One embodiment involves having a processor writing disk drive command information for a number of data transactions to cacheable system memory. A microphone comprising the above Sigma Delta Modulator and a cellular phone or hearing aid incorporating the microphone. The received signals and noise are demodulated to produce a demodulated signal. The first and second movable members are movable between a first position in which they protrude out of the support surface and a second position in which the protrusion from the support surface is less than in the first position. , the credit rating of a reference entity.