Enabling IMS ETO for ACF/VTAM terminals

IMS Extended Terminal Option (IMS ETO) requires at least one user descriptor and one logon descriptor.

ETO descriptors
When you are enabling ETO support in your installation, you can optionally request that IMS produce ETO descriptors during system definition. You do this with the ETOFEAT keyword in the IMSCTRL macro.
Logon descriptors
Logon descriptors provide IMS with information about the physical characteristics of the terminals that establish logon sessions.
MFS device descriptors
Use MFS device descriptors to define characteristics of terminals added dynamically that have different characteristics from statically defined terminals.
MSC descriptors
MSC descriptors relate remote NAME macros to MSC links defined during system definition.
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.
Specifying the number of hash table slots
The number of hash table slots that IMS builds for a statically defined resource depends on the total number of resources; you can specify additional slots.

Parent topic: Tailoring the IMS system to your environment

Related reference

DFSDSCMx member of the IMS PROCLIB data set
DFSDSCTy member of the IMS PROCLIB data set