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Browse Prior Art Database

Disk Cartridge Indicators

IP.com Disclosure Number: IPCOM000040186D
Original Publication Date: 1987-Oct-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Kulakowski, JE: AUTHOR [+2]

Abstract

Sensible holes extending through an optical disk cartridge determine if the cartridge is enclosing a read-only disk, a write-once disk, or an erasable disk. As a result, drive sense bits are generated that can be interrogated by a controller to determine what type of disk is present in the drive. Since different types of media (one-sided, doubled-sided either read-only or write-once or erasable) can be inserted into the same optical drive, a detection method is needed to assure read-only media will not be written to or write-once media will not be rewritten. One method for assuring this is to have holes in the optical disk cartridge which can be sensed by optical or mechanical sensors. This information is then stored in the drive as part of the drive sense-bit definition. The figure is a top view drawing of a cartridge.

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Disk Cartridge Indicators

Sensible holes extending through an optical disk cartridge determine if the cartridge is enclosing a read-only disk, a write-once disk, or an erasable disk. As a result, drive sense bits are generated that can be interrogated by a controller to determine what type of disk is present in the drive. Since different types of media (one-sided, doubled-sided either read-only or write-once or erasable) can be inserted into the same optical drive, a detection method is needed to assure read-only media will not be written to or write-once media will not be rewritten. One method for assuring this is to have holes in the optical disk cartridge which can be sensed by optical or mechanical sensors. This information is then stored in the drive as part of the drive sense-bit definition. The figure is a top view drawing of a cartridge. The lack or presence of two holes 1,2 to encode the possibilities of disk media is as follows: Hole 1 Hole 2

Read Only No Hole Hole Write Once

No Hole No Hole Erasable Hole

Hole Selection of the presence or the lack of a hole is important in the definition. If holes are inadvertently closed, the disk should not appear as an erasable disk. Thus, the erasable disk cartridge is defined as the one having two sensible holes. This assures that a write-once disk does not get rewritten, therefore destroying data.

The holes 1 and 2 are on one face of the cartridge, while holes 1' and 2' are on the opposite face and side of the car...