Patent ID: 7184320

Claim:
A storage device employing a flash memory, wherein said flash memory is divided into a plurality of physical sectors identified by physical addresses, wherein said flash memory carries out data write operation of write data from a host system into a sector of said plurality of physical sectors in response to a host logical address accompanied with said write data from said host system, wherein said storage device includes a memory controller which generates a physical address in response to said host logical address for said data write operation of said write data from said host system, wherein said memory controller carries out address conversion from host logical addresses to physical addresses to generates said physical address in response to said host logical address, a method of operating the storage device, comprising: assigning one physical sector selected, by said address conversion, from said plurality of physical sectors to a specific host logical address in a preceding data write operation in which preceding data from said host system is to be written into said one physical sector identified by a preceding physical address converted from said specific host logical address by said memory controller; re-assigning another physical sector selected, by said address conversion, from said plurality of physical sectors to said same specific host logical address in a succeeding data write operation in which succeeding data from said host system is to be written into said other physical sector identified by a succeeding physical address converted from said same specific host logical address by said memory controller, said succeeding physical address being different from said preceding physical address, said succeeding data write operation being carried out in response to said same specific host logical address accompanied with said succeeding data from said host system after said preceding data write operation was carried out; erasing old data of said one physical sector, identified by said preceding physical address, in which unnecessary data is written; and storing a new correspondence between said succeeding physical address and said same specific host logical address within a table for said address conversion.