Dual Erase Width Magnetic Read/Write Head
Original Publication Date: 1985-Mar-01
Included in the Prior Art Database: 2005-Feb-18
Backward read/write (R/W) compatibility between floppy diskette drives of different track density (e.g., updating a 48-track-per-inch (tpi) diskette on a 96-tpi drive) is a useful function, but is difficult to achieve reliably. For example, combined write-plus-erase width for a 96-tpi drive is approximately the same dimension as the R/W width alone for a 48-tpi drive. If track radii are not identical for writing 48-tpi and for updating 96-tpi drives, a fraction of the 48-tpi written track (approximately equal to track centerline misregistration between two different disk drives) will not be erased. This unerased band can cause unrecoverable read errors in a 48-tpi drive, depending on track centerline misregistration.