Chapter 15: Configuring MTO-enabled Enterprise Servers for IMS

This chapter describes how to create and configure IMS-enabled enterprise servers.

Overview

If you want to run IMS applications in an enterprise server, you can either create a new enterprise server specifically for this purpose, or use an existing enterprise server. If you create a new enterprise server, you should choose Micro Focus Enterprise Server with Mainframe Transaction Option on the first page of the Add Server dialog. Information on how to do this is contained in the section Enabling IMS for an Enterprise Server.

Once you have created a new enterprise server or modified an existing one, you can configure it for IMS. Depending on your IMS applications, the various configuration operations you need to perform are as follows:

These operations are covered in the following sections.

Resources, SITs and startup lists are all CICS concepts. This is because support for IMS in Enterprise Server is closely integrated with support for CICS. As a result, much of the configuration necessary to run CICS applications in an enterprise server is also necessary to run IMS applications. For further information about the link between IMS support and CICS support, including a brief introduction to CICS concepts, see the section MTO and CICS Support.

Some of the steps covered in this chapter require you to use Enterprise Server Administration. For an introduction to this tool see the chapter Introduction to Enterprise Server Administration in your Enterprise Server Configuration and Administration Guide.

MTO and CICS Support

This section provides a brief overview of the CICS concepts with which you need to be familiar in order to configure enterprise server for use with IMS. This is necessary because support for IMS in Enterprise Server is integrated with support for CICS. If you are familiar with basic CICS concepts you can skip this section.

In CICS, items of software or hardware for use by applications are called resources. Mainframe Transaction Option adds to Enterprise Server facilities for defining, controlling and monitoring resources. These facilities have been extended to include resources needed by IMS applications. You don't need CICS experience to use these, but you do need a basic understanding of the structure, so for readers unfamiliar with the CICS model, here is a quick overview.

In CICS, you define sets of resources. These sets of resources are called resource groups.

A CICS region is an environment for running CICS applications. When you create a region, you specify a system initialization table (SIT), which gives details of how the region is to be configured. One item specified by the SIT is called a startup list; this is a list of resource groups that are to become available automatically when the region is started.

In Enterprise Server for Windows or UNIX, an enterprise server is equivalent to a CICS region. To run IMS applications, you need to define special service execution processes (SEPs) called message processing regions (MPRs). You define these MPRs as CICS-style resources. Resources always belong to resource groups, so you also need to define a resource group, which needs to be referenced by a startup list, which needs to be referenced by a system initialization table (SIT). You then need to specify that the enterprise server is to use this SIT.

Figure 15-1 shows the hierarchical structure of SITs, startup lists, resource groups, and individual resources. The bottom line of the figure shows some more types of CICS resources - a program control table (PCT), file control table (FCT) and program processing table (PPT).

Structure of CICS Resources

Figure 15-1: Structure of CICS Resources

For more information about CICS Support within MTO, see Part 2 of this book. For more information about Enterprise Server, see your Enterprise Server Configuration and Administration Guide.

Adding IMS-specific Resource Definitions

IMS support includes two new transactions, /CIC and /IMS, that you use to switch enterprise servers to CICS and IMS modes respectively. In order for these new transactions to be available you need to update your resource definition file using the caspcupg command.

To update your resource definition file, enter the following command:

caspcupg /dp=resourcedefinitionpath /o

where resourcedefinitionpath is the path to the system resource defintion file to be updated. If you are using the default system resource defintion file ($COBDIR/etc/cas/dfhdrdat) you can omit /dp=resourcedefinitionpath. See caspcupg for more inforrmation on the caspcupg utility.

Updating a resource definition file with the /CIC and /IMS transactions in this way is a one-off process. Once you have used caspcupg to upgrade a resource definition file, any enterprise server that uses the updated resource definition file can use the new transactions.

Enabling MTO for an Enterprise Server

IMS support is part of Mainframe Transaction Option (MTO), so before you enable an enterprise server for IMS you must enable it for MTO.

