Browse Prior Art Database

Diskette Media Load Detection Algorithm for 5-1/4-Inch Diskette Technology

IP.com Disclosure Number: IPCOM000034472D
Original Publication Date: 1989-Feb-01
Included in the Prior Art Database: 2005-Jan-27
Document File: 2 page(s) / 73K

Publishing Venue

IBM

Related People

Crandall, DR: AUTHOR [+3]

Abstract

This article describes a technique for detecting whether a medium has been inserted in a previously idle diskette drive. Many existing programs require a special interrupt from the system to alert them that a diskette has been inserted and the drive is ready. This interrupt was supplied by the 8-inch diskette technology. 5-1/4- inch diskette technology does not automatically supply this interrupt. Accordingly, the technique disclosed herein was developed to supply this interrupt so that existing programs would not have to be updated to accommodate the new diskette technology. Since the 5-1/4-inch diskette technology only informs the user that a diskette media has been inserted or removed, the task of finding out if the diskette media was inserted and the drive ready (meaning that the door had been closed) required solution.

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Diskette Media Load Detection Algorithm for 5-1/4-Inch Diskette Technology

This article describes a technique for detecting whether a medium has been inserted in a previously idle diskette drive. Many existing programs require a special interrupt from the system to alert them that a diskette has been inserted and the drive is ready. This interrupt was supplied by the 8-inch diskette technology. 5-1/4- inch diskette technology does not automatically supply this interrupt. Accordingly, the technique disclosed herein was developed to supply this interrupt so that existing programs would not have to be updated to accommodate the new diskette technology. Since the 5-1/4-inch diskette technology only informs the user that a diskette media has been inserted or removed, the task of finding out if the diskette media was inserted and the drive ready (meaning that the door had been closed) required solution. This is accomplished through the use of a microcode routine executed within the diskette controller subsystem, completely transparent to the system operation, that is activated by a diskette being inserted or removed from a drive. Once activated the diskette subsystem checks the drive to see if it is ready and if so issues an interrupt to the system to indicate that the diskette was loaded. If the drive is not ready, the routine terminates without issuing an interrupt. The drawing is a flow chart of the load detection algorithm of this disclosure. This special routine is kicked off by a hardware interface output line called "diskette change". In 5-1/4-inch diskette technology the drive has a sensor that detects when a diskette has been moved past it. This turns on "diskette change". Either inserting or removing...