A data processing entity that includes a mass memory with a plurality of memory locations for storing memory blocks. Each of a plurality of software images includes a plurality of memory blocks with corresponding image addresses within the software image. The memory blocks of software images stored in boot locations of a current software image are relocated. The boot blocks of the current software image are stored into the corresponding boot locations. The data processing entity is booted from the boot blocks of the current software image in the corresponding boot locations, thereby loading the access function. Each request to access a selected memory block of the current software image is served by the access function, with the access function accessing the selected memory block in the associated memory location provided by the control structure.