Method of controlling flash memory
AssigneeOki Electric Industry Co., Ltd.
InventorHirofumi Muramatsu
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Abstract
In order to control efficiently a flash memory in the case where small-scale data are frequently rewritten, a method of controlling a flash memory in which a data storage region is divided into unit sectors and data can be erased by every sector as a unit, is configured that the sector comprises a sector control region and a plurality of pages, and included are both available/unavailable flag information about the page concerned and an occupied/unoccupied map showing a data storage location of the data storage region on the page concerned. By employing such a configuration, it is easy to decide whether the page referred to is available or unavailable and the configuration is suitable for frequently renewing and adding pages, which are of a large quantity and on a small scale.
Claims12
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=2nbytes, where n is an integer.
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, and
- the page control region of each of said plurality of pages further includes a page extension flag, representing whether the page concerned is dependent on a preceding page or not.
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, and each of said plurality of pages comprises a page data region having a record size that is variable in length, and a page control region that includes a piece of available/unavailable flag information about the page concerned, a page extension flag representing whether the page concerned is dependent on a preceding page or not, and record size information about the page data region of the page concerned.
A method for organizing a flash memory having a data storage region, comprising:
- dividing the data storage region into a plurality of sectors;
- dividing each sector into a sector control region and a plurality of pages;
- and
- dividing each page into a page control region and a page data region,
- wherein the page control region of each page includes a plurality of items of information about the page concerned, the plurality of items of information including an available/unavailable flag.
Dependencies are inferred from the claim text.