Patent ID: 6430650
Filing Date: 2002-08-06
Classification: G06F

Abstract:
A semiconductor storage device comprising:a flash memory comprising a plurality of erase blocks, each of the plurality of erase blocks comprising a plurality physical groups, each of the plurality of physical groups comprising n physical sectors, wherein n is a natural number; a random access memory storing a conversion table for converting a logical group number to a physical group number; and an access controller which receives a logical sector number being a number used to specify a logical sector to be accessed by an operating system, converts the logical sector number to a logical group number and an offset by dividing the logical sector number with the number n and sets a quotient of the division to the logical group number and a remainder of the division to the offset, determines a physical group number corresponding to the logical group number with reference to the conversion table in said random access memory, and accesses in said flash memory a physical sector of a physical sector number determined as a sum of the offset and a product of the physical group number and the natural number n; wherein said flash memory further comprises a storage area for storing group management data provided for each of the plurality of physical groups in each of the plurality of erase blocks, the group management data for a first physical group comprising link data which links the first physical group to a second physical group when data in one or more physical sectors in the first physical group have been updated from the counterpart in the second physical group; and said access controller determines a physical group number corresponding to the logical group number with reference to the link data in the group management data for a physical sector which stores data not updated when the data in the first physical group have been updated from the counterpart in the second physical group.