All interface communication is done through command and data transfer; the host (the
PC, through the interface controller) sends commands over the interface to the disk, and
the disk sends data over the interface back to the host. Some interfaces are simpler to
use than others and therefore require less command "talk" over the interface.
This can lead to improved responsiveness in simple setups, such as when there is only one
disk on the interface. The amount of time that the interface, its controller, and the hard
disk, require for processing commands is referred to as command overhead.
This is one factor that influences overall interface performance. For more information
on command overhead and its performance implications, see this page in the discussion of hard disk
performance.
Next: Device Type Support and Software Compatibility
