The present invention concerns a method for controlling an output voltage of a boost converter composed of n bridge devices connected in series, each bridge device being composed of plural switches and a capacitor, the switches being controlled by periodical patterns decomposed in time intervals. The second interconnect includes a barrier layer formed on the second insulating film, and a plated layer formed on the barrier layer. One driver may be active when an input signal has a first transition, but not a second transition. A means for assigning a total number to a plurality of simultaneously recorded or reproduced data streams as well assigning individual data stream numbers allows informing the disk device of the throughput required by the host.