Abstract: UNLOAD and LOAD utility programs (24) in computer system memory (16) are used to transfer user and system data from one set of direct access storage devices (10, 12, 14) to the same or another set of direct access storage devices. The originating or sending system is off-loaded as a single complete entity by a system command to a sequential media (FIG. 3) following the Initial Program Loadable system load program. The system load program, when Initial Program Loaded on the receiving system, determines the new hardware configuration and alters the loaded system control information to reflect the new device types and device addresses and loads the system to the new DASD configuration and prepares it for normal processing on the new system.