Advanced Debugging System for CICS

"The First Name in CICS Debugging"    

Storage Fetch Protection    

The purpose of most on-line CICS debuggers is to provide a degree of safety by checking each monitored instruction to prevent storage violations. ADS takes this one crucial step further.

Many errors go undetected for long periods of time because instructions incorrectly fetch storage without causing any immediate damage. For example:

CLC   FIELDA,0

Here, FIELDA is being compared to the data at storage address zero, when the intention was to compare it for the constant value zero.

Such mistakes, in ALC coding, are not picked up by the Assembler. Worse, they can go unnoticed for years, resulting in untraceable damage. High-Level languages, such as COBOL or C/370 are subject to similar problems in a CICS environment for different reasons. It's not uncommon for an incorrectly addressed area to be moved and written to a file without attempting any damage to the CICS environment. CICS Storage isolation does not prevent or detect these errors, and neither do most of the other popular debugging products.

How to tell if your current debugger has this feature.

Add a statement to one of your COBOL programs, similar to the following:

MOVE DFHCOMMAREA TO WS-FIELD.

If your application doesn't have a COMMAREA, you should get an error message which prevents the MOVE from executing.