The Elmsford, New York-based Fuji USA unit of Fuji Photo Film of Japan is offering 3.5 floppy disks that store 1Mb a side, and says that it will have 4Mb and 8Mb disks ready within the next few months. The key to packing such high capacities onto such a small disk is a new coating process called Beridox, which involves sputtering superfine, high-coercivity Barium-Ferrite and Cobalt-Chromium particles about half the size of conventional particles onto polymer surfaces. The particle coatings are about one micron thick, half that of ordinary magnetic coatings. Coercivity is 700 Oersted, compared with 600 Oersted for current high-density disks and the new Fuji disks also have 80 tracks per side, compared with 40 tracks per side for 5.25 floppies. Fuji uses RD binding, where particles are suspended in a coating material to ensure even bonding to the polymer base. Drives to use the new disks are expected this year.
