MULTILEVEL AND THREEDIMENSIONAL NANOMAGNETIC RECORDING - Bio-Inspired and Nanoscale Integrated Computing - page 178

technologies to start to prosper first overseas, as it is often easier to launch new
standards because of the lack of a well established traditional technology
infrastructure. It could be noted that though the ML technology by Calimetrics
offered only eight signal levels and was not rewritable, it still appeared successful,
especially for its tremendous impact on modern DVD technologies.

6.2.3. Apparent Differences Between ML Magnetic Versus
ML Optical Technology
First, the ML technology developed by Calimetrics competed in the market of
DVD/CD technologies, while the analyzed ML magnetic technology, at least at
this early stage, targets the market of hard drives. Second, the Calimetrics
technology was optics-based, while the currently proposed technology is mag-
netics-based. Consequently, the magnetic technology would be rewritable, is in
contrast with the read-only Calimetrics technology. Finally, the optical technol-
ogy used only eight signal levels while the ML magnetic technology has the
potential for many more levels.

6.2.4. Magnetics of Multilevel 3D Recording
The concept of three-dimensional (3D) magnetic recording was proposed over 10
years ago [14, 15].

6.2.4.1. Background. Traditionally, scaling laws have been followed to
advance magnetic data storage industry to a next level/generation. Scaling implies
that with each next generation, all dimensions of a recording system have been
respectively reduced, as schematically illustrated in Figure 6.2.
Such a straightforward approach (of scaling) has been applied since the
inception of the data storage industry more than five decades ago.

Magnetizing
coil

MR reader

Inductive
“ring” writer

Scaling

S N N S S N N S S N N S

Write field Recording media

Figure 6.2. Schematic diagram illustrating how scaling has been applied to
advance a technology to a next generation for the last five decades.