the invention pertains to a head - disk assembly device , “ mass spin - valve ” or “ gravitational rectifier ” and method of producing gravitomagnetic induction utilizing nano - features ; nano - bumps and nano - pits ; fabricated on the surface of a hard disk . the device includes a computer hard disk ; a piezoelectric glide head and / or a gmr read head ; a typical hard drive &# 39 ; s electronics ; wherein , defects are fabricated on the said disk using a focused ion beam by depositing requisite number of nanobumps of specified height , and etching equal number of nanopits of specified depth a few mils or mm apart on a pre - decided radius . by spinning the said nano - features disk produce an associated mechanical force utilizing a piezoelectric glide head and / or an associated magnetic force utilizing a gmr read head ; for general use in surface characterization work and for producing power by the presence or the absence of matter on a spinning disk .