Depending on the desired approach, different types of calibration may be performed on a given unit of memory. For example, “normal calibration” may be performed by reading all pages in the unit of memory (e.g., block of non-volatile memory) with a small set of different threshold voltage shift levels. Furthermore, the number of read operations performed per page of the unit of memory is preferably minimal, e.g., typically 3 read operations.

Alternatively, “fast calibration” includes a calibration method in which a limited amount of pages are read (e.g., at least a number of pages less than read using a normal calibration process) in order to perform the calibration process on a unit of memory. By limiting the number of pages read during fast calibrations, the number of read operations performed is significantly reduced compared to normal calibration processes.

Further still, “extensive calibration” performs read operations using a large set of different threshold voltage shift values as would be appreciated by one skilled in the art upon reading the present description. For example, in some approaches, the large set of different threshold voltage shift values may preferably include all possible threshold voltage shift values. Extensive calibration processes may be desired when the previous threshold voltage shift values are either not available or known to be not suitable.