Hewlett-packard Company

Colorado Memory Systems, Inc.

James A Imthurn

Kevin L Miller

Eric Martin Krug

Alan J Richards

A computer memory backup device which utilizes standardized computer tape cartridges is disclosed. The focus of the invention is upon the techniques for ascertaining the appropriate placement of such cartridges to allow operation of the computer memory backup device. The device being connected to a computer allows for the determination of a cartridge presence through the use of an optical sensor mechanism. The sensor mechanism includes a light emitting diode (l.e.d.), light pipe and phototransistor. During any time that the cartridge is not in the computer memory device or improperly or incompletely inserted the electromagnetic radiation emitted by the l.e.d. will be directed by the light pipe to the phototransistor. In this manner a negative determination is correctly made. When the cartridge is correctly and completely inserted, the pathway of the electromagnetic radiation is blocked between the light pipe and the phototransistor. In this manner a positive determination is correctly made. To enhance the accuracy of the disclosed device, time domain filtering is used to screen erroneous electromagnetic radiation from causing an incorrect cartridge in determination.

Sysetm for optically sensing the placement of magnetic tape cartridge

A computer memory backup device which utilizes magnetic tape media having aperture indications at the beginning-of-tape (bot) and the end-of-tape (eot) for accomplishing the sensing of the same is disclosed. The present invention utilizes a light pipe for directing the emitted electromagnetic radiation from an isolated source to the magnetic tape media, and focuses the radiation in proximity to the media. An integral focusing lens disposed on the exit end of the light pipe serves to converge the exiting electromagnetic radiation in this fashion. The electromagnetic radiation source, shown as a light emitting diode, is pulsed in a manner such that accuracy, as well as energy conservation, is greatly increased. A time domain filtering method is employed as a means to further enhance the system's accuracy in sensing the beginning-of-tape and end-of-tape. The devices accommodate standard aperture indications as required by ANSI specifications in both dimensional and placement aspects. When these aperture indications reach the area at which the electromagnetic radiation is being focused they permit the electromagnetic radiation to pass through the magnetic tape media at which point the electromagnetic radiation is sensed. A determination is then made appropriately as to either the beginning-of-tape or end-of-tape.

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Rathdrum, ID, United States of America

James A Imthurn