A content based messaging audio and video conferencing system provides a messaging infrastructure for multimedia and collaborative applications. The method may include storing a presence vector in a directory of a memory slice, said presence vector indicating whether a line in local memory has been cached. A resistive feedback circuit is coupled to the CMOS inverter amplifier for cancelling an offset voltage that is associated with the CMOS inverter amplifier. The plastic piece is formed by injection molding and a through hole is formed at center thereof. The chains receive the high supply voltage and switch it to output the differential high-voltage output signal. The first inner race is attached to the motor shaft.