A method of converting an abstract quality of service policy into a new configuration for one or more network devices of managed network, as routers. At least one digit line other than the first and second digit lines is driven to a reference voltage level and the at least one digit line is coupled to the second digit line to establish a reference voltage in the second digit line. The computation block may be coupled to a pulse width generator for generating signals having pulse widths that are integer multiples of the high-frequency oscillator period. The frequency divider is used to divide the frequency of the clock signal for generating a reference clock signal. the three-note blues progression I, IV, V, for preceding the groups of information, respectively. When the drawing section arrives at the pick-up point, the head lowers again from the stand-by position.