Documenting the system characteristics

You must create an independent body of information that documents the design and operation of the production system. This material is derived from the application requirements and includes the intended use of IMS facilities.

The following list describes the main documentation activities.

• Documenting the IMS system definition

  The detail of your design for an IMS online system is reflected in the system definition macro specifications. The input to the first stage of system definition processing can be used as a major documentation tool. Including comments on the choice of parameters should help you control definition changes.

  The IMSCTRL macro statement offers an ETO option that creates a report of current ETO descriptors in the network. You can use the ETO descriptor report to monitor your current network definition.

  Related reading: For more information about commenting on parameters and information about the IMSCTRL macro, see IMS Version 15.2 System Definition.

• Documenting the IMS network in DB/DC and DCCTL environments

  Within the broader scope of system documentation, you need to document the details of the IMS network. Start this documentation as soon as initial plans for an application system become available. The advantage to starting early is that you can become familiar with the physical network and the way it will logically be used by IMS connections. When your online IMS system uses terminals that are part of a network defined to VTAM®, you might be able to use some of the documentation developed by the system programming staff.

  Documenting in detail allows you to:

  • Familiarize yourself with the features and operation of the terminal devices
  • Find out if the application is going to use the terminal in an unusual way and, if so, research the potential problems
  • Prepare for IMS system definition stage 1 input
  • Prepare ETO descriptors
  • Prepare LU 6.2 descriptors
  • Plan for the installation and network generations
  • Understand the operational aspects of subsets of the total configuration
• Documenting terminal profiles in DB/DC and DCCTL environments

  One way to document the required network, after the major design is stable, is to record the intended use and characteristics of each terminal. You construct a profile that contains:

  • The terminal type, its required features, and the type of connection it is to use
  • What options were chosen for the device and the reason for the choice
  • The characteristics of how the terminal is to be used by the application
  • The proposed LTERM names that can be associated with the terminal or the user
  • If a VTAM-supported device, the node name and transmission characteristics
  • The extent of the proposed usage and whether the device is to be shared with non-IMS users
  • The diagnostic procedures that are appropriate for the device
  • User profiles and user profile security

  For dynamic terminals, you should maintain a record of the characteristics of dynamic terminals and users to make future changes easier.

• Documenting transaction profile names for APPC/IMS

  Definitions of transaction program names (TPNs) are contained in the APPC/MVS resource, TP_Profile. Within TP_Profile, TP profile data sets provide attribute information for each TPN. You can define TPNs that have different characteristics for each LU name with which they are associated.

  Related reading: For more information on TP names, see IMS Version 15.2 Communications and Connections.

• Documenting the configuration of the production system

  You should create a configuration map showing how individual terminals and clusters of terminals are to be connected in the network. This gives you some insight as to how to specify the network control to the MTO. Having the configuration map is also an aid when you interact with various technical specialists. The map should show:

  • Processors or host computers
  • Channels and lines (including the type of line)
  • Communication controllers
  • Control units and the terminal attachments
  • VTAM node names
  • For XRF systems, USERVAR or MNPS ACB name
  • Alternative connections or configurations

  To solve problems that might arise, you must be able to identify the terminal or control unit that has the problem. You can assist both end users and service personnel by placing identifying labels on the devices. In addition to the IMS address or node name and the LTERMs appropriate for that terminal, include the hardware address, circuit identification, and other data that might be necessary.