z/OS: XMS Access Method

System Configuration for the XMS Access Method

Installation Tasks

Install the SASVXMS load module. See Steps for Installing the Load Module.

Note: The version of SASVXMS that is distributed with each maintenance release of SAS/SHARE can be used only with that maintenance release.
Define an anchor point. See Defining an Anchor Point.

Steps for Installing the Load Module

To install the SASVXMS0 load module, perform these tasks:

Copy SASVXMS0 into an authorized link list library.
- You can copy the module SASVXMS0 into any authorized library that is part of the link list.
- Alternatively, you can install this module into the link pack area.
  
  You can use any standard utility program to copy the module SASVXMS0 from your HLQ.LIBRARY data set to your link list library.
Rename SASVXMS0.

After you copy SASVXMS0 into the appropriate library, you must rename it. You can use any standard utility to rename the module.
- If you have a previous release of SAS/SHARE installed, rename SASVXMS0 to SASVXMSn, where n is the last digit of the release of SAS. Specify the communications access method as XMSn.
  
  For example, for Release 6.08, rename SASVXMS0 to SASVXMS8 and specify the access method as XMS8. For details, see Specifying XMS as the Communications Access Method.
- If you do not have a previous release of SAS/SHARE installed, rename SASVXMS0 to SASVXMS. Specify the communications access method as XMS in the SAS configuration file for batch processing and in the TSO CLIST. For details, see Specifying XMS as the Communications Access Method.
When SAS/SHARE loads the module SASVXMS, it must find that module marked as authorized, re-entrant, and reusable and that it was loaded from an authorized library.

Defining an Anchor Point

Anchor Point: Definition

The anchor point is a place in common memory that can be located by servers and clients and that is used to store and retrieve cross-memory communication information.

The anchor point is specified by defining an inactive z/OS subsystem. Doing this causes z/OS to create a subsystem communications vector table (SSCVT) at IPL time. The SSCVT chain is in common memory and easily accessible to the cross-memory access method routines. The SSCTSUSE field of the SSCVT is available to these routines and is used as the anchor point for their control blocks.

Steps for Defining an Anchor Point

Note: If you have defined an anchor point for a previous release of SAS/SHARE, do not repeat these steps now. [cautionend]

To define an anchor point, perform these tasks:

Define an inactive z/OS subsystem by adding the entry SAS0 to any of the following:
- the SCHEDULER SYSGEN macro instruction
- the IEFJSSNT member of 'SYS1.LINKLIB'
- an IEFSSNxx member of 'SYS1.PARMLIB'
CAUTION:
Do not use the name SAS0
if it conflicts with standards or conventions at your site. Regardless of the method that is used, you must include the subsystem name, but you should not specify an initialization routine name.

For details about each option, see the z/OS system initialization and tuning documentation.

Although you define a subsystem to z/OS, the subsystem will never be considered active and will provide no system services, because the SSCTSSVT field of the SSCVT will never be non-zero.
Assign the anchor point to the SUBSYSID system option.

For details, see SAS/SHARE SUBSYSID= Option.

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