Patent ID: 7032094

Claim:
A method of controlling a flash memory in which a data storage region of the flash memory is divided into unit sectors and the data storage region is erasable by sectors as units, wherein: each sector comprises a sector control region and a plurality of pages, each of said plurality of pages comprises a page control region that includes a piece of available/unavailable flag information about the page concerned and an occupied/unoccupied map representing data storage locations in the page concerned, said available/unavailable flag of each of said plurality of pages is composed of 1 bit, said occupied/unoccupied map of each of said plurality of pages is composed of m bits, and each of said plurality of pages further comprises a data region composed of 2m bytes, where m is a value selected in order to make (m+1) bits equal to 8 times an integer and in order to make 2m+(1+m)/8=2 n bytes, where n is an integer.