Session Functions

While working at the terminal, you are communicating with TSO/E and Session Manager. In addition, you can receive messages from other TSO/E users, the operator, and from jobs you're executing. These three means of communication (TSO/E, Session Manager, and messages) are called session functions. The session functions receive the input you enter at the keyboard and generate output to you. Session Manager places the input and output in streams, either the default streams or the streams that you specify on the CHANGE.FUNCTION command.

TSO/E has an input and an output stream:

TSOIN is the input stream for the TSO/E function. Information placed in this stream is interpreted as TSO/E commands or input to programs. While a command is executing in this stream, Session Manager highlights it. Otherwise, when the command has completed execution, it is displayed at normal intensity.
TSOOUT is the output stream for the TSO/E function. All output generated by the TSO/E commands and programs is placed in this stream. The TSOOUT stream also contains a copy of the TSO/E commands from the TSOIN stream, thus creating a complete record of your TSO/E session. (The commands from the TSOIN stream appear highlighted in this stream.) In addition, the MESSAGE (MSG) function places in the TSOOUT stream any messages you receive from other TSO/E users, the operator, or from background jobs. As a result, the messages are interleaved with the TSO/E session input and output.