Today I read a paper titled “Hard Disk Drive as a Magnetomechanical Logic Device”
The abstract is:
We consider the conditions how two binary numbers can be superimposed on the same track with the use of different recording magnetic fields.
As a result the average magnetization of longitudinal medium along the track can have three states: -M, 0 and +M.
Possibility to perform logic operations with these states is considered.
We demonstrate OR, AND, XOR and NOT operations and discuss a modification of a recording device.