IMS fails to start when an MFS library contains a PDSMAN Space Map ($$$SPACE) member.
The PDSMAN Library Space Reuse facility offers a proactive solution to the problem of PDS out-of-space conditions and the related issues of unscheduled compressions, unnecessary compressions and PDS over-allocation. This facility dynamically reuses the dead PDS space whenever a member is updated. The space occupied by a deleted or replaced member is recorded and is made available for use by this or future updates. PDSMAN records space information in a special member (normally named $$$SPACE) called the Space Map that is created in the library.
IMS expects its MFS library members to have two bytes of binary zero user data in their directory entries. Since the PDSMAN Space Map member does not have user data written in this special format, IMS fails to start properly.
The problem is resolved by explicitly telling PDSMAN that the library is an IMS MFS library so that the proper directory entry user data can be set. This is done by specifying the LIBTYPE=IMSMFS parameter on the matching $UPDATE initialization control statement for library.
To specify LIBTYPE=IMSMFS:
Additional information is available in the following PDSMAN 7.7 documentation: