Recording characteristics for Ba ferrite floppy disk

This article is mainly concerned with the overwrite characteristics of Ba-ferrite floppy disks. The major conclusions are as follows. (1) In order to obtain an adequate overwrite level in a floppy disk/disk drive system with an optimum recording wavelength of 1.5 μm, the magnetic layer thickness must be roughly 0.4 μm or less. This is true regardless of whether a ferrite head or a MIG head is used, and independent of the head gap length. (2) The output, peak shift, resolution, overwrite and other recording parameters depend on the medium magnetic layer thickness when the latter is 0.5 to 0.6 μm or less. (3) In partial penetration recording, when the overwrite magnetic field is weaker than the prerecorded signal field, the OWM rapidly deteriorates. This in turn gives rise not only to shifts in magnetization transitions, but to the generation of extra bits as well . (4) The pre-erase method is capable of resolving the problem of overwriting in partial penetration. Bit asymmetry is small even when using dc erasure. Pre-erase method is also effective for ensuring downward-compatibility.