PURPOSE: To resolve overhead, by making the address conversion table, which is used to cause physical addresses on the main storage to coincide with addresses on the actual storage, into hardware partially.

CONSTITUTION: Bit 0 of control register CR7 indicates whether the physical address of the main storage coincides with the address of the actual storage or not, and this bit 0 is "1" if they coincide with each other. In case of loading of address conversion table information, hardware for the aid of the virtual computer checks bit 0 of control register CR7 and sets address data on the main storage designated by the operand of the load control instruction of instruction register 1 to the control register if bit 0 of control register CR7 is "1". When the physical address on the main storage coincides with the address on the acutal storage, loading of address information is dependent upon hardware for the aid.