This standard specifies the AT Attachment Interface between host systems and storage devices. It provides acommon attachment interface for systems manufacturers, system integrators, software suppliers, andsuppliers of intelligent storage devices.The application environment for the AT Attachment Interface is any host system that has storage devicescontained within the processor enclosure.This standard defines the connectors and cables for physical interconnection between host and storagedevice, as well as, the electrical and logical characteristics of the interconnecting signals. It also defines theoperational registers within the storage device, and the commands and protocols for the operation of thestorage device.This standard maintains a high degree of compatibility with the AT Attachment-3 Interface standard (ATA-3),X3.298-1997, and while providing additional functions, is not intended to require changes to presentlyinstalled devices or existing software.