{HEAD ~ The disk drive} provides a non volatile backup for the random access memory by transferring data between the disk drive and random access memory automatically, or by command, on {TAIL ~ a non realtime basis} 
{ HEAD ~ The disk drive } provides a non volatile backup for the random access memory by transferring data between the disk drive and random access memory automatically , or by command , on { TAIL ~ a non realtime basis }
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL