SPM based recording toward ultrahigh density recording with trillion bits/inch/sup 2/

Nano-indentation type AFM (atomic force microscopy) based storage is presented. Particularly, I discuss the possibility of ultrahigh density storage using nano-writing bits with a diameter of tens nanometers for 1 trillion bits/in/sup 2/, high speed readout at over megahertz, and inner-division type nano-tracking.