All video images begin as a form of light, which is then converted to electrical signals. These electrical signals can then be converted to either a magnetic or optical signal for purposes of recording or storage. The two primary methods used to record or store video are magnetic recording, as in videotape, or optical recording, as in DVDs. This chapter will deal with magnetic recording and media.
Magnetic media is based on the physics principle that electricity, or electrical signals from a converted light source, that passes through a wire, creates a magnetic field around the wire. If that wire is wrapped around a soft iron core, that iron core will become an electromagnet (Figure 16.1). The process ...