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IDE ATA/Atapi Controllers History

I just got an idea to put this on the site, as I had a small discussion with one of my friend yesterday, although it’s not an interesting topic to all, but some techno savvy might find it really useful. 

ATA interface was developed in 1986 by 3 companies 

1. CDC (Control Data Corporation), also called Imprimis-A disk drive company

2. Western Digital-Major silicon company and

3. Compaq Computers

Initially this new interface was called IDE or ATA and being used by Compaq. Soon all major disk drive companies started making ATA/IDE drives. Today’s SCSI CAM standard developed by The Common Access Committee states the beginning and development of the interface. 

Let’s look at some major turn around thereafter. After few years in 1989 Seagate purchased Imprimis from CDC and in 1995 the same firm also purchased the Conner Peripherals. By the mid 1990s Western Digital had become a major disk drive supplier.ATA was originally designed for and worked only with hard disks and devices that could emulate them. The introduction of ATAPI (ATA Packet Interface) by a group called the Small Form Factor committee allowed ATA to be used for a variety of other devices that require functions beyond those necessary for hard disks. For example, any removable media device needs a “media eject” command, and a way for the host to determine whether the media is present, and these were not provided in the ATA protocol.The Small Form Factor committee approached this problem by defining ATAPI, the “ATA Packet Interface”. ATAPI is actually a protocol allowing the ATA interface to carry SCSI commands and responses; therefore all ATAPI devices are actually “speaking SCSI” other than at the electrical interface. In fact, some early ATAPI devices were simply SCSI devices with an ATA/ATAPI to SCSI protocol converter added on. The SCSI commands and responses are embedded in “packets” (hence “ATA Packet Interface”) for transmission on the ATA cable. This allows any device class for which a SCSI command set has been defined to be interfaced via ATA/ATAPI.ATAPI devices are also “speaking ATA”, as the ATA physical interface and protocol are still being used to send the packets. On the other hand, ATA hard drives and solid state drives do not use ATAPI.ATAPI devices include CD-ROM and DVD ROM drives, tape drives and large-capacity floppy drives such as the zip drive and Super Disk drive. Removable media devices other than CD and DVD drives are classified as ARMD (ATAPI Removable Media Device) and can appear as either a super-floppy (non-partitioned media) or a hard drive (partitioned media) to the operating system. The SCSI commands and responses used by each class of ATAPI device (CD-ROM, tape, etc.) are described in other documents or specifications specific to those device classes and are not within ATA/ATAPI or the T13 committee’s purview.

Various Standards of ATA/ATAPI 

ATA (also called ATA-1), ATA-2, ATA-3 and ATA/ATAPI-4, ATA/ATAPI-5, ATA/ATAPI-6 and ATA/ATAPI- 7 and then ATA-8 

ATA-1 and ATA-2 

ATA is the real standard for what is widely known as IDE. ATA-2 is the real standard for what is widely known as EIDE. Other names are just names used by different marketing companies. 

IDE was used by Conner Peripherals, Compaq and Western Digital starting back in 1986-1987. It continues to be widely used as the alternate name for ATA. 

EIDE was first used by Western Digital to hype a new line of disk drives back in 1993 or 1994. These were ATA-2 compatible drives that supported the new PIO modes 3 and 4 data transfer timings. Western Digital was trying to establish itself as a major disk drive supplier in those days. Western Digital continues to use EIDE to describe their products even though the ATA interface has progressed well beyond the capabilities of ATA-2. Western Digital just keeps redefining what they mean by EIDE! 

FASTATA and FASTATA-2 were used by Seagate and Quantum in marketing programs that were intended to counter the Western Digital EIDE marketing hype back in 1993 or 1994. It appears that by 1998 both Seagate and Quantum had stopped using these alternative names for ATA products. 

In 1999 some companies started to use ULTRA ATA to describe products that support the ATA/ATAPI-4 Ultra DMA 33 data transfer protocols. We will have to wait and see what cute name the disk drive marketing folks come up with to sell ATA/ATAPI-5’s Ultra DMA 66 data transfer protocols.  

These are all just alternative names for ATA used mostly by marketing departments to make it sound like they have a REALLY NEW AND IMPROVED product that is somehow different from the competition’s product. 

ATA-3 

ATA-3 introduces some new features of questionable value: SMART and Security. Note that ATA-3 does NOT introduce any new (faster) PIO or DMA data transfer modes (there is no such thing as PIO mode 5!). 

ATA/ATAPI-4 

The ATAPI command and reset protocols are new. Many old ATA commands and features are now obsolete, such as the Format Track and Read/Write Long commands. There is a new data transfer protocol named Ultra DMA that adds data integrity (via a CRC check) and much higher data transfer rates (up to 33MB/second). There is a command overlapping and command queuing protocol for ATA and ATAPI devices.  

ATA/ATAPI-5 

ATA/ATAPI-5 deletes a few old commands, adds a few new commands, changes the way a few commands operate. But the big thing in ATA/ATAPI-5 are the two new and faster Ultra DMA 66 data transfer modes.  

ATA/ATAPI-6 

ATA/ATAPI-6 includes another even faster Ultra DMA mode 5, also known as Ultra DMA 100. It also includes a method of increasing the number of LBA bits from 28 to 48 and increasing the Sector Count from 8 bits to 16 bits.  

ATA/ATAPI-7 

ATA/ATAPI-7 includes UltraDMA mode 6 also known as Ultra DMA 133, some new commands for use by digital video recorders, and the T13 version of Serial ATA (SATA). The ATA/ATAPI-7 document has been split into three volumes: one for the hard disk commands, one for the traditional parallel ATA interface and one for the SATA-1 interface. Unless you need documentation for a specific ATA/ATAPI-7 feature, avoid using ATA/ATAPI-7 - use ATA/ATAPI-6 or use ATA-8.  ATA-8 Featuring non-volatile cache to speed up critical OS files