Tracking cells are used in a memory system to improve the read process.
The tracking cells can provide an indication of the quality of the data
and can be used as part of a data recovery operation if there is an
error. The tracking cells provide a means to adjust the read parameters
to optimum levels in order to reflect the current conditions of the
memory system. Additionally, some memory systems that use multi-state
memory cells will apply rotation data schemes to minimize wear. The
rotation scheme can be encoded in the tracking cells based on the states
of multiple tracking cells, which is decoded upon reading.