PURPOSE: To provide a display control part emulation system whose performance can be prevented from lowering even for the application program(AP) of a target machine with different VRAM address constitution by providing the virtual graphic memory (virtual VRAM) area of the target machine on the memory of a base machine.

CONSTITUTION: The base machine is equipped with a memory managing mechanism which performs the mapping of a physical memory map on a logical memory map. The logical memory map compatible with the memory map of the target machine is provided on the memory 6 of the base machine by the memory managing mechanism, and an OS 14 and the AP 13 for target machine are stored in the memory map. Software to transfer data while performing the conversion of address constitution from a VRAM area on the logical memory map compatible with the target machine to that of the base machine is loaded on the base machine to efficiently convert the VRAM address of the target machine with different constitution.