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.
In my case, the emulated FireWire SCSI bus in question is 1 0 0, but it doesn't hurt to try a few others — if you know which one you will be using, you can tailor the script.
In fact, in order to realize image data real-time collecting and rapid storage, uniting PCI bus and SCSI bus which make system hold high speed data throughput provides sufficiency observation data.