Magnetic Encoding Definition/Meaning:
The method by which binary data is recorded on magnetic media.
In horizontal recording on magnetic disks, tapes, and cards, magnetic domains in
the media are aligned along the direction of the applied magnetic field with
either north or south pole leading: each domain is a tiny bounded region in
which the magnetic moments of the component atoms are aligned, and it therefore
behaves like a magnet. The domains are arranged end to end along a track, which
may be either a concentric ring on a disk or run the length of a tape or card.
There may not be a one-to-one relationship between the binary information of the
data and the orientation of the magnetic domains. See disk format.
In 1975 Shunichi Iwasaki published his work on vertical recording methods. The
magnetic domains are oriented through the thickness of the magnetic film and
have either a north or a south pole at the exposed surface. The magnetic
material is usually a vacuum-deposited film of metal such as an alloy or
combination of cobalt and chromium over a layer of permalloy. Linear densities
as high as 200,000 bits per inch have been demonstrated. Vertical recording can
thus yield an increase of at least 25 times and possibly 100 times the bit
density achievable by current horizontal recording techniques.
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