An apparatus includes a storage medium, an arm for positioning a recording head adjacent to the storage medium, and a controller for receiving objects and for selecting blocks on the storage medium to be written by the recording head based on information in the objects. A method for storing objects is also provided. In another aspect, the invention provides a method for writing data in data storage devices. The method includes: receiving access commands for objects, selecting blocks on a storage medium to be written by a recording head based on information in the objects, and writing data from the objects to the selected blocks.