CACHE REPLACEMENT SYSTEM

PROBLEM TO BE SOLVED: To perform the I/O cache control in consideration of the data transfer characteristic of an I/O device and to effectively use an I/O cache by setting the priority of cache replacement according to the characteristic of the device which is connected to an I/O controller. SOLUTION: An address comparison part 8 compares the address which is held at a transaction receiving part 6 with the address of the address field of an I/O cache 7 and sends the result of this comparison to a replacement control part 10. An agent attribute table 9 consists of an agent # field and an agent attribute field. roe agent # field stores the I/O agent number which is set by software, and the agent attribute field stores the attribute that is used when the block cached in the cache 7 is replaced and decides the priority of cache replacement.