PURPOSE: To delete operation and to resume the deleted operation continuously with respect to plural continuous operations by using a controlled update log.

CONSTITUTION: If the deletion of operation is executed, updating is reversed by reading it until an update log record attains at next operation pause record at the position of a current log address CLA. When a previous operation pause record is attained, the current log address is set to the pause record. Tracing back the update log records 3-1 and 3-2, the current log address CLA points the backward position of the previous operation pause record. The deletion of operations is possible even by going back to an initial operation.