A high density computer memory which utilizes a probe operating with two degrees of freedom over a memory area, the probe location altered by drive systems incorporating piezoelectric elements arranged to drive the probe parallel to the plane of the memory surface. Sensors to provide an indication of the location of the probe independent of the drive system are provided. The memory system incorporates an underlying substrate upon which is deposited one of a variety of elements or compounds chosen to effect a change in physical-chemical properties when a data bit is written on the surface. The probe is moved over the surface at a distance which produces a current from Schottky or Field effect.