System Installation Choices › Key z/OS Libraries › Linklist Duplicates Display

Linklist Duplicates Display

z/OS automatically recognizes some libraries as part of the linklist, such as SYS1.LINKLIB and SYS1.MIGLIB, according to standard z/OS convention. Other libraries must be explicitly designated as linklist libraries by their inclusion in the LNKLSTxx or PROGxx members in the logical parmlib.

Most data centers designate additional linklist libraries. Having multiple linklist libraries introduces the possibility of different versions of the same program in multiple libraries. Depending on the order in which the libraries are defined in the LNKLISTxx or PROGxx members, either the new version or the old version might be executed. This problem is compounded by the fact that large data centers frequently sort the library names alphabetically to make it easy to find them when editing the logical parmlib members. Thus, a library’s order search sequence might depend on its name rather than the timeliness of its contents.

The Duplicate Linklist Modules option identifies the linklist libraries that contain members that have the same names as those of members in other linklist libraries. These libraries can then be checked to make sure the current library is first in the search sequence.

To view the duplicate linklist modules

1. From the Primary Menu, select option 2.

   The System Installation Choices Menu is displayed.

2. Select option 4.

   The Key z/OS Libraries submenu is displayed.

3. Select option 5.

   The Duplicate Linklist Modules screen is displayed.

4. Enter S (Select) next to a library name.

   A list of programs in that library that are duplicated in other linklist libraries is displayed.

5. Enter B next to the library name to browse a library.
6. (Optional) Enter F to freeze and monitor changes to a library.