| 摘要 |
PURPOSE:To prevent contention of access to the same data by each data processor by restarting other processor at the end of access of one processor to restart the access to a common storage device. CONSTITUTION:Plural data processors (processors) 11-13 and the common storage device 2 accessible in common from the processors 11-13 are provided. Ahead the access of the processor 11 to the device 2, the processor 11 issues a lock set instruction to read a lock flag of the device 2 and to set a read lock flag. When the processor 12 issues the lock set instruction after the processor starts accessing a data of the device 2, since the lock flag is already set, the accessing of the processor 12 to the device 2 is stopped. When the data access by the processor 11 to the device 2 is finished, the processor 11 issues a lock release instruction, the device 2 receives the lock release instruction to reset the set flag. Then the processor 12 restarts the access to the device in stop state by restarting the processor 12 in stopping state.
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