A micro-electro-mechanical systems (MEMS) device is presented that can read very high density magnetic media and very high density CD ROMs. Both the magnetic and optical read heads comprise one or more cold cathode MEMS e-beam cells. The e-beams are deflected according to the data bit being interrogated and the state of that bit is determined by a detector. Large arrays of such cells can simultaneously read large areas of the memory media. Arrays of such MEMs detectors can comprise a plurality of "steerable" e-beam emitters that can be directed to interrogate specific data sites on the magnetic media. Thus, in some cases, the media can remain stationary. Densities of 200 gigabits per square inch or more and read speeds greater than 1000 times faster can be achieved.