ATA-ATAPI.COM

Information for Developers of Products Using
ATA (PATA, IDE/EIDE), Serial ATA (SATA), ATAPI,
CF and Other ATA Related Interfaces

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This site is a great resource for anyone seeking up-to-date and correct information about the ATA and ATAPI interfaces and some related items. Even if you are not a developer you may find lots of useful information here to help you understand the ATA and ATAPI interfaces and some other related items. For example, see the How It Works (HIW) documents and the low level ATA driver C source code that Hale Landis has placed into the public domain.

This site also contains opinions and comments by Hale Landis concerning the current state the ATA/ATAPI interface and the current status of the various committees that publish ATA/ATAPI standards, specifications and other documents.

See the PATA page if you need a quick tour of how ATA/ATAPI works.

What are ATA and ATAPI?

ATA is the real name for the mass storage device interface that is frequently called IDE or EIDE. IDE and EIDE are mostly used by marketing people who do not know what they are selling or by writers for magazines who do not know what they are writing about.

ATA is short for AT Attachment. The AT part is from the IBM PC/AT (1984). ATAPI is short for ATA Packet Interface. ATAPI allows SCSI devices to be attached to the ATA interface. The original ATAPI specification was called SFF-8020. The SFF-8020 specification is very old and very obsolete - do not use it - instead use the ATA/ATAPI-5 or -6 (avoid ATA/ATAPI-7) and the SCSI MMC-4 or -5 standards for the current description of ATAPI. The ATA-8 standard should be done later in 2008. See the History page for the full story.

Some definitions:

Parallel ATA (PATA/PATAPI)

PATA and PATAPI is the traditional ATA interface that has been standardized for 10+ years by the ANSI/INCITS ATA-1 through ATA/ATAPI-7 standards. This interface is widely used by PATA disk drives and PATAPI CD/DVD and tape drives. PCMCIA PC Card ATA devices and Compact Flash (CF) devices use a PATA based interface.

Read more about PATA on the PATA page.

Serial ATA (SATA/SATAPI)

SATA is a serial interface that tries to emulate PATA. SATA is slowing replacing PATA in all applications - both disk drives and ATAPI devices such as CD, DVD and tape.

One of the early problems with SATA was the conflicting standards and incompatibilities between SATA and traditional PATA. And early SATA host controllers and devices had some serious problems with reliability and data integrity.

Read more about SATA on the SATA page.

Current Status of ATA/ATAPI

The ATA/ATAPI-6 standard is the last of the PATA interface standards that you should use. There is an ATA/ATAPI-7 standard that attempts to describe both PATA and SATA. ATA/ATAPI-7 is the result of the merger of an early (incomplete?) SATA specification into the traditional ATA (PATA) standards. ATA/ATAPI-7 can be a confusing mess. One of the problems with SATA is that there are multiple SATA standards and specifications - ATA/ATAPI-7 and the Serial ATA specifications. Read more about this on the SATA page.

Since about 1990 ATA/ATAPI has been the most popular storage device interface. Approximately 90 percent of disk drives manufactured every year use the ATA interface (PATA and SATA). The remainder are various types of SCSI inteface drives. In 2008, it looks like 80+% of disk drives will use a SATA interface. Most CD and DVD devices are ATAPI using the PATA interface. By 2009 most ATAPI devices will probably also use a SATA interface. Most PCMCIA and CF mass storage devices are also ATA or ATAPI devices - these use the PCMCIA PC Card ATA interface that is based on PATA.

ANSI INCITS T13

T13 is the standards committee that develops and maintains the ATA and ATA/ATAPI standards. Visit the T13 web site for the latest information on meeting schedules, proposals for the next version of ATA/ATAPI and copies of the draft standards to review. ... WAIT ... HOWEVER ... There is only one problem with this description of T13... T13 is no longer in control of the ATA interface standard (especially the SATA part). On the surface T13 appears to operate in the public domain and appears to be developing 'open' standards (the purpose of ANSI standards committees). But in reality T13 is used as the public proxy for the private and secret Serial ATA (or Serial I/O or SATA-IO) committee. T13 is prohibited from discussing certain parts of the ATA (especially the SATA part) interface without prior approval from the SATA 'secret society'. If the members of the SATA secret society do not want something discussed at T13 (in the public eye and ear) they can prohibit it. This is possible because the 'major' members of T13 are also members of the SATA 'secret society' and these people (and their employers) exercise control over the T13 agenda and discussions. The SATA secret society does not publish minutes of it meetings so it is not possible to see who attended the meetings, or what was discussed at the meetings, or who voted for and against proposals. But the actions of the SATA secret society directly control how T13 operates. This is a big mess.

There are many versions of ATA/ATAPI...

Here are links to the major organizations that publish ATA information:

If you are working with PATA or PATAPI then you need the ATA/ATAPI-6 document found at www.t13.org.

If you are working with CD or DVD devices (PATAPI or SATAPI) then you also need the SCSI Multi Media Commands (MMC) document. Do not confuse the SCSI MultiMedia Commands (MMC) document with the Multi Media Card (MMC) specification (see below). The SCSI MMC document can be found at www.t10.org.

If you are working with SATA then you must determine which of the SATA documents you will use - the ATA/ATAPI-7 version or the ATA-8 version or the SATA secret society version. See www.t13.org or www.sata-io.org.

If you are working with PCMCIA PC Card ATA or Compact Flash (CF) then you need the PCMCIA documents found at www.pcmcia.org. For CF you also need the CF specification found at www.compactflash.org. Both PCMCIA PC Card ATA and CF devices are really PATA based devices so you also need the ATA/ATAPI-6 document from www.t13.org.

CE-ATA is a variation of the MMC/SD (Multi Media Card / Secure Digital) interface. This interface is defined by the very private and very secretive Multi Media Card Association and the SD Card Association. Virtually no information about MMC/SD can be obtained unless you are a member of these associations. See www.mmca.org. and www.sdcard.org. The odd thing is that the CE-ATA specification is available to the public but it may not be of much value without the MMC and SD specifications. The CE-ATA specification can be found at www.ce-ata.org. Note that the CE-ATA committee was created by some of the same companies that formed the SATA secret society. Little is know about how the CE-ATA specification was developed. At about the same time that the CE-ATA specification was created in 2005 the MMC created an 'ATA on MMC' specification.

More Info... ???

The Berg Software Design web site is a great resouce for finding information, products and services for all I/O interfaces.

If you need serious ATA design or development help for your ATA/ATAPI project, contact Deadline Specialists.

Other information at this site:


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Page updated 06 Mar 2012.