals, and you should find the answer to the problem in the sections that follow.
Before you can investigate the reasons why incorrect output is displayed at a terminal, you need to gather some information about the transaction running at the terminal, and the about terminal itself.
The first things you need to know are:
Depending on the symptoms you have experienced, you probably need to examine the PROFILE definitions for the transaction, and the TYPETERM definitions for the affected terminal. The attributes most likely to be of interest are SCRNSIZE for the PROFILE, and ALTSCREEN, ALTPAGE, PAGESIZE, EXTENDEDDS, and QUERY for TYPETERM. Other attributes might also be significant, but the values you find for the attributes named here can often explain why the incorrect output was obtained.
Amongst the debugging tools you have, two are likely to be of particular use for investigating terminal incorrect output errors in a VTAM environment. They are:
For information on using tracing in CICS problem determination, see Using traces in problem determination.