Explain Working Principle And Construction Of Magnetic Core Memory?

Before discovering of silicon chips, magnetic core memory was used in computers. Core memory consisted of tiny circular object with a hole of diameter less than 0.01 inch called cores. Cores were made of ferromagnetic material. The magnetic core memory could retain data even when power was switched of. It was non volatile memory. A basic principle of physical states that when electric current passes through a wire threading a core, the core is magnetized in a certain direction. The direction of magnetizing depends the direction of the flow of current through wire.

Flow of current in one direction magnetizes a core in clockwise direction. This means that a core can be in either of two states, clockwise direction or anti clock wise direction. Each state of the core represents a binary digit or a bit.

In core memory, magnetic cores were threaded by a screen of wires. The cores were arranged in such a manner that each core was threaded by two wires. The two wires were kept perpendicular to each other. The magnetic cores were stacked in parallel planes for storing of data. If computer used 12-bit storage, the magnetic cores would have 13 planes. 12 planes were actual storing of and 13th plane was used as parity bit.