Defining and customizing TSO/VTAM time sharing

The following is an overview of the steps you must perform to define TSO/E to VTAM®:

Define the primary TSO/E address space and TSO/E user address spaces to VTAM. For more information, see Defining TSO/E address spaces to VTAM.
Write a procedure to start TSO/E and include it in a procedure library. For more information, see Writing the procedure that starts TSO/VTAM time sharing.

The following steps are optional:

Tailor the session protocols, or rules, VTAM uses to start a session between a terminal and TSO/E. For more information, see Tailoring VTAM session protocols.
Define the TSO/E LOGON command to VTAM. See Defining the LOGON command to VTAM for more information.
Create SYS1.PARMLIB member TSOKEY00, or an installation-defined alternate member, to override the default values that are used to start TSO/VTAM. For more information, see .
If you plan to use the TSO/E Session Manager, see SYS1.PARMLIB changes about changes you may need to make to the SYS1.PARMLIB member to support a Session Manager environment.
Build translation tables for your installation's requirements. For more information, see Building translation tables for TSO/VTAM users.
Write VTAM exit routines to customize the connection between TSO/E and VTAM. For example, you can write exit routines to:
- Tailor default logon error messages
- Set the terminal type and buffer size
- Support terminals not supported by IBM®
- Modify the way attention interrupts are handled. You may want to intercept and suppress attention interruptions that interfere with important processing.

Before a user can log on to TSO/E, both VTAM and the terminal control address space (TCAS) must be active in the system. The system operator enters the START command to start VTAM. After VTAM has been started, the system operator enters the START command to start TSO/E and activate TCAS. TCAS accepts logons from TSO/VTAM users and creates an address space for each user.

When a user logs on, the VTAM terminal I/O coordinator (VTIOC) is initialized. VTIOC controls the movement of data between TSO/E and VTAM. SYS1.PARMLIB member TSOKEY00 or an installation-defined alternate member contains parameters that are used during VTIOC initialization. If a member other than TSOKEY00 is used, the operator must include the member name either on the START command or in the procedure that the START command invokes. For a description of TSOKEY00, see .

The system operator uses the MODIFY command to modify TSO/VTAM and the STOP command to stop TSO/VTAM. For more information on the START, MODIFY, and STOP commands and how they pertain to TSO/VTAM time sharing, see .