ATA PIO Mode: Difference between revisions

There is only one wire dedicated to selecting which drive on each bus is active. It is either electrically "high" or "low", which means that there can never be more than two devices operational on any ATA bus. They are called the master and the slave devices, for no particular reason. The terms 'master' and 'slave' have largely been abandoned as they inaccurately portray the master drive as having some kind of superiority over the slave drive, or that the latter is dependent on the master. However, these thermsterms will be used in this document. TheirThe functionality of the master and slave drives is almost completely identical. There is a special IO port bit that allows a driver to select either drive as the target drive for each command byte.