System Installation Choices › Parameter Library › Updating Parmlib

Updating Parmlib

Logical Parmlib data sets are typically partitioned data sets (PDS) that contain 80‑byte card‑image records. These are normally updated online through TSO or in batch using the IEBUPDTE utility. Many audit and security specialists recommend that no one should have standing update access to logical Parmlib data sets. In addition, because logical Parmlib data sets contains lists of authorized libraries, I/O appendages, SMF options, and other sensitive information, some experts recommend not even permitting read access.

Most logical Parmlib members are referred to only during IPL and in many cases, updates made after an IPL are not effective until the next IPL. Some operating system facilities can, however, be dynamically altered after an IPL has been performed. For example, the list of authorized libraries can be changed after an IPL.

To monitor changes to the logical parmlib, you can use the following displays:

• The APF Library Display (2.4.1) searches z/OS control blocks for its information instead of reporting the specifications in parmlib.
• The Parmlib Member Status Display (2.1.2) is valuable for monitoring changes to these key system libraries because the display can detect changes made to logical Parmlib members.