In {HEAD ~ one embodiment}, {TAIL ~ an optimal sequence} of data movements depends on the storage system objectives 
In { HEAD ~ one embodiment } , { TAIL ~ an optimal sequence } of data movements depends on the storage system objectives
OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH