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