In accordance with the invention, {TAIL ~ a range} of possible threshold voltages for a memory cell in a multibit per cell memory is divided into allowed states associated with data values and forbidden zones between {HEAD ~ the allowed states} 
In accordance with the invention , { TAIL ~ a range } of possible threshold voltages for a memory cell in a multibit per cell memory is divided into allowed states associated with data values and forbidden zones between { HEAD ~ the allowed states }
OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL 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 HEAD HEAD HEAD HEAD HEAD HEAD HEAD