Overview of the Extended Terminal Option

The Extended Terminal Option (ETO) of IMS allows you to add VTAM® and ISC TCP/IP terminals and users to your IMS without predefining them during system definition.

ETO is part of the IMS Transaction Manager (TM), and provides additional features for users, such as output security, automatic logoff, and automatic signoff.

This topic provides system programmers with the conceptual information that is required to implement and administer ETO. Read the information in this topic if you are unfamiliar with ETO.

Note: ETO is required to define dynamic TCPIP terminals for ISC. However, ETO is primarily used with VTAM terminals. Although some information in the following topics applies to dynamically defined ISC TCP/IP terminals, most of the topics about ETO describe ETO concepts and administration as they relate to VTAM only.

Benefits of using ETO

ETO adds essentially two major enhancements to the Transaction Manager environment. With ETO:
  • Users can obtain IMS sessions with VTAM or ISC TCP/IP terminals that have not been defined to IMS during system definition.
  • Output messages that are destined for particular users are secure, and they reach only those users.
In addition, by installing ETO, you can achieve each of the following:
  • Improved system availability by reducing scheduled down time associated with adding or deleting VTAM and ISC TCP/IP terminals.
  • Faster system availability to users, because they can establish an IMS session from any VTAM and ISC TCP/IP terminal in the network.
  • Improved IMS security by relating output messages to users, rather than to terminals.
  • Reduced number of macros required to define the terminal network. This reduces system definition time and storage requirements.
  • Reduced checkpoint and restart time. For ETO terminals and user structures, resources are not allocated until they are actually required; similarly, when they are no longer required, they are deleted.
  • Reduced number of skilled system programmer resources that are required for maintaining static terminal definitions.