Rexx Programmer's Reference

Chapter 29. IBM Mainframe Rexx

Overview

IBM bundles Rexx with all its mainframe operating systems. These include operating systems in what we generically refer to as the VM, OS, and VSE families. IBM mainframe Rexx is not an open-source product but rather is bundled with commercial mainframe operating systems. The name of the product is typically written in uppercase, as REXX. For consistency, we'll continue to refer to it as we have previously in this book, as Rexx.

Mainframe Rexx is important for several reasons. Rexx was originally offered on the mainframe (specifically for VM/CMS). VM influenced early development of the language, leaving its imprint in various ways. For example, the stack is a VM/CMS feature, and many VM/CMS commands send their output to the stack. The stack remains a popular means for command I/O in Rexx today, and the free Rexx interpreters support the stack in this role.

Another important reason to discuss mainframe Rexx is the key role mainframes continue to play in many IT organizations. While the mainframe has a low profile in the trade press and in industry buzz, thousands of sites worldwide continue to rely on mainframes for their most vital business operations. Mainframes remain critical to organizations around the world. Rexx is the predominant mainframe scripting language. No other scripting language comes anywhere close to Rexx's usage level on the mainframe.

Many readers will face the prospect of porting Rexx code from the mainframe to other platforms. ...