This is the fifth ATA/ATAPI standard. Released in 2000.

This standard specifies the AT Attachment Interface between host systems and storage devices. It provides a common attachment interface for systems manufacturers, system integrators, software suppliers, and suppliers of intelligent storage devices.

The application environment for the AT Attachment Interface is any host system that has storage devices contained within the processor enclosure.

This standard defines the connectors and cables for physical interconnection between host and storage device, as well as, the electrical and logical characteristics of the interconnecting signals. It also defines the operational registers within the storage device, and the commands and protocols for the operation of the storage device.

This standard maintains a high degree of compatibility with the AT Attachment with Packet Interface Extensions standard (ATA/ATAPI-4), NCITS 317-1998, and while providing additional functions, is not intended to require changes to presently installed devices or existing software.