What is "bubble memory"

n. (context computing English) A type of non-volatile computer memory that uses a thin film of magnetic material to hold small magnetized areas, known as bubbles or domains, each storing one bit of data.

Bubble memory is a type of non-volatile computer memory that uses a thin film of a magnetic material to hold small magnetized areas, known as bubbles or domains, each storing one bit of data. The material is arranged to form a series of parallel tracks that the bubbles can move along under the action of an external magnetic field. The bubbles are read by moving them to the edge of the material where they can be read by a conventional magnetic pickup, and then rewritten on the far edge to keep the memory cycling through the material. In operation, bubble memories are similar to delay line memory systems.

Bubble memory started out as a promising technology in the 1980s, offering memory density of a similar order to hard drives but performance more comparable to core memory. This led many to consider it a contender for a "universal memory" that could be used for all storage needs. However, the introduction of dramatically faster semiconductor memory chips pushed bubble into the slow end of the scale, and equally dramatic improvements in hard drive capacity made it uncompetitive in price terms. Bubble memory was used for some time in the 1970s and 80s where its non-moving nature was desirable for maintenance or shock-proofing reasons. The introduction of Flash RAM and similar technologies rendered even this niche uncompetitive, and bubble disappeared entirely by the late 1980s.