A disk drive implementation that integrates the controller on the disk drive itself. There are several versions of ATA, all developed by the Small Form Factor (SFF) Committee:

ATA: Known also as IDE, supports one or two hard drives, a 16-bit interface and PIO modes 0, 1 and 2. ATA-2: Supports faster PIO modes (3 and 4) and multiword DMA modes (1 and 2). Also supports logical block addressing (LBA) and block transfers. ATA-2 is marketed as Fast ATA and Enhanced IDE (EIDE). ATA-3: Minor revision to ATA-2. Ultra-ATA: Also called Ultra-DMA, ATA-33, and DMA-33, supports multiword DMA mode 3 running at 33 MBps. ATA/66: Also called Ultra-DMA/66 or UDMA-66. A new version of ATA proposed by Quantum Corporation, and supported by Intel, that doubles ATA's throughput to 66 MBps. ATA/100: Also called Ultra-DMA/100 or UDMA-100. A new version of ATA proposed by Quantum Corporation, and supported by Intel, that doubles ATA's throughput to 100 MBps. ATAPI (AT Attachment Packet Interface) An interface between your computer and attached CD-ROM drives and tape backup drives. Most of today's PC computers use the standard IDE (Integrated Drive Electronics) interface to address hard disk drives. ATAPI provides the additional commands needed for controlling a CD-ROM player or tape backup so that your computer can use the IDE interface and controllers to control these relatively newer device types. ATAPI is part of the Enhanced IDE (EIDE) interface (also known as ATA-2).

This definition is in context to Computer Hardware. See more contextual defintions for ATA - AT Attachment.