A disk drive capable of supporting speculative data transfers. Requested first data are read from the disk drive. Before the first data are read, a determination is made as to whether there are un-requested second data that are likely to be requested at a later time as part of a data stream. If so, then a determination is made as to whether the second data and the first data are stored in locations that are physically/logically proximate on the same disk. If the second data are close to the first data, then the second data are speculatively read and stored in a local disk cache. If a subsequent request comes to the disk drive for the second data, then the second data are quickly produced from the disk cache rather than being slowly read off the disk.