Abstract: A nonvolatile storage device is provided with a nonvolatile main storage memory whose erase size is larger than a cluster size, and a buffer, i.e. a nonvolatile auxiliary storage memory. At the time of writing data in the memory, the data is temporarily stored in the buffer, then, a plurality of data in the buffer are collectively taken out to be stored in the main storage memory. Data in an original block is saved in a write block in the main storage memory. Thus, the data can be written in the main storage memory at a high speed.

Abstract: A nonvolatile storage device is provided with a nonvolatile main storage memory (114) whose erase size is larger than a cluster size, and a buffer (106), i.e. a nonvolatile auxiliary storage memory. At the time of writing data in the memory, the data is temporarily stored in the buffer (106), then, a plurality of data in the buffer (106) are collectively taken out to be stored in the main storage memory (114). Data in an original block is saved in a write block in the main storage memory. Thus, the data can be written in the main storage memory (114) at a high speed.

Abstract: A nonvolatile storage device according to the invention is a nonvolatile storage device into which data is inputted from an external device on a sector unit, and includes: a main memory which is nonvolatile and in which data is written on a page unit, the page unit being larger than the sector unit; an auxiliary memory which holds at least a single page worth of the input data; a memory judging unit that judges whether or not data held in the auxiliary memory is equal to or larger than data of the page unit; and a memory control unit that writes, in a new page of the main memory on the page unit, the data held in the auxiliary memory when the memory judgment unit judges that the data held in the auxiliary memory is equal to or larger than data of the page unit.