Patent ID: 6678752
Filing Date: 2004-01-13
Classification: G06F

Abstract:
A method for processing requests to store data objects in a data storage system having multiple types of storage output media including direct-access storage constituting a first type and removable tape media constituting a second type, the system including a storage queue containing pending requests to store data objects in the system, the method comprising operations of:if the request does not meet prescribed criteria of urgency, selecting the second type of output media; if the request meets the prescribed criteria of urgency, selecting output media type according to the data object's size, comprising: if the data object's size exceeds a prescribed upper amount, selecting the second type of output media; if the data object's size is less than a prescribed lower amount, selecting the first type of output media unless conditions including at least one of the following apply, and under such conditions selecting the second type of output media: storage of the second type is substantially immediately ready to conduct input/output and the queue does not contain any data objects of size larger than lower amount; the first type of output media is being utilized by a predetermined maximum number of concurrent storage requests, the second type of output media includes one or more non-busy tape drives, and the second type of output media is ready to conduct input/output before the first type of output media; if the data object's size is between the first and second prescribed amounts, selecting the second type of output media unless conditions exist including at least one of the following, and under such conditions selecting the first type of output media: storage of the second type does not include any non-busy tape drives; storage of the first type is being utilized by less than the predetermined maximum number of concurrent storage requests, and the queue does not contain any data objects smaller than the lower amount; issuing an output of the selected output media type.