1. A dispersed storage (DS) unit comprises: a processing module; and a plurality of hard drives, wherein the processing module is operable to: receive a plurality of memory access requests regarding a plurality of encoded data slices stored at different addressable locations of a hard drive of the plurality of hard drives; queuing write requests of the plurality of memory access requests in a write queue for the hard drive; queuing read requests of the plurality of memory access requests in a read queue for the hard drive; processing the read requests from the read queue with priority over the write requests from the write queue unless a quantity of write requests exceeds a high threshold and then processing one or more write requests from the write queue with priority over the read requests until the quantity of write requests fails below the high threshold; for a read request of the plurality of memory access requests regarding an encoded data slice of the plurality of encoded data slices: retrieve a portion of the encoded data slices from the hard drive; retrieve other portions of the encoded data slice from other hard drives of the plurality of hard drives, wherein the portions of the encoded data slice include parity data and other encoded data slices that are stored across multiple hard drives of the plurality of hard drives; reconstruct the encoded data slice from at least some of the retrieved portions; and fulfill the read request using the reconstructed encoded data slice.