Abstract: In a data management method for supervising a non-volatile memory having a plurality of blocks erasable in a lump, each of the blocks being formed by a plurality of pages, each of the pages including a redundant area, the aggregate management information is used for data management to enable prompt booting. The distributed management information, as the management information for the respective blocks, is stored in the redundant area of each page, and the aggregate management information supervises data stored in each block, in a lump, in association with the distributed management information. It is verified, at the time of booting, whether the aggregate management information is effective. The data is supervised based on the aggregate management information when the aggregate management information is effective and, when the aggregate management information is not effective, the data is supervised based on the distributed management information.

Abstract: An external storage apparatus which incorporates a flash memory arranged to erase data in units of predetermined blocks and which is structured in such a manner that an error which is made when boot data is read is prevented. Boot data is stored in a plurality of different blocks. Moreover, an identification number indicating whether boot data stored in each of the blocks in which boot data has been stored is new or old is stored in each of the blocks. When the external storage apparatus is booted up, latest boot data among boot data stored in the plurality of the different blocks is read in accordance with the identification number. Latest boot data is used to boot the external storage apparatus up. When the external storage apparatus is booted up, whether boot data stored in the plurality of the different blocks is new or old is determined in accordance with the identification number. If old boot data exists, old boot data is rewritten to latest boot data.

Abstract: In a data management method for supervising a non-volatile memory having a plurality of blocks erasable in a lump, each of the blocks being formed by a plurality of pages, each of the pages including a redundant area, the aggregate management information is used for data management to enable prompt booting. The distributed management information, as the management information for the respective blocks, is stored in the redundant area of each page, and the aggregate management information supervises data stored in each block, in a lump, in association with the distributed management information. It is verified, at the time of booting, whether the aggregate management information is effective. The data is supervised based on the aggregate management information when the aggregate management information is effective and, when the aggregate management information is not effective, the data is supervised based on the distributed management information.

Abstract: An external storage apparatus which incorporates a flash memory arranged to erase data in units of predetermined blocks and which is structured in such a manner that an error which is made when boot data is read is prevented. Boot data is stored in a plurality of different blocks. Moreover, an identification number indicating whether boot data stored in each of the blocks in which boot data has been stored is new or old is stored in each of the blocks. When the external storage apparatus is booted up, latest boot data among boot data stored in the plurality of the different blocks is read in accordance with the identification number. Latest boot data is used to boot the external storage apparatus up. When the external storage apparatus is booted up, whether boot data stored in the plurality of the different blocks is new or old is determined in accordance with the identification number. If old boot data exists, old boot data is rewritten to latest boot data.

Abstract: An external storage apparatus which incorporates a flash memory arranged to erase data in units of predetermined blocks and which is structured in such a manner that an error which is made when boot data is read is prevented. Boot data is stored in a plurality of different blocks. Moreover, an identification number indicating whether boot data stored in each of the blocks in which boot data has been stored is new or old is stored in each of the blocks. When the external storage apparatus is booted up, latest boot data among boot data stored in the plurality of the different blocks is read in accordance with the identification number. Latest boot data is used to boot the external storage apparatus up. When the external storage apparatus is booted up, whether boot data stored in the plurality of the different blocks is new or old is determined in accordance with the identification number. If old boot data exists, old boot data is rewritten to latest boot data.

Abstract: In a tilt sensor including a sealed container which is comprised of a container body and a top cover plate which is adapted to close the container body and is provided on the inner surface thereof with a recess whose depth gradually increases from the peripheral edge toward the center thereof, and a holder which holds the sealed container, the top cover plate and the holder are provided with a positioning device which determines a relative angular position between the sealed container and the holder. A mask and a coat holder, which are used to form electrodes on the top cover plate are also disclosed.