Patent ID: 6061732
Filing Date: 2000-05-09
Classification: G06F,H04N

Abstract:
A system for retrieving blocks of data, such as audio and/or video data, from a storage medium and supplying the blocks in the form of a plurality of data streams to users; the storage medium including a plurality of record-carrier based storage units; the block including at least one data unit, where a data unit is stored on one of the storage units; the system comprising:reader means, for each of the storage units, for servicing a batch of carrier access requests by reading a corresponding batch of data units in a single relative movement of a reading head of the storage unit with respect to the record-carrier of the storage unit; each unit of the batch of data units being associated with one of the carrier access requests of the batch of carrier access requests; andscheduler means for controlling reading of data blocks for the data streams from the storage units by:determining for at least one data unit of each block in which storage unit the data unit is stored and placing a carrier access request in a read queue; the carrier access request being associated with the data unit and the determined storage unit; andcyclically extracting for each of the plurality of storage units a batch of carrier access requests associated with the storage unit from the read queue in an asynchronous manner, by for each individual storage unit, issuing a batch of carrier access requests for the storage unit to the reader in response to the reader having substantially completed reading data units for a previous batch of carrier access requests for the storage unit; andissuing the batches to the reader.