公开(公告)号：JPH05204762A

公开(公告)日：1993-08-13

申请号：JP10647392

申请日：1992-04-24

Applicant: IBM

Inventor： KAARU EDOWAADO KURAAKU ,  MAIKERU JIERAADO MOORU ,  KIYASUPAA ANSONII SUKARUJI ,  BASUKA SHINHA

IPC: G06F12/14 ,  G06F21/24

Abstract: PURPOSE: To make it possible to expand the level of protection of a protection key for memory storage which can be controlled by programming by adding a 3rd protection level. CONSTITUTION: An array 22 of protection keys contains three storage protection keys of an administrative class, an intermediate class, and a general class. A program routine which is operated with the access key of the administrative key can access all the storage blocks in the main storage 21. A program routine operating with the access key of the intermediate level can not access the storage blocks of the administrative level, but can access storage blocks to which the keys of the general and intermediate levels are assigned. With the program access key using a general storage key (PSK) of the 3rd level, only blocks having the same PSK value can be accessed.