Patent ID: 6785588
Filing Date: 2004-08-31
Classification: G06F,G11B

Abstract:
A method to provide failover protection in a data storage and retrieval system in the event of an accessor failure, wherein said data storage and retrieval system includes a garage, one or more portable data storage media, two or more moveable accessors, and two or more accessor controllers, wherein said two or more accessors can communicate with one another, and wherein each of said two or more accessors comprises an accessor controller and a work queue stored in that accessor controller, and wherein said two or more accessors include a first accessor and one or more remaining accessors, said method comprising the steps of:providing a work request to each of said two or more accessors; creating by each of said two or more accessor controllers a pending work entry comprising said work request; adding said pending work entry to the work queue stored in each of said two or more accessor controllers; communicating a notification from said first accessor to said one or more remaining accessors that said first accessor is initiating said vending work entry; acknowledging said notification by each of said remaining accessors; determining if said first accessor reports completion of said vending work entry; determining if said first accessor can communicate with said one or more remaining accessors; determining if said first accessor has completed said pending work entry; and determining if said first accessor has a portable data storage medium releaseably attached thereto.