Devices and methods for storing data

A data-storage device, comprising:

• a medium comprising a surface;
• a plurality of data-containing loci arranged on the surface, the loci including respective holes extending respective depths into the medium, the respective depths being different in at least some of the data-containing loci, wherein the respective depth of a data-containing locus corresponding, at least in part, to a respective unit of data contained in the locus;
• wherein each hole contains a respective amount of magnetically responsive particles, the amounts being different among at least some of the loci and being magnetically readable;
• wherein at least some of the loci also have a light-affecting property, of which respective values are different among some of the loci and are optically readable;
• and
• wherein the magnetically responsive particles in respective holes of a first group of the loci are of a first type and the magnetically responsive particles in respective holes of a second group of the loci are of a second type different from the first type sufficiently to confer different respective shades of magnetic response of the second group compared to the first group.

A data-storage device, comprising:

• a medium having a surface;
• and
• a plurality of multiple, discrete, data-containing loci arranged on the surface, each data-containing locus having a respective dimension on the surface that is different in at least some of the loci, the respective dimension corresponding to a respective unit of data contained in the locus;
• wherein each data-containing locus includes a respective amount of magnetically responsive particles, the amounts being different among at least some of the loci and being magnetically readable;
• and
• wherein at least some of the loci also have a light-affecting property, of which respective values are different among some of the loci and are optically readable;
• wherein the magnetically responsive particles of a first group of the loci are of a first type and the magnetically responsive particles of a second group of the loci are of a second type different from the first type sufficiently to confer different respective shades of magnetic response of the second group compared to the first group.

A method for storing data, comprising:

• providing a supportive medium having a surface;
• distributing the data into multiple data units, wherein each data unit is representable as a respective amount of magnetically responsive particles such that at least some of the data units have different respective number of particles;
• and forming, on the surface, an arrangement of multiple data-containing loci and providing each such locus with a respective amount of magnetically responsive particles corresponding to its respective data unit, thereby storing the respective data units in the loci, providing each locus with a respective amount of magnetically responsive particles comprises providing each locus with magnetically responsive particles of a respective type selected from a range of multiple selectable types;
• the types of particles are different in at least some of the loci;
• and the types in the range differ from each other by at least one characteristic selected from the group consisting of material type, particle size, particle shape, particle density, and particle distribution, wherein providing the loci with respective amounts of magnetically responsive particles comprises:
• suspending the magnetically responsive particles in a carrier fluid;
• introducing respective amounts of the suspension of the loci;
• and curing the suspension.