Components of an IMSplex

The following sections discuss the components of an IMSplex:

• "Common Queue Server"

• "Common Service Layer"

Common Queue Server

Common Queue Server (CQS) is a generalized server delivered with IMS that manages data objects on a coupling facility list structure, such as a queue structure or a resource structure, on behalf of multiple clients. CQS receives, maintains, and distributes data objects from shared queues on behalf of multiple clients. Each client has its own CQS access the data objects on the coupling facility list structure. IMS is one example of a CQS client that uses CQS to manage both its shared queues and shared resources.

Related Reading: For more information about CQS, see "Common Queue Server Address Space" on page 40.

Common Service Layer

The CSL provides the infrastructure for improving IMS systems management. The CSL is made up of three IMS address spaces:

• The Operations Manager (OM)

• The Resource Manager (RM)

• The Structured Call Interface (SCI)

The CSL components and IMS subsystems in an IMSplex can be called IMSplex components.

Related Reading: For complete information about CSLs, see IMS Version 9: Common Service Layer Guide and Reference.

Figure 28-1 on page 497 illustrates a sample IMSplex configuration that includes the CSL, a single point of control (SPOC), and automated procedures:

Figure 28-1. Sample IMSplex Configuration with a CSL

• The operating system image includes address spaces for OM, SCI, RM, an IMS control region, and IMS CQS.

• The operating system image shares a coupling facility and databases.

• A SPOC application, an automation application, a master terminal, and an end-user terminal all access the z/OS image.

Operations Manager

The Operations Manager (OM) controls the operations of an IMSplex. OM provides an application programming interface (the OM API) through which commands can be issued and responses received. With a single point of control (SPOC) interface, you can submit commands to OM. The SPOC interfaces include the TSO SPOC, the REXX SPOC API, and the IMS Control Center. You can also write your own application to submit commands.

Specifically, OM can:

• Route IMS commands to IMSplex members registered for the command.

• Consolidate command responses from individual IMSplex members into a single response and provide that response to the originator of the command.

• Provide an API for automated operator commands.

• Provide a general user interface to register commands to support any command-processing client.

• Provide user exits for command and response edit and command security.

One OM must be defined in the IMSplex to use OM functions. Each z/OS image can have more than one OM. If multiple OMs are defined in the IMSplex, any OM defined can perform work from any z/OS image in the IMSplex.

Resource Manager

The Resource Manager (RM) is the component of the CSL that manages global resources and coordinates IMSplex-wide processes on behalf of its clients. IMS is an example of one such client. IMS uses RM to:

• Manage the following resources: transactions, LTERMs, MSNAMEs, nodes, users, user IDs, and APPC descriptor names.

• Ensure that a resource that is defined as a transaction, LTERM, or MSNAME is defined as the same resource type for all the IMSs in the IMSplex.

• Coordinate IMSplex-wide processes, such as performing global online changes.

RM uses the Common Queue Server (CQS) to maintain global resource information in a resource structure. A resource structure is a coupling facility list structure that all CQSs in the IMSplex can access.

Structured Call Interface

The Structured Call Interface (SCI) is the component of the CSL that provides the communication between IMSplex components, whether they are on one z/OS image or multiple z/OS images.