| 摘要 |
PURPOSE:To make it unnecessary for software to recognize the duplication of a file by operating an in-operation system memory part, a standby system memory part and a semiconductor memory device provided with a control part according to a specific instruction from a central processing unit. CONSTITUTION:The semiconductor memory device is provided with the in- operation system memory part 300, the standby system memory part 400 and the control part 200. According to the indication from the central processing unit the in-operation system memory part 300 and the standby system memory part 300 are simultaneously selected, and are caused to execute the same action. When the in-operation memory part 300 develops a trouble, the contents in the register 410 of the standby memory part 400 are rewritten in the in-operation system, and simultaneously the contents of the register 310 of the in-operation system memory part 400 are rewritten in the standby system so as to separate the selection of the in-operation system. Moreover the occurrence of the replacement of the ion-operation and standby systems is reported to the central processing unit. Afterward the standby system memory part 300 is used in an in-operation system until the trouble of the in-operation system memory part 30 is removed.
|
