The following is from the CA Librarian User Guide, Chapter 6: Using LIB/AM (z/OS and OS/390):
A user-written program can dynamically allocate a LIB/AM file by issuing an SVC 99 and passing the subsystem name in the SVC 99 parameter block. Both simple dynamic allocation (by DSNAME only) and simple dynamic unallocation (by DDNAME only) are supported, and both sequential and partitioned access is permitted.
Note the following:
â– Dynamic concatenation of LIB/AM files is not supported.
â– The TSO ALLOCATE command does not currently support the SUBSYS parameter, therefore, LIB/AM cannot be used with the TSO ALLOCATE command. Use a UCR program, LAMALLOC, instead.