Caching jukeboxes combine the low media cost of CD and DVD with the higher performance of magnetic disk drives. We propose and evaluate the combination of aggressive file prefetching based on the a priori affinity among a file’s blocks, with block-level usage tracking and removal. This apparently-inconsistent approach takes into account the usage time constants rather than merely the relative performance of two storage levels: the expected lifetime of a block in the large disk cache is long, rendering the fine-grain usage information much more meaningful than in higher levels of the memory hierarchy. Preliminary measurements carried out on our IntelliJuke prototype, along with comparative simulations, confirm the direct cost-performance benefits of our approach. One side benefit is increased effective mechanical reliability of the jukebox. Finally, this work motivates the support of sparse files on disk and illustrates the benefits of making additional information available to storage systems.