A method, a computer readable medium and a memory controller. The method for writing information to a K-level memory unit, includes: receiving a sequence of information bits; generating an information value that represents the sequence of information bits; applying a first function to the information value, to provide a first function result; selecting a first cell of the K-level memory unit as a current cell; wherein K is a positive integer that is greater than 1; writing the first function result to the first cell; and repeating the stages of: (a) reading a current cell to provide a current read result; (b) applying a second function to the current read result and to a function result that was written to the current cell, to provide a second function result; (c) selecting another cell as a current cell; and (d) writing the second function result to the current cell.