| 摘要 |
PURPOSE:To secure the secrecy in a protection area by enabling only a specified person who knows the method of memory access from a special form to perform a memory access according to said access method. CONSTITUTION:An electronic computer system contains a CPU1 and a main memory 2. the memory 2 includes a normal area 21a to which an access is possible with a normal memory access instruction, a protecting area 21b to which an access is possible with a special memory access instruction only, a segment table 31 and a page table 32. While the CPU1 includes a memory access part 11 which gives an access to the memory 2, an address register 12 which holds a logical address and a segment base register 13. Furthermore the part 11 contains a normal area access part 11a for access to a normal area 21 in the memory 2 and a protecting area access part 11b for access to a protecting area 11b.
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