Manner and the device which make the simultaneous operation of the shared memory system possible and make maximum

摘要

(57) Abstract This invention without degradating performance offers the price independently includes accessible, single shareable memory block as a graphic memory or as a main storage system memor computer system low. It confronts main system memor, to make desire satisfy, because it is difficult, (desire for display memory unlike) in order the unused part of the display memory to use as system memor, address memory it is possible by re-allocating to do. When the unused display memory re-is allocated, the necessity to designate the display memory as oversize is lightened, furthermore the memory size which can be procured easily is used and cost effectiveness is implemented. Furthermore, when graphic memory re-is allocated, although operation demand when it is worst is accepted the necessity to think of system memor and the display memory separately is evaded. According to the addition example, when the expanded memory is included, it can raise the simultaneity between the multiple memory banks, it can make operational efficiency improve with that. Mapping the addressable point position of the expanded memory on the bottom of the active system address space, it is possible to make the addressable point position of tip resident in based system memor move with respect to the expanded memory space. Because of this, the operating system uses memory first from the expanded memory, when the expanded memory is allocated completely, reaches the point where based system memor is used only.