Browse Prior Art Database

Detection of Diskette Change

IP.com Disclosure Number: IPCOM000044287D
Original Publication Date: 1984-Dec-01
Included in the Prior Art Database: 2005-Feb-05
Document File: 2 page(s) / 22K

Publishing Venue

IBM

Related People

Ashbee, WH: AUTHOR [+3]

Abstract

In the use of diskette drives for data storage, it is often necessary to signal the using system that the diskette being used has been removed and a new one placed in the drive. The write-protect sensor may be used to detect the disk change. Since the write protect sensor can be an optical device, its reliability is higher than that of an electro-mechanical device which is typically used to sense a disk change. The method relies on monitoring the write protect line for the dark-to-light transition in the write protect WRP signal. This transition corresponds to the trailing edge of the diskette jacket as the diskette is removed from the drive. When this transition occurs (A), a disk change CHG is signalled to the using system. The signal is cleared (B) on the first valid access command STEP following the signal.

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Detection of Diskette Change

In the use of diskette drives for data storage, it is often necessary to signal the using system that the diskette being used has been removed and a new one placed in the drive. The write-protect sensor may be used to detect the disk change. Since the write protect sensor can be an optical device, its reliability is higher than that of an electro-mechanical device which is typically used to sense a disk change. The method relies on monitoring the write protect line for the dark- to-light transition in the write protect WRP signal. This transition corresponds to the trailing edge of the diskette jacket as the diskette is removed from the drive. When this transition occurs (A), a disk change CHG is signalled to the using system. The signal is cleared (B) on the first valid access command STEP following the signal. This method avoids the problem of signaling the same change multiple times, while assuring that any disk change will be seen.

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