A method and a system for a fast and reliable color reduction from multiple bit color representations to 4 bit color representations. Treatment is carried out by an implantable signal generator, one or more implantable electrodes for electrically stimulating a predetermined stimulation site of the vagus nerve, and a sensor for sensing characteristics of the heart such as heart rate. The positive electrode comprises a positive electrode active material in a form of secondary particles as aggregates of primary particles of a lithium transition metal oxide. When data in a sector is renewed, the sector’s location and renewal frequency information are saved not only in the sector of the disk media but also in a temporary memory. A line switch control device provides for closing only of the line switches on those local data lines which belong to the segment in which a write or read mode takes place.