bubble memory

A storage device built using materials such as gadolinium

gallium garnet which are can be magnetised easily in only one

direction. A film of these materials can be created so that

it is magnetisable in an up-down direction. The magnetic

fields tend to join together, some with the north pole facing

up, some with the south.

When a veritcal magnetic field is imposed on this, the areas

in opposite alignment to the field shrink to circles, or

'bubbles'. A bubble can be formed by reversing the field in a

small spot, and can be destroyed by increasing the field.

Bubble memory is a kind of non-volatile storage but

EEPROM, Flash Erasable Programmable Read-Only Memory and

ferroelectric technologies, which are also non-volatile, are

faster.

["Great Microprocessors of the Past and Present", V 4.0.0,

John Bayko [email protected], Appendix C]

(1995-02-03)