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Browse Prior Art Database

Multiple Indexes for Disk Servo System

IP.com Disclosure Number: IPCOM000062187D
Original Publication Date: 1986-Oct-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 2 page(s) / 81K

Publishing Venue

IBM

Related People

Kisaka, M: AUTHOR

Abstract

The present structure provides a number of index signals during a rotation of data disks so that data tracks on different surfaces of the disks begin at different positions in order to record servo data at different areas on the different disk surfaces. The disk drive can read the servo data from a disk which is nearest to a read/write head when the servo operation is requested. The time needed for servo operation can be reduced since the disk drive reads the nearest servo data, whereby the average access time can be reduced. As shown in Fig. 1, two data disks are coaxially connected to and rotated by a spindle motor. Each disk has upper and lower surfaces A, B or C, D on which data tracks are provided. The index signal is used to indicate the beginning of the data track.

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Multiple Indexes for Disk Servo System

The present structure provides a number of index signals during a rotation of data disks so that data tracks on different surfaces of the disks begin at different positions in order to record servo data at different areas on the different disk surfaces. The disk drive can read the servo data from a disk which is nearest to a read/write head when the servo operation is requested. The time needed for servo operation can be reduced since the disk drive reads the nearest servo data, whereby the average access time can be reduced. As shown in Fig. 1, two data disks are coaxially connected to and rotated by a spindle motor. Each disk has upper and lower surfaces A, B or C, D on which data tracks are provided. The index signal is used to indicate the beginning of the data track. The servo data is recorded on the speed tolerance gap which corresponds to an area between the beginning and end of the data track. A magnet is provided on the rotor of the spindle motor. Four sensors are provided near the motor to generate four different index signals a, b, c and d in cooperation with the magnet with respect to the disk surfaces A, B, C and D, respectively, during a rotation of the disks. As shown in Fig. 2, the index signals a, b, c and d define the beginnings of the data tracks at different positions on the different disk surfaces A, B, C and D, respectively. Therefore, the servo data is recorded at different areas on the different surfa...