A hard disk drive is placed within {TAIL ~ a cartridge} which includes {HEAD ~ a second printed circuit board} 
A hard disk drive is placed within { TAIL ~ a cartridge } which includes { HEAD ~ a second printed circuit board }
OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD