Browse Prior Art Database

Zone Recording Flexible Diskette Drive Via Microprocessor Control

IP.com Disclosure Number: IPCOM000052028D
Original Publication Date: 1981-Apr-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Herald, RF: AUTHOR [+2]

Abstract

Due to the nature of diskette recording, outer disk tracks are longer than inner tracks. The disk angular velocity and data rate have traditionally been constant. Zone recording is an attempt to maintain constant bit density by decreasing angular velocity or increasing the recording frequency, as the read/write head moves to the outer tracks. Zone recording involves partitioning the disk surface on which information is stored in concentric tracks, into groups of adjacent tracks to form zones. Within these zones either write frequency or disk speed is constant. Between zones they change. The smaller the zone in terms of the number of tracks within it, the less variation of flux changes per inch within a zone. A greater number of zones results in more angular speed changes.

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Zone Recording Flexible Diskette Drive Via Microprocessor Control

Due to the nature of diskette recording, outer disk tracks are longer than inner tracks. The disk angular velocity and data rate have traditionally been constant. Zone recording is an attempt to maintain constant bit density by decreasing angular velocity or increasing the recording frequency, as the read/write head moves to the outer tracks. Zone recording involves partitioning the disk surface on which information is stored in concentric tracks, into groups of adjacent tracks to form zones. Within these zones either write frequency or disk speed is constant. Between zones they change. The smaller the zone in terms of the number of tracks within it, the less variation of flux changes per inch within a zone. A greater number of zones results in more angular speed changes. A constant rate of flux changes per inch can result in a lower-cost read channel due to not having to make adjustments for bit spreading and crowding through filter and write current switching.

Zone recording may be accomplished using a single low-cost integrated circuit microprocessor for drive control. The processor allows digital motor speed control and constant flux changes per inch recording to be included with virtually no additional cost. In an application which accesses the drive infrequently, an easily controllable brush DC motor may be used as the spindle motor. In a minimum performance drive, access speed is not critica...