The amount of storage that you need for your parameter list depends on the number and type of text units you need to describe your request to the system. At a minimum, you will need storage for the request block (S99RB), the request block extension (S99RBX), the text unit pointer list, and possibly, some of the text units.
The text units into which the system returns information must be in dynamic storage. These include information retrieval keys (described in Dynamic information retrieval text units) and some of the non-JCL dynamic allocation functions keys (described in Non-JCL dynamic allocation functions). Use the GETMAIN or STORAGE macros to obtain storage for these text units.
Text units that the system does not use to return information need not be in dynamic storage. They can be in static storage in your program.