Browse Prior Art Database

Diskette

IP.com Disclosure Number: IPCOM000048003D
Original Publication Date: 1983-Dec-01
Included in the Prior Art Database: 2005-Feb-08
Document File: 2 page(s) / 16K

Publishing Venue

IBM

Related People

Alstad, JK: AUTHOR [+4]

Abstract

A small diskette comprises a four-inch diameter floppy magnetic recording disk and a rigid plastic envelope formed of electrically conductive plastic. The data error rates, which may be experienced when reading floppy magnetic recording disks, are a function of the electrostatic charge which accumulates on the disk as a result of its operational mode which requires periodic stopping and high speed rotation between the stop intervals. Data errors occur as a result of debris which is attracted to the disk's surface by electrostatic charge. A number of diskettes use hard, plastic jackets to encase and protect the floppy disks. In these diskettes, data errors can be reduced by using an electrically conductive plastic when molding the diskette's outer jacket.

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Diskette

A small diskette comprises a four-inch diameter floppy magnetic recording disk and a rigid plastic envelope formed of electrically conductive plastic. The data error rates, which may be experienced when reading floppy magnetic recording disks, are a function of the electrostatic charge which accumulates on the disk as a result of its operational mode which requires periodic stopping and high speed rotation between the stop intervals. Data errors occur as a result of debris which is attracted to the disk's surface by electrostatic charge. A number of diskettes use hard, plastic jackets to encase and protect the floppy disks. In these diskettes, data errors can be reduced by using an electrically conductive plastic when molding the diskette's outer jacket. The charge-bleedoff rate t, which should be no longer than the time it takes for one disk revolution, can be calculated using the formula Q=Qoe-t/t where Qo is the charge carried by the disk at time zero Q is the charge carried by the disk at a later time t t is the relaxation time, and is a function of the resistivity of the plastic used in molding the diskette's outer jacket. Using this formula, it can be calculated that a suitable plastic should have a resistivity less than 1012 ohms/cm . A representative plastic is BENSTAT* polystyrene. * Trademark of Bengal Inc.

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