DESCRIBING MAIN AND MAJOR

The Tape
There are two parts to any audio magnetic recording system: the recorder itself (which also acts as the playback device) and the tape it uses as the storage medium.
The tape itself is actually very simple. It consists of a thin plastic base material, and bonded to this base is a coating of ferric oxide powder. The oxide is normally mixed with a binder to attach it to the plastic, and it also includes some sort of dry lubricant to avoid wearing out the recorder.
Iron oxide (FeO) is the red rust we commonly see. Ferric oxide (Fe2O3) is another oxide of iron. Maghemite or gamma ferric oxide are common names for the substance.
This oxide is a ferromagnetic material, meaning that if you expose it to a magnetic field it is permanently magnetized by the field.
The Tape Recorder
The simplest tape recorders are very simple indeed, and everything from a Walkman to a high-end audiophile deck embodies that fundamental simplicity.