Abstract: The present invention relates to AG-AND-type flash memory which reads management information about a plurality of clusters in a short time, wherein a plurality of clusters are arranged as rows of a matrix, and a plurality of banks are arranged as columns. Single management information is stored in specific pages of all blocks belonging to a certain cluster. For instance, management information (having contents C0) about cluster is stored in specific pages of all blocks. Simultaneous access can be made to a plurality of the banks. Upon system startup, the management information is read obliquely such that the management information about cluster is read from bank 0; . . . , and such that the management information about cluster 3 is read from bank 3. Accordingly, the management information about a plurality of the clusters can be read in a single access operation.

Abstract: To provide an accessing device which allows reliable protection of important data. A memory accessing device has a file system device which manages a logical memory space and a driver device which maintains a correlation information between the logical memory space and a physical memory space and which physically accesses a flash memory based on the correlation information. The flash memory is physically divided into a plurality of strings. The file system device manages the memory space by dividing the memory space into a plurality of partitions each of which is set to one of RO and RW. The driver device specifies a permission type to write the data in a string by correlating each string to a single logical partition.

Abstract: An image file is managed more appropriately. When an image file is transferred from a camera to a server, a determination is made in advance as to whether or not an image file exists in both the camera and the server. When matching of image files is determined, an image file having the same file size is first identified. When an image file having the same size is present, partial hash values summarizing initial portions of the image files are then calculated. The partial hash values are compared with each other. When a match exists between the partial hash values, total hash values summarizing the entire image files are further calculated, and the total hash values are compared with each other. An image file having all of the same file size, the same partial hash value, and the same total hash value is determined to be an identical file.

Abstract: The present invention relates to AG-AND-type flash memory which reads management information about a plurality of clusters in a short time, wherein a plurality of clusters are arranged as rows of a matrix, and a plurality of banks are arranged as columns. Single management information is stored in specific pages of all blocks belonging to a certain cluster. For instance, management information (having contents C0) about cluster is stored in specific pages of all blocks. Simultaneous access can be made to a plurality of the banks. Upon system startup, the management information is read obliquely such that the management information about cluster is read from bank 0; . . . , and such that the management information about cluster 3 is read from bank 3. Accordingly, the management information about a plurality of the clusters can be read in a single access operation.

Abstract: To provide an accessing device which allows reliable protection of important data. A memory accessing device has a file system device which manages a logical memory space and a driver device which maintains a correlation information between the logical memory space and a physical memory space and which physically accesses a flash memory based on the correlation information. The flash memory is physically divided into a plurality of strings. The file system device manages the memory space by dividing the memory space into a plurality of partitions each of which is set to one of RO and RW. The driver device specifies a permission type to write the data in a string by correlating each string to a single logical partition.