Abstract: An interface allows a given CPU (Central Processing Unit) to communicate concurrently with a large number of disk drives in a high-performance, low-cost system. Plural seek operations can be performed concurrently, to serve a common processor. Also, heterogeneous physical drives--of any physical or logical configuration (storage capacity, number of heads, and so forth)--can be combined into one or more "logical" drives as seen by a host operating system. An "on-board" embodiment provides an "enhanced" IDE (Integrated Drive Electronics) disk drive that is an extension of the industry-standard IDE drives, allowing an arbitrary number of independently seeking IDE drives on a conventionally single-seeking, two-drive-maximum bus. In a "paddle board" embodiment, low-cost IDE drives of arbitrary physical size, storage capacity and geometry, can be combined simply and inexpensively into a high-performance storage device. For example, a 3.5"80 MB (megabyte) drive can be transparently combined with a 2.5" 60 MB drive.