What you need to install High Level Assembler

This section identifies the system requirements for installing High Level Assembler. You need to plan for two different system environments:

Target system—the system comprising the set of libraries that are updated by SMP/E and system utilities during installation
Driving system—the system on which the jobs are run to install the program

The machine-readable components for High Level Assembler are installed in target and distribution libraries.

Target libraries are the data sets in which the run-time copy of High Level Assembler is stored. These data sets include the executable program code and any other components used during execution, such as sample JCL and messages.
Distribution libraries are the data sets in which additional copies of these components are stored. The copy of High Level Assembler kept in the distribution libraries can be kept at a different service level than that in the target libraries. SMP/E can reconstruct the target libraries in whole or in part from the distribution libraries. Therefore, service or user modifications can be removed from the run-time copy of High Level Assembler

In many cases, the same system can be used as both a driving system and a target system. However, you may want to set up a clone of your system to use as a target system by making a separate IPL-able copy of the running system. The clone should include copies of all system libraries that SMP/E updates, copies of the SMP/E CSI data sets that describe the system libraries, and your PARMLIB and PROCLIB.

Some cases where two systems should be used include the following:

When installing a new level of a product that is already installed, the new product will delete the old one. By installing onto a separate target system, you can test the new product while still keeping the old one in production.
When installing a product that shares libraries or load modules with other products, the installation can disrupt the other products. Installing onto a test system or clone will allow you to assess these impacts without disrupting your production system.