To properly perform its processing, SMP/E must maintain a great deal of information about the structure, content, and modification status of the software it manages. Think of all the information SMP/E has to maintain as if it were all the information contained in the public library.

In a public library, you see bookshelves filled with books and a card catalog with drawers containing a card for each book in the library. These cards contain information, such as the title, author, publishing dates, type of book, and a pointer to the actual book on the shelf.

In the SMP/E environment, there are two distinct types of "bookshelves." They are referred to as the distribution libraries and the target libraries. In much the same way the bookshelves in the public library hold the library books, the distribution and target libraries hold the elements of the system.

Distribution libraries contain all the elements, such as modules and macros, that are used as input for running your system. One very important use of the distribution libraries is for backup. Should a serious error occur with an element on the production system, the element can be replaced by a stable level found in the distribution libraries.

Target libraries contain the executable code needed to run your system (for example, the libraries from which you run your production system or your test system).

As you think of the analogy of the public library, you can see that there is one important piece of that picture that we have not yet considered. In the public library, there is a card catalog to help you find the book or piece of information you are looking for. SMP/E provides the same type of tracking mechanism in the form of the consolidated software inventory (CSI).

The CSI data sets contain all the information SMP/E needs to track the distribution and target libraries. As the card catalog contains a card for each book in the library, the CSI contains an entry for each element in its libraries. The CSI entries contain the element name, type, history, how the element was introduced into the system, and a pointer to the element in the distribution and target libraries. The CSI does not contain the element itself, but rather a description of the element it represents.

The cards in the public library card catalog are arranged alphabetically by the author's last name, and by the topic and title of the book. In the CSI, entries for the elements in the distribution and target libraries are grouped according to their installation status. That is, entries representing elements found in the distribution libraries are contained in the distribution zone. Entries representing elements found in the target libraries are contained in the target zone. Both of these zones serve the same purpose as the drawers of the public library card catalog.

In addition to the distribution and target zones, the SMP/E CSI also contains a global zone. Figure 1 shows the relationship between SMPE zones and libraries.

Figure 1. Relationship between SMP/E zones and libraries

The global zone contains:

• Entries needed to identify and describe each target and distribution zone to SMP/E
• Information about SMP/E processing options
• Status information for all system modifications (known as SYSMODs) that SMP/E has begun to process
• Exception data for SYSMODs requiring special handling or that are in error.

In SMP/E, the term exception data usually refers to HOLDDATA. HOLDDATA is often supplied for a product to indicate a specified SYSMOD should be held from installation. Reasons for holding a SYSMOD can be:

• A PTF is in error and should not be installed until the error is corrected (ERROR HOLD).
• Certain system actions may be required before SYSMOD installation (SYSTEM HOLD).
• The user may want to perform some actions before installing the SYSMOD (USER HOLD).

All the information located in the global zone, combined with the information found in the target and distribution zones, make up the data that SMP/E requires to install and track the system's software, which is often a great deal of data. You can display this information using the following SMP/E facilities:

• Query dialogs: The easiest and fastest way to obtain just the information you want
• LIST command: When you need an all-inclusive hardcopy listing of information about your system
• REPORT commands: To check and compare the zone contents and generate command output that can be used to update your system
• SMP/E CSI application programming interface: To write an application program to query the contents of your system's CSI data sets.