An enhanced file format to store large quantities of variable-sized data records on a storage medium and to permit efficient access and control over data stored in the enhanced file format. A file format is the structure of a file that defines the way it is stored and laid out on a disk. In a preferred embodiment of the present invention, a file format includes a model directory containing models. Models include element lists comprising element chunks. The element chunks include elements, where elements are variable-sized data records.