Some of the services included in this information are not authorized, but are included because they are of greater interest to the system programmer than to the general applications programmer. The functions of these services are of such a nature that their use should be limited to programmers who write authorized programs. Services are also included if they have one or more authorized parameters; in other words, parameters that are available only to authorized programs.
This information is for the programmer who is using assembler language to code a systems program, and who needs to become familiar with the MVS operating system and the services that programs running under it can invoke.
Programmers using this information should have a knowledge of the computer, as described in z/Architecture®: Principles of Operation, as well as a knowledge of assembler language programming.