This is the second ATA/ATAPI standard. Released in 1996.
This standard extends the AT Attachment Interface with the addition of new commands, and defines improved interface transfer rates. In addition, general improvements have been made in content for completeness and to improve clarity.
This standard defines the AT Attachment Interface and integrated interfaces between devices and host processors. It provides a common point of attachment for systems manufacturers, system integrators, and suppliers of intelligent devices.
The application environment for the AT Attachment Interface is any device which uses internal storage.
The PC AT Bus(TM) is a widely used and implemented interface for which a variety of devices have been manufactured. As a means of reducing size and cost, a class of products has emerged which embed the controller functionality in the device. Because of their compatibility with existing AT hardware and software this interface quickly became a de facto industry standard. While the AT Attachment Interface has its roots in the PC AT Bus(TM), its use has extended to many other systems.
Note: there is no practical use of this document. This is a history now.
Download: d0948r4c — ATA/ATAPI-2 (PDF)