0325056-A2 is referenced by 43 patents.
A digital data storage device comprises a conductive probe having a tip closely spaced from, and movable relative to, a flat storage surface exposed to a fluid containing a plurality of discretely attachable molecules. The probe is selectively pulsed to cause molecules to be captured from the fluid and removably attached to selected sites on said surface to write data bits at said sites in the form of surface irregularities. To read the bits so written, the probe and substrate are voltage biased to cause a tunnel electron current to flow between the probe tip and surface; whereupon variations in said current (and/or tip position if the tip is feedback-controlled to maintain a constant distance above the surface) are measured and detected to denote the states of the bits.; The bits are selectively erased by energising the probe with a pulse of appropriate voltage, thereby detaching molecules at selected sites without damage to the surface for restoring the surface at said sites substantially to its original flat configuration. A low bias voltage is maintained between the tip and storage surface during reading.