Patent ID: 6430653
Filing Date: 2002-08-06
Classification: G06F

Abstract:
A disk control unit connected to a computer and to a fixed drive, and comprising:an instruction decode circuit, a partition map, a predictive cache entry, a disk cache, a prefetch program, a prefetch decision circuit, and a disk control circuit, wherein: said instruction decode circuit is connected to said computer to decode instruction from said computer, said partition map is connected to said instruction decode circuit to maintain a partition information of said fixed drive, said predictive cache entry is connected to said prefetch decision circuit to maintain a concatenation state of files which are contained in said fixed drive, said disk cache is connected to said instruction decode circuit to maintain both data which is read-in and written in said instruction decode circuit, and data which is read-in into said prefetch decision circuit, said prefetch program is connected to said prefetch decision circuit to include a decode program in every file of said prefetch decision circuit, said prefetch decision circuit is connected to said instruction decode circuit, to said predictive cache entry, and to said disk control circuit, and receives a read-in instruction from said instruction decode circuit, for determining which partition said read-in instruction belongs to by reference to the partition information of said partition map, then determining which file said read-in instruction belongs to by reference to said predictive cache entry, and subsequently determining which block that said read-in instruction is connected to and directing read-in of the determined block portion toward said disk control circuit and for storing prefetch data read-in previously in said disk cache, said disk control circuit is connected to said fixed drive, said instruction decode circuit, and said prefetch decision circuit, for receiving a read-in data and a write instruction from said instruction decode circuit and an instruction from said prefetch decision circuit, thus performing control of said fixed drive, and said instruction decode circuit transmits prefetch data which is stored in said disk cache toward said computer without performing a read operation on said fixed drive when the data regarding a read-in instruction coincides with said prefetch data stored in said disk cache, in the cases where said read-in instruction is sent from said computer.