1. A method for storing and retrieving operational data in a control system having a RAM memory and a flash memory, the method comprising. switching on the control system; supplying a backup value for only some of the operational data in the control system; and storing each backup value in the RAM memory, without accessing the flash memory; subsequently obtaining most recent operational data of at least one data type from the flash memory; and storing the most recent operational data of the at least one data type in the RAM memory.