Patent ID: 7293144
Filing Date: 2007-11-06
Classification: G06F

Abstract:
1. A method for controlling a cache memory of a storage device by a cache controller, the storage device being connected to a plurality of host computers, and the cache memory including a plurality of cache slots for temporarily holding data of the storage device to be accessed by the host computers, comprising the steps of: (a) recognizing a priority to each of the host computers; (b) recognizing a minimum number of cache slots to each of the host computers; (c) receiving an access request for data of the storage device from an access requesting host computer; and (d) allocating to the access requesting host computer a cache slot for holding the data thus requested so that allocated cache slots form a queue on a host computer basis, the cache slots in the queue being linked in an order of allocation, wherein, as a cache slot for holding the requested data, a least-recently allocated cache slot of the queue for a lower-priority host computer is reallocated to a most-recently allocated cache slot of the queue for the access requesting host computer, if there exists no free cache slot in the cache memory, and the requested data does not exist in the cache memory, and the priority of the access requesting host computer is higher than that of the lower-priority host computer, and a number of cache slots of the queue for the lower-priority host computer exceeds the minimum number for the lower-priority host computer.