Abstract: A disk drive that can read from and write to both standard floppy disks and high capacity floppy disks. The present invention provides a single slot disk drive that can accept both standard floppy disks and high capacity floppy disks. After a floppy disk is inserted, physical cues on the floppy disk are used to inform the disk drive as to the nature (standard or high capacity) of the inserted disk. The disk drive incorporates two interfaces, a standard floppy disk controller and an IDE interface for high capacity disks. The disk drive is configured so that both interfaces can communicate with a host computer at all times, regardless of what type of disk is inserted in the disk drive. This allows the host computer to operate as if it had two separate disk drives available.

Abstract: The present invention describes a time based servo pattern scheme which provides position and velocity information with high accuracy. A plurality of servo lines are formed on a data disk extending from the inner track to the outer track. In the preferred embodiment of the present invention, these lines are employed as part of a buried servo scheme such that the entire useable disk surface is dedicated to data storage. The servo pattern is written on each side of the disk so that, if the disk were transparent, the respective servo lines would appear to intersect when viewed from above. Servo heads located on each side of the disk detect servo line crossings. By comparing the time difference between crossings of corresponding tracks on either side of the disk, the radial position of the heads can be determined. Therefore, even when nominal track centers do not fall on servo line intersections, their position can be determined accurately.

Abstract: The present invention describes a time based servo pattern scheme which provides position and velocity information with high accuracy. A plurality of servo lines are formed on a data disk extending from the inner track to the outer track, In the preferred embodiment of the present invention, these lines are employed as part of a buried servo scheme such that the entire useable disk surface is dedicated to data storage. The servo pattern is written on each side of the disk so that, if the disk were transparent, the respective servo lines would appear to intersect when viewed from above. Servo heads located on each side of the disk detect servo line crossings. By comparing the time difference between crossings of corresponding tracks on either side of the disk, the radial position of the heads can be determined. Therefore, even when nominal track centers do not fall on servo line intersections, their position can be determined accurately.

Abstract: Data is so recorded in tracks of a first radially disposed zone of a disc that the minimum bit length limit is not exceeded within the innermost track of the zone and, in another more inwardly radially disposed record zone (or zones) of the disc, the quantity of data recorded in the tracks thereof is binarily reduced so as again not to exceed the minimum bit length limit within the innermost track of the second zone, etc.