Michael J. Mahon wrote:
Any "smart" drive will wind up reading the disk data into an internal buffer and then transferring the data to the host computer when requested. This double move performed by a single processor guarantees that a smart drive cannot move data at the rate the disk can support.
Just to go entirely off-topic, this isn't quite right as the Commodore PET/CBM drives had two 6502s in interleaved operation, one for talking to the host computer and one for talking to the actual drive hardware. Those drives were reasonably fast though expensive. But then when they ported their DOS code to a single-CPU design for the cheaper home computer line they kept this logic around (one CPU now alternately impersonating the two CPUs of the old design), which made the DOS really weird (the two "personalities" didn't simply call each other as needed but rather communicated via command lists in RAM) and contributed to its slowness. -- Linards Ticmanis