As I discussed in part 1 of this series (a link to part 1 is at end of this article), data queues offer a brilliant method of program-to-program communication. The Distributed Data Management (DDM) type of data queues offer a way to extend this capacity to include system-to-system communication.
In the past, DDM data queues, originally based on the SNA facility, were often challenging to configure, especially as TCP/IP became the preferred communication protocol. But with the introduction of relational database (RDB)–based identification of a remote system, this challenge was dramatically reduced.
In this article, I discuss DDM data queues, and I also add to my collection of “missing” data queue CL commands, presenting the Copy Data Queue Description (CPYDTAQD) command.
Let’s start with DDM data queues. DDM data queues offer a convenient way to let two applications on different System i computers communicate with each other.