When a process waits for a block device data request to complete, it incurs I/O wait time, and all idle time becomes wait time.
当一个过程等待一个块设备数据请求完成时，它会增加 I/O 等待时间，而所有空闲都会变成等待时间。
2
In RCC dam construction project, sometimes because of the need for grouting and river diversion, the thin concrete block during long intermittence would be caused after a long idle time.