Today, the ATA interfaces are the most commonly used interface on IBM compatible computers to connect to computer hard disk drives, CD-ROM drives, and other types of disk drives. Each of the below standards are compatible with each other, which means a new ATA drive can be used in a computer using an older ATA specification. Finally, when a new feature was introduced in an ATA standard, that feature is also found in future releases. In other words, a ATA-4 is going to have support for PIO modes 0, 1, 2, 3, and 4, even though these were introduced in ATA-1 and ATA-2.
Below is a listing of each of the ATA, IDE, and EIDE standards to help give user a better understanding of the history behind this interface as well as an understanding of each interface's capabilities.
ATA / ATA-1 / IDE
ATA is short for AT Attachment interface and also more commonly known as IDE or ATA-1. ATA was approved as a standard on May 12, 1994 under the ANSI document number X3.221-1994. ATA was first developed by Control Data Corporation, Western Digital, and Compaq. ATA-1 utilizes a 8-bit or 16-bit interface, has a transfer rates of up to 8.3MBps, and has support for PIO modes 0, 1, and 2. Today, ATA / ATA-1 is now considered obsolete.
ATA-2 / EIDE / Fast ATA / Fast IDE / Ultra ATA
ATA-2, more commonly known as EIDE, and sometimes known as Fast ATA or Fast IDE, is a standard approved by ANSI in 1996 under document number X3.279-1996. ATA-2 introduces new PIO modes of 3 and 4, has a transfer rate of up to 16.6MBps, DMA modes 1 and 2, LBA support, and supports drives up to 8.4GB. Today, ATA-2 is now considered obsolete.
ATA-3 / EIDE
ATA-3 is a standard approved by ANSI in 1997 under document number X3.298-1997. ATA-3 added additional security features and the new S.M.A.R.T feature.
ATA-4 / ATAPI-4 / ATA/ATAPI-4
ATA-4 is a standard approved by ANSI in 1998 under document NCITS 317-1998. ATA-4 includes the ATAPI packet command feature, introduces UDMA/33, also known as ultra-DMA/33 or ultra-ATA/33, which is capable of supporting data transfer rates of up to 33MBps.
ATA-5 / ATA/ATAPI-5
ATA-5 is a standard approved by ANSI in 2000 under document NCITS 340-2000. ATA-5 adds support for Ultra-DMA/66, which is capable of supporting data transfer rates of up to 66MBps, and has the capability of detecting between 40 or 80-wire cables.
ATA-6 / ATA/ATAPI-6
ATA-6 is a standard approved by ANSI in 2001 under document NCITS 347-2001. ATA-6 added support for Ultra-DMA/100, and had a transfer rate of up to 100MBps.
ATA layout
Each of the above ATA interfaces that are used with the 3.5-inch disk drives have a 40-pin connector and are capable of supporting up to two drives per interface. However, 2.5-inch hard disk drives utilize a 50-pin connector and PCMCIA utilizes a 68-pin connector Below is an illustration of the ATA interface
Pin Function Pin Function
1 Reset 2 Ground
3 Data 7 4 Data 8
5 Data 6 6 Data 9
7 Data 5 8 Data 10
9 Data 4 10 Data 11
11 Data 3 12 Data 12
13 Data 2 14 Data 13
15 Data 1 16 Data 14
17 Data 0 18 Data 15
19 Ground 20 Key
21 DDRQ 22 Ground
23 I/O Write 24 Ground
25 I/O Read 26 Ground
27 IOC HRDY 28 Cable Select
29 DDACK 30 Ground
31 IRQ 32 No Connect
33 Addr 1 34 GPIO_DMA66_Detect
35 Addr 0 36 Addr 2
37 Chip Select 1P 38 Chip Select 3P
39 Activity 40 Ground
Related dictionary definitions
For additional information, please see each of the below dictionary definitions for a brief definition as well as related links and terms.
ATA definition
IDE definition
EIDE definition
Other hard disk drive definitions
Other CD definitions
ATAPI
Short for AT Attachment Packet Interface, ATAPI is an extension to ATA which allows support for devices such as CD-ROM drives, Tape drives and other computer peripherals and not just hard disk drives. Before the release of ATA-4 or ATA/ATAPI-4, ATAPI was a separate standard from ATA.
Related dictionary definitions
For additional information, please see each of the below dictionary definitions for a brief definition as well as related links and terms.
ATAPI definition
Other hard disk drive definitions
Other CD definitions
SERIAL ATA (SATA)
Shot for SerialATA, SATA 1.0 was first released in August 2001 and is a replacement for the Parallel ATA interface used in IBM compatible computers. SerialATA is capable of delivering 1.5Gbps (150MBps) of performance to each drive within a disk array, offers backwards compatibility for existing ATA and ATAPI devices, and offers a thin small cable solution as seen in the below picture. This cable helps make a much easier cable routing and offers better airflow in the computer when compared to the earlier ribbon cables used with ATA drives.
