A data storage system includes a mass storage unit storing a data entity, such as a digital representation of a video presentation, that is partitioned into a plurality N of temporally-ordered segments. A data buffer is bidirectionally coupled to the mass storage unit for storing up to M of the temporally-ordered segments, wherein M is less than N. The data buffer has an output for outputting stored ones of the temporally-ordered segments. The data storage system further includes a data buffer manager for scheduling transfers of individual ones of the temporally-ordered segments between the mass storage unit and the data buffer. The data buffer manager schedules the transfers in accordance with at least a predicted time that an individual one of the temporally-ordered segments will be required to be output from the data buffer. When employed with a media streamer (10) distributed data buffer management techniques are employed for selecting blocks to be retained in a buffer memory, either in a storage node (16, 17) or in a communication node (14). These techniques rely on the predictable nature of the video data stream, and thus are enabled to predict the future requirements for a given one of the data blocks.