CICS, IMS and JCL Resources

The resources that your CICS application uses need to be defined, so that you have a CICS environment in which you can run and debug your applications. The resource definitions are set up as part of the migration of your application from the mainframe. They are stored in a Resource Definition file called dfhdrdat.

IMS and JCL applications also use CICS-style resource definitions, defined in the dfhdrdat file.

The resource definitions include:

• A system initialization table (SIT)

  The SIT defines the initialization parameters to use when the enterprise server that runs your application is started. You might need to change some of these parameters for your project.

  A SIT is required for CICS, IMS and JCL applications.

• A startup list

  The startup list contains the list of the groups of resources to be used. Enterprise Server loads all the groups in the startup list. The base startup list dfhlist contains recommended system groups that you should include in all your user-defined startup lists.

  A startup list is required for CICS, IMS and JCL applications.

• Resource groups

  Resource groups are sets of resource definitions that define the programs and files that are used by the enterprise server running your application. If you create any resource groups you need to add them to the startup list, or you can add them at execution time in Enterprise Server with the CINS supplied transaction.

  Resource groups for CICS include:

  • Program Control Table (PCT) - this defines the transactions that your application uses
  • File Control Table (FCT) - this defines information about the files that your application uses, such as the file type (KSDS, ESDS, RRDS) and minimum and maximum record length
  • Processing Program Table (PPT) - this defines the programs that are invoked by transactions or other programs.

  The only resource group you need for JCL is a JES resource group. This contains definitions of special service execution processes which start when the enterprise server is started, and which run JCL jobs and handle the sending of job output to a printer.

  IMS applications also need to use the JES resource group, as it contains definitions of the message processing regions (MPRs) which start when the enterprise server is started.