Patent ID: 6098191
Filing Date: 2000-08-01
Classification: G06F

Abstract:
A storage unit subsystem connectable to a processing unit, comprising:a plurality of storage units;a control unit for controlling said storage units;wherein each data group is formed by m (m.gtoreq.1) ordinary data and n (n.gtoreq.1) redundant data for recovering said ordinary data, the ordinary data and the redundant data in each data group are stored on record media of different storage units, respectively, as records, each record being capable of assuming a state to store said ordinary data or said redundant data and a state not to store any of said ordinary data or said redundant data, and said plurality of storage units include a plurality of records belonging to a plurality of said data groups;wherein said control unit receives a write request with write data from said processing unit, reads old data corresponding to said write data from said storage unit, issues a request with said old data and said write data that orders to generate redundant data corresponding to said write data to said storage unit that said redundant data is stored; andwherein said storage unit receives said request from said control unit, said old data, and said write data, reads the information for generating said redundant data from a record, generates said redundant data from said old data, said write data and the information read from the record, and writes redundant data to a record not to be stored any of said ordinary data or said redundant data.