User descriptors

User descriptors are another form of descriptor created during system definition for ETO. Node user descriptors are essentially migration aids, allowing message queues and options associated with a particular terminal to remain unchanged during migration.

User descriptors are another form of descriptor created during system definition for ETO. Three types of user descriptors are:

The node user descriptors are essentially migration aids, allowing message queues and options associated with a particular terminal to remain unchanged during migration. They do not, however, provide output security.

Related reading: For information about the format of user descriptors, refer to IMS Version 15.3 Communications and Connections.

User descriptors are generated from each VTAM® TERMINAL or VTAMPOOL SUBPOOL macro statement. Those descriptors created from VTAM TERMINAL macro statements, such as node user descriptors, have the same name as the terminal. Descriptors created from VTAMPOOL SUBPOOL macro statements have the same name as the subpool.

For user descriptors created during IMS system definition from the SUBPOOL macro statement, the response option (TRANSRESP, NORESP, or FORCRESP) cannot be set. This is because the response option is defined on the TERMINAL statement for static definitions. You need to add the appropriate response option for your installation to any user descriptor created from a SUBPOOL statement.

DFSUSER descriptor

When you request that IMS build ETO descriptors, IMS creates a single default user descriptor, DFSUSER, which defines default user characteristics. The DFSUSER descriptor represents the most common set of user options. With this descriptor, IMS can dynamically create a user and message queue structure for a signon request when no other user descriptor is available. The message queue name is the same as the user ID. You can also use DFSUSER to add queue names and other options through the DFSSGNX0 Signon exit routine.

Related reading: Refer to IMS Version 15.3 Exit Routines for more information about how to use the DFSSGNX0 exit routine.

Recommendation: Use the DFSUSER descriptor for most of your users after your migration to ETO is completed.

Node user descriptors

Node user descriptors are created during system definition. One is generated for each terminal in the IMS system definition. Node user descriptors are created even if they match DFSUSER options, except for ISC terminals defined for parallel-session support.

Installation-created descriptors

Installation-created user descriptors are designed by your installation to meet your criteria. The name of the installation-created user descriptor is the same as the user ID.

User descriptor format

The format for a user descriptor, regardless of whether it is created by installation, node, or DFSUSER, is: 
U username parm1 parm2 parmn
U is the descriptor type (USER), and Username is DFSUSER, the user ID, or the node user name from the name field in the TERMINAL or SUBPOOL macro statement supplied by the installation.

parm (1...n) can be any of the following parameters: ASOT=, LTERM=, OPTIONS=, AUTLGN=, AUTLMOD=, AUTLDESC=, AUTLID=