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Error Recovery Procedure for an Automated Library

IP.com Disclosure Number: IPCOM000087293D
Original Publication Date: 1977-Jan-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Carnes, ML: AUTHOR [+2]

Abstract

Erroneous reporting of higher level errors in an automated library having one or more accessors or robots to fetch and to store articles is eliminated by testing that such an error is not caused by sensor failure or accessor malfunction. The accessor detecting the error is removed from the storage area and marked "suspect" by the controller. The other accessor is then directed to perform the same operation. Should the other accessor discover the same error, the first accessor is made useable again and the error is reported as a higher level error. Should the other accessor successfully complete the operation, the first accessor is marked unusable, and the error is assumed to be an accessor failure and is reported as such.

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Error Recovery Procedure for an Automated Library

Erroneous reporting of higher level errors in an automated library having one or more accessors or robots to fetch and to store articles is eliminated by testing that such an error is not caused by sensor failure or accessor malfunction. The accessor detecting the error is removed from the storage area and marked "suspect" by the controller. The other accessor is then directed to perform the same operation. Should the other accessor discover the same error, the first accessor is made useable again and the error is reported as a higher level error. Should the other accessor successfully complete the operation, the first accessor is marked unusable, and the error is assumed to be an accessor failure and is reported as such.

Occasionally, the system issues an order for storing an article in a cell which is already occupied. To solve this problem, the article is stored in a "reserve cell" (one is defined for each accessor) which is maintained in an available or empty state. The article is then fetched by the other accessor and, in the event of a sustained failure, is available to the higher level controller for further action.

Should one of the accessors fail, in order to prevent damage to either the accessor and/or the cartridge, the Y or vertical position of the accessor is observed as servo power is removed. If the mechanism falls (under the force of gravity), subsequent powered motion will not cause damage and the...