Because the data set is new in an initial allocation, the data class ACS routine is invoked to determine the characteristics of the data set. The storage class ACS routine is then invoked to determine whether the data set is system-managed.

The management class ACS and storage group ACS routines are invoked only if the data set is system-managed and a storage class was assigned.

Each time a dynamic allocation is issued by application programs, such as DFSMShsm RECALL, SMS follows this initial allocation path (except for the data class ACS routine which is not invoked).