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File Freezer

Every data center contains files that are vital to the operation of your company, such as payroll files, production files, and control files. Usually, such files are changed infrequently. However, when these files are changed, they can have a tremendous effect on your data center and your company. It is important to monitor changes to such sensitive files and ensure that change control practices are followed. You can use the File Freezer options to take “snapshots” of files to review any changes made to them. You can use these options to freeze key z/OS system files, such as SYS1.PROCLIB or the JES2 parameter library. In the same way, you can compare snapshots of production master files to ensure that their integrity was not compromised.

The CA Auditor freezer exists in two different places in the panel hierarchy: as the Program Freezer (5.5) and as the File Freezer (6.6). The initial change panel (before history or log line commands are entered) differs slightly (the Program Freezer display is more member‑oriented). The two freezers perform the same function for two different entities: programs and files. To CA Auditor, a program is anything that has a member name or an area of storage (such as SVCs and subsystems). A file is any data set or member.

The File Freezer can run against members of a PDS (source lib, loadlib, parmlib, and so on), PDS/E, or CA Panvalet or CA Librarian library. It can also run against a VSAM KSDS or ESDS data set, a sequential data set, or CA Endevor elements. The File Freezer does not work against areas (such as SVCs or subsystems).

You can also use the File Freezer to perform a library freeze, which freezes and saves other information from the PDS directory. The library freeze reports whether there are changes at the member level, but does not do any input or output to the members. Therefore, it is usually faster than freezing all of the members individually, while providing most of the same information. The limitation of a library freeze is that it cannot detect changes if a member changed without the directory changing. This is rare, but can occur with the AMASPZAP program. This is possible with low‑level EXCP I/O where the programmer writes his own Channel Command Words (CCWs). To do a library freeze, specify the PDS/PDSE data set name but do not specify a member name or mask.

When CA Auditor freezes a file, it creates a unique “digital signature” for the file and stores that signature with other information about the file in the CA Auditor freezer database. CA Auditor then compares this signature to the signature it creates the next time you ask CA Auditor to freeze the file. If CA Auditor finds changes to a file, the entry is flagged on the display. Each frozen file requires 160 bytes of storage in the freezer database, which is located in DBASE1. You can freeze as many files as DBASE1 can hold.

CA Auditor displays the results of its freezes to a file in two formats: a change history and a change log. The file’s change history shows the results of up to 10 freezes to the file. These results are displayed in terms of time periods by comparing the most recent freeze to each previous freeze. The change history lets you quickly discover whether the file was changed and changed back again. It also lets you monitor your staff by showing whether they are freezing the file regularly.

The file’s change log displays up to 10 changes to the file. The change log displays only those intervals during which a change occurred. CA Auditor discards any intervals when the file remained unchanged. Therefore, the change log shows you the “end points” of relevant time intervals. The information on the change log can help you determine how thorough your data center’s testing program is, because it shows you how often a file is being changed.

When CA Auditor performs a freeze on a file, it saves this information in a work group in the freezer database. Work groups are pools or “folders” that store freezer processing. By default, CA Auditor provides you with a personal work group to process your freezer requests. No other user can access your personal work group. However, if you want to share the results of freezer processing with other users, you can select a different work group or create a new one. You can create a new work group by selecting option 1.4 from the Change User Profile Information menu. See the Select Work Group section in the “User Profile Information” chapter for a description of how to select and create a work group.

If you want CA Auditor to ask you to select a work group every time you want to freeze a file, then you must enable prompt mode. By default, CA Auditor does not prompt you for a work group. For an explanation of how to enable or disable prompt mode, see the Work Group Prompt Mode section in the “User Profile Information” chapter.