A differencing generator generates difference data between a first data set and a second data set. This invention also relates to inbred maize lines derived from inbred maize line PH8KG, to methods for producing other inbred maize lines derived from inbred maize line PH8KG and to the inbred maize lines derived by the use of those methods. Data remains in the locking cache until it is specifically overwritten under software control.