Multi-Track-Density Floppy Disk System
Original Publication Date: 1984-Mar-01
Included in the Prior Art Database: 2005-Feb-03
The desire in the floppy disk industry is to get more tracks per inch on a disk without significantly increasing the cost. The primary problem that limits the number of tracks per inch is the expansion of the disk with temperature and humidity. The 8-inch disks typically use 48 tracks per inch (TPI), the 5-inch disks are at 96 TPI, and the 3-inch disks approach 150 to 200 TPI; the smaller the disk the higher the track density because the amount of linear expansion of the disk is smaller. The system to be described is one in which two or more track densities are written on the same disk, with the outer tracks being further apart than the inner tracks. For example, one configuration could be on an 8-inch disk where the tracks from 8 inches to 5 inches are 48 tracks per inch and those from 5 inches to the inner track are 96 TPI.