Restrictions on Distributed Program Linking

There are certain restrictions on the types of program to which you can link using the distributed program linking feature of MSS.

You cannot link to programs that:

• Issue terminal control commands from a connected system back to MSS.
• Inquire on terminal attributes.
• Issue BMS commands.
• Issue data interchange commands.
• Address the TWA or the TCTUA. You must use the COMMAREA to pass data between systems, or you might get unpredictable results.
• Issue syncpoints. DPL incorporates only sync level 1 logic. Whether you have single or multiple connected systems, a sync request can be propagated through all the connected systems. You should therefore take syncpoints from your system and not the invoked end of the link, otherwise you might get unpredictable results.

In addition to these restrictions, you should also be aware that when you are accessing DB2 from a transaction running on MSS, security access to the DB2 application plan is based on the transaction ID under which the program runs. The default transaction ID is one of the mirror transactions CPMI, CSMI and CVMI. To enable greater selectivity for DB2 application plans, you can specify an alternative transaction ID in either the PCT entry or in the EXEC CICS LINK command. This transaction muct be defined in the target system and must point to the mirror program DFHZCSMI. In all other respects (such as security attributes and task priority), the mirror transaction operates normally.