Each installation requires at least one copy of each of the MVS™ System Messages documents and of z/OS MVS Dump Output Messages. Regardless of the specific options of your system, you will receive at the console or in listings some subset of the messages in these documents.
Each installation also requires at least one copy of z/OS MVS System Codes, which contains the 3-digit hexadecimal system completion codes (abend codes) and the wait state codes produced by all the components of the system.
All programming and operations personnel need access to the basic documents, although application programmers might not need to have their own copies.