Recent developments of magnetic film memories in Japan

Magnetic thin-film memories that are now in practical use or under development in Japan are surveyed, and related technical problems are discussed. The main problems include the use of multilayered film for NDRO operation and the improvement on its switching characteristics, the confirmation of reliability of thin films, and the selection of flux keeper for very high density memory. States of art in connection with plated-wire memories, planar-film memories, and semipermanent memories are reviewed, and a new type of closed-flux-path memory of high packing density is also introduced.