There are two types of language processor environments; environments that are integrated into TSO/E and environments that are not integrated into TSO/E. If an environment is integrated into TSO/E, REXX execs that run in the environment can use TSO/E commands and services. If an environment is not integrated into TSO/E, execs that run in the environment cannot use TSO/E commands and services.

When a language processor environment is automatically initialized in the TSO/E address space, the environment is integrated into TSO/E. When an environment is automatically initialized in a non-TSO/E address space, the environment is not integrated into TSO/E. Environments that are initialized in non-TSO/E address spaces cannot be integrated into TSO/E. Environments that are initialized in the TSO/E address space may or may not be integrated into TSO/E.

Many TSO/E customizing routines and services are only available to language processor environments that are not integrated into TSO/E. Types of environments - integrated and not integrated into TSO/E describes the types of language processor environments in more detail.