When is a View/Deliver Cross-Memory (XMS) Task needed?

Document ID : KB000031433
Last Modified Date : 14/02/2018
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This document describes when a View/Deliver cross-memory XMS task should be used.

. A View/Deliver cross-memory (XMS) task is mandatory:
  . If the user interface is CICS, VTAM or IMS.
     Interface module SARTSO is executed directly for TSO, module SARSPF is executed directly for ISPF, and module 
     SARROS is executed directly for ROSCOE.


. A View/Deliver cross-memory (XMS) task is optional:
  . If the user interface is TSO, ISPF, or CA ROSCOE.

. The advantages of using the cross-memory drivers are:

  . Users are authorized by cross-memory drivers.
    When you use the cross-memory services drivers for the ISPF, TSO, or ROSCOE interfaces, users are authorized by
    cross-memory and do not also need authorization from the online interface (for example, TSO).

 . Multiple versions of View/Deliver can run simultaneously.
   When you use the cross-memory services drivers for the ISPF, TSO, or ROSCOE interfaces, you can run multiple 
   versions of View/Deliver concurrently.  This ability supports migration and makes it easier to migrate when you
   are converting to a new version level of View/Deliver.

 . User logons can roll to the next available task.
    As you are able to define a set number of users for a particular task, when the number of maximum users has been
    reached for that task, other users that subsequently log on are rolled to the next available task.

Points to know if a XMS task is used:

 . If there are multiple releases of View/Deliver being run, a XMS task is needed for each release.
    As only one release can have its load library in the linklist, a //STEPLIB statement is needed to point to the other    
    release's load library where necessary.