INTRA-PAGE PROTECTION SYSTEM

PURPOSE:To detect the writing defects when the writing actions are carried out to the areas in a page which are not allocated yet by a program by dividing a memory in the page into plural pieces and preparing a bit map corresponding to the division unit into a page table. CONSTITUTION:A memory conta...

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Bibliographic Details
Main Author TOMITA MASAHARU
Format Patent
LanguageEnglish
Published 14.03.1990
Subjects
CALCULATING
COMPUTING
COUNTING
ELECTRIC DIGITAL DATA PROCESSING
PHYSICS
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Summary:PURPOSE:To detect the writing defects when the writing actions are carried out to the areas in a page which are not allocated yet by a program by dividing a memory in the page into plural pieces and preparing a bit map corresponding to the division unit into a page table. CONSTITUTION:A memory contained in a page 2 is divided into plural pieces and the memory securing requests given from a program are allocated to these divided memories respectively. Then a bit map 1 corresponding to the division unit set into a page table. At allocation of memories, the corresponding bit is turned on the map 1. This bit is turned off at release of memories. At the same time, the ON/OFF state is decided for the bit corresponding to the relevant address on the map 1 when the memories are written and read. Thus an improper address is reported to the program when the bit is kept OFF. Then it is known whether the allocated areas are written or not when the memories are written by deciding the ON or OFF of the bit. In such a manner, the improper writing actions can be detected.
Bibliography:Application Number: JP19880226633