Falling back from using the IMSRSC repository

After using the IMSRSC repository to store resource and descriptor definitions, you can fall back either to using a resource definition data set (RDDS) or the MODBLKS data set instead for MODBLKS resources. For MSC resources, you can fall back to using the IMS.DFSCLL3x, IMS.DFSCLC0x, and IMS.DFSCLR0x data sets.