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Optimized Utilization of Shelf Space for Tape Volumes in Storage Locations

IP.com Disclosure Number: IPCOM000012154D
Original Publication Date: 2003-Apr-14
Included in the Prior Art Database: 2003-Apr-14
Document File: 2 page(s) / 11K

Publishing Venue

IBM

Abstract

Manage and optimize moves of removable media's between an infinitive number of storage locations

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Optimized Utilization of Shelf Space for Tape Volumes in Storage Locations

  Disclosed is an algorithm to optimize the shelf space for volumes in storage locations.

         Consider an environment with an infinitive number of locations where you can store volumes in a predefined number of slots in storage locations and you are allowed to move any number of volumes between any location. Assume also, that you are only allowed to move volumes when you have an empty slot available in the receiving location. With a high probability you will eventually reach a point where you cannot conduct all the required moves or your shelf space is in a mess, because of empty slots all over the place and the volumes are not in sequence for easy retrieval. Furthermore, if a storage location and therefore each slot, is very expensive, like in a safe, then this situation is even more undesirable. You can find this kind of scenario in todays data processing centers where media's are kept at shelf locations, in automated or manual tape libraries or even in virtual tape libraries managed by a removable media management systems, and where a need exists to move these media's to various offside storage location for either safety or legal reasons.

    When a volume move is required between two locations, a volume occupies a shelf space location in the location were it comes from and were it moves to, unless the move has been physically performed and is confirmed to the removable media management system. As a removable media management system has to support multiple moves between multiple locations and locations have a finite number of identifiable slots, it may occur that a volume is moving to a slot which is still occupied by another volume just about to move. It also could be that there is no vacant slot at the destination location or the shape required (eg. round or rectangle) for the moving media may be a constraint.

    In order to solve this problem the removable media management system has to manage multiple slots in storage locations for a volume and multiple volumes for a slot. Furthermore, it is necessary to keep the number of required slots in a storage location at a minimum due to cost reasons and the assignment of volumes to slots needs to be in sequence to ease the handling of moving tape volumes.

    The proposed algorithm is a simple and easy to implement solution for this problem and allows to make as many moves as possible considering any number of locations.

The objectives for the algorithm are: keep required number of slots at a storage location to a minimum assign media's to free slots in ascending order any empty slot numbers in a storage location must be higher than the highest slot number assigned in the last inventory management run achieve the objectives fro...