| 摘要 |
PROBLEM TO BE SOLVED: To secure the high secrecy for every memory system or memory chip just with addition of a simple circuit by using a means which decides an address where the overhead data are first detected among those block addresses by a secret algorithm within a page that is first read out of every block. SOLUTION: When a power supply is turned on, a memory system reads the head pages out of all blocks. At the same time, the head address of the data on the head page of every block is calculated by means of a secret algorithm A 4a. Then a block management table is produced from the head page data on the block. Furthermore, the original data are read out for calculating the head addresses of data on the following pages and stored (in an internal RAM of a CPU 3, for example). Then the commands of sector read, sector write, etc., are executed. In this command execution mode, the data head address of every page is calculated by means of the algorithm A 4a. |
