Preventing time out of an IO transaction during CPU re-initialization by controlling the IO transaction so that the time when the IO transaction is continuously stopped during the CPU re-initialization process is within a predetermined time that prevents complete time out of an interrupt of an IO transaction. In a case where the IO transaction would be continuously stopped for greater than the predetermined time during a CPU re-initialization the IO transaction is stopped and restarted within the predetermined time. The status of the interrupt during such stopping and starting is stored so as not to loose the interrupt status during the interval between such stopping and starting.