After the device file is successfully opened by calling open , this parameter could be acquired.
通过调用open成功打开设备文件之后,将需要获取这个参数。
3
We then loop, rescanning the SCSI bus (by echoing a command to a special file in the /proc pseudo-filesystem and calling devfsd) until the root device (/dev/sda1 in my case) is present.