How to

Note: When enabling an enterprise server for MTO you do not need to specify any settings for the CICS search paths unless your IMS application also includes CICS. If your application includes CICS see the chapters Configuring MTO-enabled Enterprise Servers for CICS and Administering MTO-enabled Enterprise Servers for CICS for more information.

Enabling IMS for an Enterprise Server

Once you have enabled MTO for an enterprise server you can enable IMS for it.

How to

Notes:

Specifying the Location of Genned Files

After you have enabled IMS for an enterprise server you need to specify the directory the enterprise server is to search for the IMS-related files it needs for your IMS applications.

How to

Specifying IMS Resources to a Resource Group

Before you can run an IMS application in an enterprise server you ensure that the following resources are included in a resource group:

You can add these resources to an existing resource group or create a new one for them.

How to

To update an enterprise server's resource groups you must first start the enterprise server then use Enterprise Server Monitor and Control (ESMAC). See the chapter Administering Servers Using ESMAC in your Enterprise Server Configuration and Administration Guide for more information on Enterprise Server Monitor and Control.

Adding a Transaction to a Resource Group

You add a transaction to a resource group by adding a PCT.

How to

Adding a Message Processing Region to a Resource Group

Every enterprise server that will be used to run IMS applications must have at least one message processing region. By adding a message processing region to a resource group you ensure that the message processing region starts each time the enterprise server starts.

How to

Adding a Resource Group to a Startup List

Having created a resource group for the resources needed by your IMS application, you need to add the resource group to a startup list.

How to

Enabling JCL for an Enterprise Server

If your IMS application includes any JCL you need to configure the enterprise server as described in the chapter Configuring MTO-enabled Enterprise Servers for JCL.

Defining Transactions

Usually, a transaction definition must exist for any program you want to run. There are two ways of creating transaction definitions:

These two methods are covered in the following sections.

Defining Transactions Manually

Before you can run any transaction you must define it.

How to

Importing Transactions

The transaction import facility enables you to extract IMS transactions from an IMS stage 1 file downloaded from the mainframe, and automatically add the transactions to your IMS project. Importing transactions is a process with two steps:

  1. The stage 1 file is read and all the transaction definitions are extracted into another file, known as a transaction file. Note that the stage 1 file never contains any transaction definitions for DLI programs as these are batch programs that run outside the IMS region.

    To create a transaction file from a stage 1 file enter the following command:

    mfims stage1ext stage1file transactionfile

    where:

    stage1fileis the stage 1 file downloaded from the mainframe.
    transactionfileis the transaction file to be created to contain the transaction and printer definitions needed to subsequently import into Enterprise Server. This is a flat text file, so you can edit it to remove any definitions that are not needed for the application to run under Enterprise Server.
  2. The transaction file from the first step is read and transaction definitions are added to the IMSGEN2.DAT file in the current directory.

    To import transaction defintions from a transaction file enter the following command from a Net Express command prompt:

    mfims stage1imp transactionfile [ADDREPL] [DELEXIST]

    where:

    transactionfileis the transaction file created by step 1.
    ADDREPLspecifies that you want to add new transactions and replace existing transactions. If you do not specify ADDREPL, new transactions are added but existing transactions are left unchanged.
    DELEXISTSspecifies that you want to delete all the existing transaction definitions in the IMSGEN2.DAT file before any are imported.

Calculating Shared Memory Area Requirements

The shared memory area calculation for an IMS-enabled enterprise server is essentially the same as for a Web services enterprise server, as described in the section Enterprise Servers in the chapter Configuration in your Enterprise Server Configuration and Administration Guide. Your calculation should also include 512 bytes for each 3270 client that will be concurrently connected to the enterprise server. Note that you must include your message processing regions in the total number of service execution processes.

If you are using CICS or JCL applications in the same enterprise server you will also need to perform the calculations described in Shared Memory Area in the chapter Configuring MTO-enabled Enterprise Servers for CICS and Shared Memory Area in the chapter Configuring MTO-enabled Enterprise Servers for JCL and add the relevant results to the figure you calculcated for IMS.


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