| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To enable back up of data in a semiconductor memory device equipped with a flash memory. <P>SOLUTION: The semiconductor memory device includes an address conversion table for detecting physical addresses of at least two pages storing data written by designating a logical address from one of logical addresses to be designated by a reading request. The semiconductor memory device includes a page status register for detecting one page status allocated to each page, and page statuses to be detected include the at least following four statuses: (1) a latest data storage status, (2) a non latest data storage status, (3) an invalid data storage status, and (4) an unwritten status. By using the address conversion table and the page status register, at least two data (latest data and past data) can be read for one designated logical address from a host computer. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
