Method and apparatus for rewriting on a magnetic disk on which data has

Abstract

A floppy disk drive (FDD) capable of data transfer with a track density of, typically, 96 tracks per inch (TPI) is adapted for rewriting on a floppy disk on which data has been written on concentric data tracks by a 48-TPI FDD. The data tracks, each with a width W1, are arranged with a pitch P1 on the disk. The 96-TPI FDD has a magnetic head assembly comprising a read/write head capable of providing a data track width W2 of 0.4 W1 to 0.6 W1, and a pair of tunnel erase heads each capable of providing an erase width of (W1-W2)/1 to (P1/2-W2). The opposite edge portions of each prewritten data track on the disk are erased by the erase heads of the head assembly, with the latter successively positioned intermediate the data tracks. Either before or, preferably, after the erasure of the edge portions of the prewritten data tracks, the head assembly is positioned on the successive data tracks for rewriting thereon by the read/write head, with the erase heads maintained in operation for the complete erasure of the old data during the writing of new data.