A semiconductor memory device is capable of writing data in phase with external data to a memory cell regardless of which memory cell the data is written to. The head slider comprises a first recess on the air bearing surface of the head slider. In such an aspect in which the communications device determines that the measured power level of the NACK is above a threshold power level, the communications device may act as a relay and transmit the first packet during the second timeslot. Related devices are also discussed. The dust particles are collected in a separate vessel, which is mounted in a flow of air from the dust collection conduit and an exhaust fan. The receiver includes a first receiving unit operable to receive identifying information for multicast data from a base station and a second receiving unit operable to receive the data on a shared channel from the base station by the information received.