Abstract: Atomic data are stored in blocks on a hard disk. The blocks are grouped into a committed block aggregate P1, which exists only on the hard disk, a next-generation committed block aggregate C1, which is converted into a committed block aggregate at predetermined times, and an atomic block aggregate S3, which is created for every user based on the committed block aggregate C1. User A makes desired data changes to S3. When user A terminates the data processing, the block aggregate storing the data is merged, like from the atomic block aggregate S4 to committed block aggregate C2, and stored on the hard disk as a committed block aggregate P3.

Abstract: Atomic data are stored in blocks on a hard disk. The blocks are grouped into a committed block aggregate P1, which exists only on the hard disk, a next-generation committed block aggregate C1, which is converted into a committed block aggregate at predetermined times, and an atomic block aggregate S3, which is created for every user based on the committed block aggregate C1. User A makes desired data changes to S3. When user A terminates the data processing, the block aggregate storing the data is merged, like from the atomic block aggregate S4 to committed block aggregate C2, and stored on the hard disk as a committed block aggregate P3.

Abstract: Most drivers of flash memories used for embedded systems are often designed to use power from batteries, but not from a commercial power supply, and therefore are required to be protected against power failures. In addition, if a power failure occurs in the middle of programming a cell, the driver of an MLC flash memory may corrupt not only data in a page subjected to the program operation but also data already stored in the other pages in the same cell, which is an unrecoverable problem. According to the present invention, in order to write data into a block, the driver of the MLC flash memory has steps for preparing another block and writing identical data into corresponding pages of the two blocks alternately and makes it possible to write the data without data loss even if a power discontinuity or power failure occurs.