Patent ID: 7734893

Claim:
A virtual machine control program running on a computer system having a processing unit and a memory coupled to the processing unit, and for controlling execution of a plurality of operating systems each managing at least one virtual memory space based on information of a first address translation table stored in a first region of the memory that is allocated to a respective one of the operating systems, the virtual machine control program comprising: means for creating, in a second region of the memory that is dedicatedly used by the virtual machine control program, second address translation tables each defining address conversion information indicating correspondence between said at least one virtual memory space and a physical memory space of the memory on the basis of said first address translation tables; means for maintaining a correspondence table having information indicating correspondences between the first and second address translation tables; means for detecting an operation, by one of the operating systems, to switch address translation tables set in the processing unit from one of said first address translation tables to another of said first translation tables, and for searching through the correspondence table to obtain one of said second address translation tables corresponding to the another first address translation table; and means for setting the second address translation table corresponding to the another first address translation table to said processing unit so that the processing unit performs address translation in accordance with the second address translation table corresponding to the another first address translation table.