In accordance with the invention, 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 {HEAD ~ forbidden zones} between {TAIL ~ the allowed states} 
between
In accordance with the invention , 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 { HEAD ~ forbidden zones } between { TAIL ~ the allowed states }
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 OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL