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{{Redirect|SATA}}
{{Infobox Computer Hardware Bus
| name = SATA
| fullname = Serial ATA
| image = SATA ports.jpg
| caption = First-generation (1.5&nbsp;Gbit/s) SATA ports on a [[motherboard]]
| invent-date = 2003
| replaces = [[Parallel ATA]] (PATA)
| speed = 1.5, 3.0, 6.0&nbsp;Gbit/s
| style = s
| hotplug = Yes<ref name=linux-ata/>
| external = Yes ([[#eSATA|eSATA]])
}}

'''Serial ATA''' ('''SATA''' or '''Serial Advanced Technology Attachment''') is a [[computer bus]] interface for connecting [[host adapter|host bus adapters]] to [[mass storage device]]s such as [[hard disk drive]]s and [[optical drive]]s. Serial ATA was designed to replace the older [[AT Attachment|ATA (AT Attachment)]] standard (also known as EIDE). It is able to use the same low level commands, but serial ATA host-adapters and devices communicate via a high-speed [[serial communications|serial]] cable over two pairs of conductors. In contrast, the parallel ATA (the [[retronym|redesignation]] for the legacy ATA specifications) used 16 data conductors each operating at a much lower speed.

SATA offers several advantages over the older [[parallel ATA]] (PATA) interface: reduced cable-bulk and cost (reduced from 80 wires to seven), faster and more efficient [[data transfer]], and [[hot swapping]].

The SATA host adapter is integrated into almost all modern consumer laptop [[computer]]s and desktop [[motherboard]]s. {{As of|2009}}, SATA has replaced parallel ATA in most shipping consumer PCs. PATA remains in industrial and embedded applications dependent on [[CompactFlash]] storage although the new [[CompactFlash#CFast|CFast]] storage standard will be based on SATA.<ref>{{cite web|url=http://www.engadget.com/2008/02/25/cfast-compactflash-cards-now-said-to-be-coming-in-18-to-24-mont/|author=Donald Melanson|pubdate=20080225|publisher=[[Engadget]]|title=CFast CompactFlash cards now said to be coming in "18 to 24 months"|date=25 February 2008|accessdate=19 March 2009}}</ref><ref>{{cite web|url=http://www.dpreview.com/news/0901/09010902preteccfaststoragecards.asp|publisher=[[DPReview]]|title=Pretec release CFast card with SATA interface|date=8 January 2009|accessdate=19 March 2009}}</ref>

== SATA specification bodies ==
Serial ATA industry compatibility specifications originate from The Serial ATA International Organization (aka. SATA-IO, serialata.org). The SATA-IO group collaboratively creates, reviews, ratifies, and publishes the interoperability specifications, the test cases, and plug-fests. As with many other industry compatibility standards, the SATA content ownership is transferred to other industry bodies: primarily the [[INCITS]] [[T13 subcommittee|T13]]subcommittee ATA, the INCITS [[T10 subcommittee|T10]] subcommittee ([[SCSI]]); a subgroup of T10 responsible for [[Serial Attached SCSI|SAS]]. The complete specification from SATA-IO.<ref>{{cite web|url=http://www.ata-atapi.com/sata.html|title=ATA-ATAPI.COM Serial ATA (SATA)|accessdate=29 January 2009}}</ref> The remainder of this article will try to use the terminology and specifications of SATA-IO.

The SATA-IO succeeded in its mission of improving PATA.
More than 1.1 billion SATA disk drives have been shipped from 2001 through 2008.{{Clarify|reason=the 'Year Created' field, above, says 2003 but this says it has been shipping since 2001|date=August 2010}}
SATA’s market share in the desktop PC market is 99% in 2008.
http://www.serialata.org/documents/SATA-Rev-30-Presentation.pdf

== Features ==
=== Hotplug ===
The Serial ATA Spec, includes logic for SATA device [[hotplug]]ging. Devices and motherboards that meet the interoperability spec are capable of hot plugging.

=== Advanced Host Controller Interface ===
As their standard interface, SATA controllers use the [[Advanced Host Controller Interface|AHCI (Advanced Host Controller Interface)]], allowing advanced features of SATA such as [[hotplug]] and [[native command queuing]] (NCQ). If AHCI is not enabled by the motherboard and chipset, SATA controllers typically operate in "IDE emulation" mode, which does not allow features of devices to be accessed if the ATA/IDE standard does not support them.

Windows device drivers that are labeled as SATA are often running in IDE emulation mode unless they explicitly state that they are AHCI mode, in [[RAID]] mode, or a mode provided by a proprietary driver and command set that was designed to allow access to SATA's advanced features before AHCI became popular. Modern versions of [[Microsoft Windows]], [[FreeBSD]], [[Linux kernel|Linux]] with version 2.6.19 onward,<ref>{{cite web|url=http://linux-ata.org/driver-status.html#ahci |title=Serial ATA (SATA) Linux hardware/driver status report |publisher=Linux-ata.org |date= |accessdate=2010-01-26}}</ref> as well as [[Solaris (operating system)|Solaris]] and [[OpenSolaris]] include support for AHCI, but older OSes such as [[Windows XP]] do not. Even in those instances a proprietary driver may have been created for a specific chipset, such as [[Intel]]'s.<ref>http://www.intel.com/support/chipsets/imst/sb/CS-020825.htm</ref>

== Revisions ==
=== SATA Revision 1.0 (SATA 1.5 Gbit/s) ===

First-generation SATA interfaces, now known as SATA 1.5 Gbit/s, communicate at a rate of 1.5&nbsp;Gbit/s. Taking [[8b/10b encoding]] overhead into account, they have an actual uncoded transfer rate of 1.2&nbsp;Gbit/s (1500000000*8/10/1024/1024/8 ≅ 143.05&nbsp;MiB/s). The theoretical burst throughput of SATA 1.5 Gbit/s is similar to that of [[AT Attachment|PATA]]/133, but newer SATA devices offer enhancements such as NCQ, which improve performance in a multitasking environment.

During the initial period after SATA 1.5 Gbit/s finalization, adapter and drive manufacturers used a "bridge chip" to convert existing PATA designs for use with the SATA interface.{{Citation needed|date=July 2007}} Bridged drives have a SATA connector, may include either or both kinds of power connectors, and, in general, perform identically to their PATA equivalents. Most lack support for some SATA-specific features such as NCQ. Native SATA products quickly eclipsed bridged products with the introduction of the second generation of SATA drives.{{Citation needed|date=July 2007}}

As of April 2010 mechanical [[hard disk drive]]s can transfer data at up to 157&nbsp;MB/s,<ref name="Tom2010HardDrives">{{cite news |title=VelociRaptor Returns: 6Gb/s, 600GB, And 10,000 RPM |publisher=tomshardware.com |author=Patrick Schmid and Achim Roos |url=http://www.tomshardware.com/reviews/wd6000hlhx-velociraptor-600gb,2600-5.html |date=2010-04-06 |accessdate=2010-06-26}}</ref> which is beyond the capabilities of the older PATA/133 specification and also exceeds a SATA 1.5 Gbit/s link. High-performance [[Solid-state drive|flash drives]] can transfer data at up to 308&nbsp;MB/s which exceeds a SATA 3 Gbit/s link.<ref name="Tom2010SolidStateDrives">{{cite news |title=Spring 2010 Solid State Drive Roundup, Part 2 |publisher=tomshardware.com |author=Patrick Schmid and Achim Roos |url=http://www.tomshardware.com/reviews/6gb-s-ssd-hdd,2603-7.html |date=2010-04-13 |accessdate=2010-06-26}}</ref>

=== SATA Revision 2.0 (SATA 3 Gb/s) ===

Second generation SATA interfaces running at 3.0&nbsp;Gbit/s are shipping in high volume {{as of|2010|lc=on}}, and prevalent in all{{Citation needed|date=September 2010}} SATA disk drives and the majority of PC and server chipsets. With a native transfer rate of 3.0 Gbit/s, and taking [[8b/10b encoding]] into account, the maximum uncoded transfer rate is 2.4&nbsp;Gbit/s (286&nbsp;MiB/s). The theoretical burst throughput of SATA 3.0 Gbit/s is roughly double that of [[AT Attachment|PATA]]/133. In addition, SATA devices offer enhancements such as NCQ that improve performance in a multitasking environment.

All SATA data cables meeting the SATA spec are rated for 3.0&nbsp;Gbit/s and will handle current mechanical drives without any loss of sustained and burst data transfer performance. However, high-performance flash drives are approaching SATA 3 Gbit/s transfer rate, and this is being addressed with the SATA 6 Gb/s interoperability standard.

=== SATA Revision 3.0 (SATA 6 Gb/s) ===

[[Serial ATA International Organization]] presented the draft specification of SATA 6 Gbit/s physical layer in July 2008,<ref>{{cite press release
| url = http://www.sata-io.org/documents/SATA_6gbphy_pressrls_finalrv2.pdf | format = PDF
| date = 18 August 2008 | publisher = SATA-IO
| title = New SATA Spec Will Double Data Transfer Rates to 6&nbsp;Gbit/s
| accessdate = 13 July 2009
}}</ref>
and ratified its physical layer specification on August 18, 2008.<ref>{{cite web|url=http://www.sata-io.org/technology/6Gbdetails.asp|publisher=[[SATA-IO]]|title=SATA Revision 3.0 |date=27 May 2009|accessdate=4 December 2009}}</ref> The full 3.0 standard (peak throughput about 600&nbsp;MB/s (10b/8b coding plus 8 bit to one byte, without the protocol, or encoding overhead) was released on May 27, 2009.<ref>{{cite press release|url=http://www.sata-io.org/documents/SATA-Revision-3.0-Press-Release-FINAL-052609.pdf |title=SATA-IO Releases SATA Revision 3.0 Specification |publisher=Serial ATA International Organization |date=May 27, 2009 |accessdate=3 July 2009}}</ref> While even the fastest conventional hard disk drives can barely saturate the original SATA 1.5 Gbit/s bandwidth, Solid-State Drives have already saturated the SATA 3 Gbit/s limit at 250&nbsp;MB/s net read speed. Ten channels of fast flash can reach well over 500&nbsp;MB/s with new [[Open NAND Flash Interface Working Group|ONFI]] drives, so a move from SATA 3 Gbit/s to SATA 6 Gbit/s would benefit the flash read speeds. As for the standard hard disks, the reads from their built-in [[disk buffer|DRAM cache]] will end up faster across the new interface.<ref>{{cite web|url=http://www.theinquirer.net/inquirer/news/1023995/idf-2008-sata-doubles-speed |title=IDF Fall 2008 coverage |publisher=The Inquirer |date= |accessdate=2010-01-26}}</ref>
SATA 6 Gbit/s hard drives and Motherboards are now shipping from several suppliers.

The new specification contains the following changes:
* 6 Gb/s for scalable performance when used with SSDs
* Continued compatibility with [[Serial attached SCSI|SAS]], including SAS 6 Gb/s. "A SAS domain may support attachment to and control of unmodified SATA devices connected directly into the SAS domain using the Serial ATA Tunneled Protocol (STP)" from the SATA_Revision_3_0_Gold specification.
* Isochronous Streaming command [[Native Command Queuing]] (NCQ) streaming command to enable [[isochronous]] quality of service data transfers for streaming digital content applications.
* An NCQ Management feature that helps optimize performance by enabling host processing and management of outstanding NCQ commands.
* Improved power management capabilities.
* A small [[low insertion force]] (LIF) connector for more compact 1.8-inch storage devices.
* A connector designed to accommodate 7&nbsp;mm optical disk drives for thinner and lighter notebooks.
* Alignment with the [[INCITS]] ATA8-ACS standard.

In general, the enhancements are aimed at improving quality of service for [[video streaming]] and high-priority interrupts. In addition, the standard continues to support distances up to a [[meter]]. The new speeds may require higher power consumption for supporting chips, factors that new process technologies and power management techniques are expected to mitigate. The new specification can use existing SATA cables and connectors, although some [[Original equipment manufacturer|OEM]]s are expected to upgrade host connectors for the higher speeds.<ref>{{cite web|url=http://www.eetimes.com/news/latest/showArticle.jhtml;jsessionid=BPV3PTKDT0FC2QSNDLSCKHA?articleID=210101445 |title=EETimes news report |publisher=Eetimes.com |date= |accessdate=2010-01-26}}</ref>
Also, the new standard is backwards compatible with SATA 3 Gbit/s.<ref name="SATA-IO website">{{cite web|url=http://www.sata-io.org/developers/naming_guidelines.asp |title=SATA-IO Specifications and Naming Conventions |publisher=Sata-io.org |date= |accessdate=2010-01-26}}</ref>

=== eSATA ===
[[File:Port-compare-esatap.jpg|thumb|An [[eSATAp]] port (left) and an [[eSATA]] port (right) ]]
[[Image:ESATA Logo.svg|right|thumb|The official eSATA logo]]

Standardized in 2004, eSATA (e=external) provides a variant of SATA meant for external connectivity. It has revised electrical requirements in addition to incompatible cables and connectors:

* Minimum transmit potential increased: Range is 500–600&nbsp;mV instead of 400–600&nbsp;mV.
* Minimum receive potential decreased: Range is 240–600&nbsp;mV instead of 325–600&nbsp;mV.
* Identical protocol and logical signaling (link/transport-layer and above), allowing native SATA devices to be deployed in external enclosures with minimal modification
* Maximum cable length of {{convert|2|m|ft}} ([[USB]] and [[FireWire]] allow longer distances.)
* The external cable connector equates to a shielded version of the connector specified in SATA 1.0a with these basic differences:
** The external connector has no "L"-shaped key, and the guide features are vertically offset and reduced in size. This prevents the use of unshielded internal cables in external applications and vice-versa.
** To prevent [[Electrostatic discharge|ESD]] damage, the design increased insertion depth from 5&nbsp;mm to 6.6&nbsp;mm and the contacts are mounted farther back in both the receptacle and plug.
** To provide [[Electromagnetic interference|EMI]] protection and meet FCC and CE emission requirements, the cable has an extra layer of shielding, and the connectors have metal contact-points.
** The connector shield has springs as retention features built in on both the top and bottom surfaces.
** The external connector and cable have a design-life of over five thousand insertions and removals, whereas the internal connector is specified to withstand only fifty.

[[Image:SATA2 und eSATA-Stecker.jpg|thumb|right|SATA (left) and eSATA (right) connectors]]

Aimed at the consumer market, eSATA enters an external storage market already served by the USB and FireWire interfaces. Most external hard-disk-drive cases with FireWire or USB interfaces use either PATA or SATA drives and "bridges" to translate between the drives' interfaces and the enclosures' external ports, and this bridging incurs some inefficiency. Some single disks can transfer 157&nbsp;MB/s during real use,<ref name="Tom2010HardDrives"/> about four times the maximum transfer rate of USB 2.0 or [[IEEE 1394a|FireWire 400 (IEEE 1394a)]] and almost twice as fast as the maximum transfer rate of FireWire 800, though the S3200 [[FireWire]] 1394b spec reaches ~400&nbsp;MB/s (3.2&nbsp;Gbit/s). Finally, some low-level drive features, such as [[S.M.A.R.T.]], may not operate through some USB [http://sourceforge.net/apps/trac/smartmontools/wiki/USB] or FireWire or USB+FireWire bridges. eSATA does not suffer from these issues provided that the controller manufacturer (and its drivers) presents eSATA drives as ATA devices, rather than as "SCSI" devices (as has been common with Silicon Image, JMicron, and NVIDIA nForce drivers for Windows Vista); In those cases, even SATA drives will not have low-level features accessible. USB 3.0's 4.8&nbsp;Gbit/s and Firewire's future 6.4&nbsp;Gb/s (768&nbsp;MB/s) will be faster than eSATA I, but the eSATA version of SATA 6G will operate at 6.0&nbsp;Gb/s (the term SATA III is being eschewed by the SATA-IO to avoid confusion with SATA II 3.0 Gb/s, which was colloquially referred to as "SATA 3G" [bps] or "SATA 300" [MB/s] since 1.5 Gb/s SATA I and 1.5 Gb/s SATA II were referred to as both "SATA 1.5G" [b/s] or "SATA 150" [MB/s]). Therefore, they will operate at negligible differences of each other <ref>
{{cite web |url=http://www.hddlife.com/eng/faq.html |title=Questions about the indicators of health/performance (in percent) |publisher=HDDlife |accessdate=29 August 2007}}</ref>.

[[Image:Sky HD Box.jpg|thumb|right|[[HDMI]], [[Ethernet]], and eSATA ports on a [[Sky+ HD]] Digibox, which allows for extended external [[digital video recorder|DVR]] storage.]]

eSATA can be differentiated from USB 2.0 and FireWire external storage for several reasons. As of early 2008, the vast majority of mass-market computers have USB ports and many computers and consumer electronic appliances have FireWire ports, but few devices have external SATA connectors. For small form-factor devices (such as external 2.5-inch disks), a PC-hosted USB or FireWire link supplies sufficient power to operate the device. Where a PC-hosted port is concerned, eSATA connectors cannot supply power, and would therefore be more cumbersome to use. Note that this problem has been solved by the introduction of [[eSATAp]].<ref>{{cite web |url=http://www.sata-io.org/documents/External%20SATA%20WP%2011-09.pdf|title=External Serial ATA |publisher=Silicon Image, Inc|accessdate=8 August 2009}}</ref> Some e-sata ports double as [[eSATA/USB]].

Owners of desktop computers that lack a built-in eSATA interface can upgrade them with the installation of an eSATA [[host bus adapter]] (HBA), while notebooks can be upgraded with [[Cardbus]]<ref name="addonics_cardbus">{{cite web|url=http://www.addonics.com/products/host_controller/adcb2sa-e.asp |title=CardBus SATA adapter |publisher=Addonics.com |date= |accessdate=2010-01-26}}</ref> or [[ExpressCard]]<ref name="addonics_expresscard">{{cite web|url=http://www.addonics.com/products/host_controller/adexc34-2e.asp |title=ExpressCard SATA adapter |publisher=Addonics.com |date= |accessdate=2010-01-26}}</ref> versions of an eSATA HBA. With passive adapters, the maximum cable length is reduced to {{convert|1|m|ft}} due to the absence of compliant eSATA signal-levels. Full SATA speed for external disks (115&nbsp;MB/s) have been measured with external RAID enclosures.{{Citation needed|date=July 2007}}

==== eSATAp ====
{{Main|eSATAp}}
[[File:42465-panel.jpg|thumb|1 cable solution. An [[eSATAp]] HDD enclosure from Delock.]]
eSATAp is also known as Power over eSATA or eSATA/USB Combo.
eSATAp port combines the strength of both eSATA(high speed) and USB(compatibility) into a single port. eSATAp devices are now capable of being self powered. On a desktop workstation, eSATAp port can supply 12&nbsp;V to power up a 3.5" hard disk drive (HDD) or a 5.25" DVD-RW without needing separate power source as compared to eSATA and USB 2. On a notebook eSATAp port can supply 5&nbsp;V to power up a 2.5" HDD/SSD as compared to eSATA. Many notebooks are now equipped with this combo port. A list of notebooks with this new port is available here [http://pcsg3.com/esatap.shtml]

eSATAp can be implemented in all machines with a spare SATA port. These machines include PC notebooks, desktops, Apple Mac Pro, and Linux or Unix servers. This makes eSATAp an easy, economical, cross platform solution for external storage.

==== Pre-standard implementations ====
*Prior to the final eSATA 3 Gb/s specification, a number of products existed designed for external connections of SATA drives. Some of these use the internal SATA connector or even connectors designed for other interface specifications, such as [[FireWire]]. These products are not eSATA compliant. The final eSATA specification features a specific connector designed for rough handling, similar to the regular SATA connector, but with reinforcements in both the male and female sides, inspired by the USB connector. eSATA resists inadvertent unplugging, and can withstand yanking or wiggling, which could break a male SATA connector (the hard-drive or host adapter, usually fitted inside the computer). With an eSATA connector, considerably more force is needed to damage the connector, and if it does break it is likely to be the female side, on the cable itself, which is relatively easy to replace.{{Citation needed|date=February 2007}}
*Prior to the final eSATA 6 Gb/s specification many add-on cards and some motherboards advertise eSATA 6 Gb/s support because they have 6 Gb/s SATA 3.0 controllers for internal-only solutions. Those implementations are non standard and eSATA 6 Gb/s requirements will be ratified in the upcoming SATA 3.1 specification.<ref>[http://www.serialata.org/documents/SATA-Revision-3.0-FAQ-FINAL.pdf]</ref> These products might not be eSATA 6 Gb/s compliant.

=== Terminology ===
The name SATA II has become synonymous with the 3&nbsp;Gbit/s standard.
In order to provide the industry with consistent terminology, the SATA-IO has compiled a set of marketing guidelines for the third revision of the specification.
* The SATA 6 Gb/s specification should be called ''Serial ATA International Organization: Serial ATA Revision 3.0''.
* The technology itself is to be referred to as ''SATA 6 Gb/s''.
* A product using this standard should be called the ''SATA 6 Gb/s [product name]''.
Using the terms ''SATA III'' or ''SATA 3.0'' to refer to a SATA 6 Gb/s product, is unclear and not preferred. SATA-IO has provided a guideline to foster consistent marketing terminology across the industry.<ref>http://www.serialata.org/developers/naming_guidelines.asp</ref>

== Cables, connectors, and ports ==
Connectors and cables present the most visible differences between SATA and parallel ATA drives. Unlike PATA, the same connectors are used on 3.5-inch SATA hard disks for desktop and server computers and 2.5-inch disks for portable or small computers; this allows 2.5-inch drives to be used in desktop computers with only a mounting bracket and no wiring adapter. Smaller disks may use the mini-SATA spec, suitable for small-form-factor Serial ATA drives and mini SSDs.<ref>{{cite web|url=http://techreport.com/discussions.x/17624 |title=Get ready for mini-SATA |publisher=The Tech Report |date=2009-09-21 |accessdate=2010-01-26}}</ref>

There is a special connector ([[eSATA]]) specified for external devices, and an optionally implemented provision for clips to hold internal connectors firmly in place. SATA drives may be plugged into [[Serial Attached SCSI|SAS]] controllers and communicate on the same physical cable as native SAS disks, but SATA controllers cannot handle SAS disks.

There are SATA ports (on motherboards of a PC) that can use SATA data cable with locks or clips, thus reducing the chance of accidentally unplugging while the PC is turned on. So does the same with SATA power connector and SATA data connector connected to a SATA HDD or SATA optical drive. Also, there is a right-angled connector on one end of some SATA data cables, which can be used when connecting to a SATA HDD or SATA optical drive.

{{Clear}}
=== Data ===
{| class="wikitable" style="float:right; margin-left:1em; margin-right:0; margin-top:0;"
|-
! Pin # !! Function
|-
| 1
| Ground
|-
| 2
| A+ (transmit)
|-
| 3
| A− (transmit)
|-
| 4
| Ground
|-
| 5
| B− (receive)
|-
| 6
| B+ (receive)
|-
| 7
| Ground
|-
| 8
| Coding notch
|-
| colspan="2" style="text-align:center;"|[[Image:SATA Data Cable.jpg|150px|A 7-pin Serial ATA data cable.]]
|-
|colspan="2"|<small>A 7-pin Serial ATA right-angle data cable.</small>
|}

The SATA standard defines a data cable with seven conductors (3 grounds and 4 active data lines in two pairs) and 8&nbsp;mm wide wafer connectors on each end. SATA cables can have lengths up to {{convert|1|m|ft}}, and connect one motherboard socket to one hard drive. PATA [[ribbon cable]]s, in comparison, connect one motherboard socket to up to two hard drives, carry either 40 or 80 wires, and are limited to {{convert|45|cm|in}} in length by the PATA specification (however, cables up to {{convert|90|cm|in}} are readily available). Thus, SATA connectors and cables are easier to fit in closed spaces and reduce obstructions to [[air cooling]]. They are more susceptible to accidental unplugging and breakage than PATA, but cables can be purchased that have a locking feature, whereby a small (usually metal) spring holds the plug in the socket.

One of the problems associated with the transmission of data at high speed over electrical connections is loosely described as ''noise''. Despite attempts to avoid it, some electrical coupling will exist both between data circuits and between them and other circuits. As a result, the data circuits can both affect other circuits, whether they are within the same piece of equipment or not, and be affected by them. Designers use a number of techniques to reduce the undesirable effects of such unintentional coupling. One such technique used in SATA links is [[differential signaling]]. This is an enhancement over PATA, which uses [[single-ended signaling]].

{{Clear}}

=== Power supply ===
==== Standard connector ====
{| class="wikitable" style="float:right; margin-left:1em; margin-right:0; margin-top:0;"
|-
!colspan="2"| Pin # !! Mating !! Function
|-
| colspan="3" style="text-align:center;"|&nbsp;— || Coding notch
|-
|rowspan=3 style="background:orange;" |
| 1
|align=right| 3rd
|rowspan=3| 3.3&nbsp;V
|-
| 2 ||align=right| 3rd
|-
| 3 ||align=center| 2nd
|-
|rowspan=3 style="background:black;" |
| 4
|align=left| 1st
|rowspan=3| Ground
|-
| 5 ||align=center| 2nd
|-
| 6 ||align=center |2nd
|-
|rowspan=3 style="background:red;" |
| 7
|align=center| 2nd
|rowspan=3| 5&nbsp;V
|-
| 8 ||align=right| 3rd
|-
| 9 ||align=right| 3rd
|-
| style="background:black;" |
| 10
|align=center| 2nd
| Ground
|-
| style="background:gray;" |
| 11
|align=right |3rd
| [[Staggered spinup]]/activity<br />(in supporting drives)
|-
| style="background:black;" |
| 12
| 1st
| Ground
|-
|rowspan=3 style="background:yellow;" |
| 13
|align=center| 2nd
|rowspan=3| 12&nbsp;V
|-
| 14 ||align=right| 3rd
|-
| 15 ||align=right| 3rd
|-
| colspan="4" style="text-align:center;"|[[Image:SATA power cable.jpg|200px|A 15-pin Serial ATA power connector.]]
|-
|colspan="4"|<small>A 15-pin Serial ATA power receptacle.<br/>This connector does not provide the extended<br/>pins 4 and 12 needed for [[hot-plugging]].<ref>https://raid.wiki.kernel.org/index.php/Hardware_issues#Hotplug_support_by_SATA.2FSAS_cables</ref></small>
|}
The SATA standard specifies a different [[power connector]] than the decades-old four-pin [[Molex connector]] found on pre-SATA devices. Like the data cable, it is wafer-based, but its wider 15-pin shape prevents accidental mis-identification and forced insertion of the wrong connector type. Native SATA devices favor the SATA power-connector, although some early SATA drives retained older 4-pin Molex in addition to the SATA power connector.

SATA features more pins than the traditional connector for several reasons:

* A third [[voltage]] is supplied, 3.3&nbsp;V, in addition to the traditional 5&nbsp;V and 12&nbsp;V.
* Each voltage transmits through three pins ganged together, because the small contacts by themselves cannot supply sufficient current for some devices. (Each pin should be able to carry 1.5&nbsp;A.)
* Five pins ganged together provide ground.
* For each of the three voltages, one of the three pins serves for [[hot swapping|hotplugging]]. The ground pins and power pins 3, 7, and 13 are longer on the plug (located on the SATA device) so they will connect first. A special hot-plug receptacle (on the cable or a backplane) can connect ground pins 4 and 12 first.
* Pin 11 can function for [[staggered spinup]], activity indication, or nothing. Staggered spinup is used to prevent many drives from spinning up simultaneously, as this may draw too much power. Activity is an indication of whether the drive is busy, and is intended to give feedback to the user through an [[LED]].<!--needs some rewording, see corresponding section on discussion page -->

Adapters that can convert a 4-pin [[Molex connector]] to a SATA power connector exist. However, because the 4-pin Molex connectors do not provide 3.3&nbsp;V power, these adapters provide only 5&nbsp;V and 12&nbsp;V power and leave the 3.3&nbsp;V lines unconnected. This precludes the use of such adapters with drives that require 3.3&nbsp;V power. Some 4-pin Molex to SATA power connectors have electronics included in the connector to also provide the 3.3 V power. Understanding this, drive manufacturers have largely left the 3.3&nbsp;V power lines unused.

{{Clear}}

==== Slimline connector ====
SATA 2.6 first defined the slimline connector, intended for smaller form-factors; e.g., notebook optical drives.
{| class="wikitable" style="float:left; margin-left:1em; margin-right:0; margin-top:0;"
|-
!colspan="2"| Pin # !! Function
|-
| style="background:gray;" |
| 1
| Device presence
|-
| style="background:red;" |
| 2
|rowspan=2| 5&nbsp;V
|-
| style="background:red;" |
| 3
|-
| style="background:gray;" |
| 4
| Manufacturing diagnostic
|-
| style="background:black;" |
| 5
|rowspan=2| Ground
|-
| style="background:black;" |
| 6
|}
[[Image:SATA Slimline Powercable.jpg|thumb|right|200px|A 6-pin Slimline Serial ATA power connector. Note that pin 1 (device presence) is shorter than the others.]]

{{Clear}}

==== Micro connector ====
The micro connector originated with SATA 2.6. It is intended for 1.8-inch hard drives. There is also a micro data connector, which is similar to the standard data connector, but is slightly thinner.
{| class="wikitable" style="float:left; margin-left:1em; margin-right:0; margin-top:0;"
|-
!colspan="2"| Pin # !! Function
|-
| style="background:orange;" |
| 1
|rowspan=2| 3.3&nbsp;V
|-
| style="background:orange;" |
| 2
|-
| style="background:black;" |
| 3
|rowspan=2| Ground
|-
| style="background:black;" |
| 4
|-
| style="background:red;" |
| 5
|rowspan=2| 5&nbsp;V
|-
| style="background:red;" |
| 6
|-
| style="background:gray;" |
| 7
| Reserved
|-
| style="background:gray;" |
| 8
|rowspan=2| Vendor specific
|-
| style="background:gray;" |
| 9
|}

{{Clear}}

== Protocol ==
=== Topology ===
[[Image:Sata host expansor en.gif|thumb|SATA topology: host&nbsp;– expansor - device]]

SATA uses a point-to-point architecture. The connection between the controller and the storage device is direct.

{{As of|2008|alt=Modern}} PC systems usually have a SATA controller on the motherboard, or installed in a PCI or PCI Express slot. Most SATA controllers have multiple SATA ports and can be connected to multiple storage devices. There are also port expanders or [[Port multiplier|multipliers]] that allow multiple storage devices to be connected to a single SATA controller port.

=== Encoding ===

Physical transmission uses a logic encoding known as [[8b/10b encoding]]. This scheme eliminates the need to send a separate clock signal with the data stream. The stream itself contains necessary synchronization information that allows for SATA host/drive to extract clocking. Use of [[8b/10b encoding]] means the stream is also DC-balanced, which allows the signals to be [[AC-coupled]].

Separate point-to-point AC-coupled [[low voltage differential signaling|LVDS]] links are used for physical transmission between host and drive.

== Backward and forward compatibility ==
=== SATA and PATA ===
At the device level, SATA and PATA ([[Parallel ATA|Parallel AT Attachment]]) devices remain completely incompatible—they cannot be interconnected. At the application level, SATA devices can be specified to look and act like PATA devices.<ref>
{{cite web |url=http://www.sata-io.org/documents/serialata%20-%20a%20comparison%20with%20ultra%20ata%20technology.pdf|title=A comparison with Ultra ATA Technology |format=PDF |publisher=SATA-IO |accessdate=12 July 2007}}</ref> Many motherboards offer a "legacy mode" option, which makes SATA drives appear to the OS, like PATA drives on a standard controller. This eases OS installation by not requiring a specific driver to be loaded during setup but sacrifices support for some features of SATA and, in general, disables some of the boards' PATA or SATA ports, since the standard PATA controller interface supports only 4 drives. (Often which ports are disabled is configurable.)

The common heritage of the ATA command set has enabled the proliferation of low-cost PATA to SATA bridge-chips. Bridge-chips were widely used on PATA drives (before the completion of native SATA drives) as well as standalone "dongles." When attached to a PATA drive, a device-side dongle allows the PATA drive to function as a SATA drive. Host-side dongles allow a motherboard PATA port to function as a SATA host port.

The market has produced powered enclosures for both PATA and SATA drives that interface to the PC through USB, Firewire or eSATA, with the restrictions noted above. [[Peripheral Component Interconnect|PCI]] cards with a SATA connector exist that allow SATA drives to connect to legacy systems without SATA connectors.

=== SATA 1.5 Gbit/s, SATA 3 Gbit/s and SATA 6 Gbit/s ===
The designers of SATA aimed for backward and [[forward compatibility]] with future revisions of the SATA standard.<ref>[http://www.hitachigst.com/hdd/technolo/SerialATA_white_paper.htm Serial ATA - Next Generation Storage Interface] Hitachi Global Storage Technologies.</ref>

== Comparisons with other interfaces ==
=== SATA and SCSI ===

[[SCSI]] uses a more complex bus, usually resulting in higher manufacturing costs. SCSI buses also allow connection of several drives (using multiple channels, 7 or 15 on each channel), whereas SATA allows one drive per channel, unless using a port multiplier.

SATA 3 Gbit/s offers a maximum bandwidth of 300&nbsp;MB/s per device compared to SCSI with a maximum of 320&nbsp;MB/s. Also, SCSI drives provide greater sustained throughput than SATA drives because of disconnect-reconnect and aggregating performance. In general, SATA devices link compatibly to [[Serial Attached SCSI|SAS]] enclosures and adapters, whereas SCSI devices cannot be directly connected to a SATA bus.

SCSI, SAS, and fibre-channel (FC) drives are typically more expensive so they are traditionally used in [[server (computing)|server]]s and [[disk array]]s where the added cost is justifiable. Inexpensive ATA and SATA drives evolved in the [[home computer|home-computer]] market, hence there is a view that they are less reliable. As those two worlds overlapped, the subject of reliability [[Hard disk drive#Disk failures and their metrics|became somewhat controversial]]. Note that, in general, the failure rate of a disk drive is related to the quality of its heads, platters and supporting manufacturing processes, not to its interface.

Serial ATA in the Enterprise has increased from 21.6% in 2006 to 27.6% in 2008.
http://www.serialata.org/documents/SATA-Rev-30-Presentation.pdf

=== SATA in comparison to other buses ===

{| class=wikitable
|-
!Name
!Raw bandwidth (Mbit/s)
!Transfer speed (MByte/s)
!Max. cable length (m)
!Power provided
!Devices per Channel
|-
| [[#External SATA|eSATA]]
|rowspan=2|3,000
|rowspan=2|300<ref name="wiki.riteme.site">{{cite web|url=http://wiki.riteme.site/wiki/8b/10b_encoding|title=Technologies That Use 8b/10b Encoding}}</ref>
|rowspan=2|2 with eSATA [[Host bus adapter|HBA]] (1 with passive adapter)
|{{No}}
|rowspan=4|1 (15 with [[port multiplier]])
|-
| eSATAp
|{{Yes|5&nbsp;V/12&nbsp;V}}<ref>{{cite web|url=http://www.delock.de/mail/esatap/esatap.html |title=eSATAp Application |publisher=Delock.de |date= |accessdate=2010-01-26}}</ref>
|-
| [[#SATA 6 Gbit/s (Third generation)|SATA 600]]
|6,000
|600<ref name="wiki.riteme.site"/>
|rowspan=3|1
|rowspan=3 {{No}}
|-
| [[#SATA 3 Gbit/s (Second generation)|SATA 300]]
|3,000
|300<ref name="wiki.riteme.site"/>
|-
| [[#SATA 1.5 Gbit/s|SATA 150]]
|1,500
|150<ref name="wiki.riteme.site"/>
|1 per line
|-
| [[Parallel ATA|PATA]] 133
|1,064
|133.5
|0.46 (18&nbsp;in)
|{{No}}
|2
|-
| [[Serial Attached SCSI|SAS 600]]
|6,000
|600<ref name="wiki.riteme.site"/>
|rowspan=3|10
|rowspan=3 {{No}}
|rowspan=3|1 (>65k with expanders)
|-
| [[Serial Attached SCSI|SAS 300]]
|3,000
|300<ref name="wiki.riteme.site"/>
|-
| [[Serial Attached SCSI|SAS 150]]
|1,500
|150<ref name="wiki.riteme.site"/>
|-
| [[FireWire]] 3200
|3,144
|393
|100 (more with special cables)
|rowspan=3 {{Yes|15&nbsp;W, 12–25&nbsp;V}}
|rowspan=3|63 (with hub)
|-
| [[FireWire]] 800
|786
|98.25
|100<ref name="Apple-FW-dev-notes">{{cite web |url=http://developer.apple.com/documentation/HardwareDrivers/Conceptual/HWTech_FireWire/Articles/FireW_concepts.html |title=FireWire Developer Note: FireWire Concepts |publisher=Apple Developer Connection |accessdate=13 July 2009}}</ref>
|-
| [[FireWire]] 400
|393
|49.13
|4.5<ref name="Apple-FW-dev-notes"/><ref name="16 cables">16 cables can be daisy chained up to 72&nbsp;m</ref>
|-
| [[Universal Serial Bus|USB]] 3.0*
|4,000
|400<ref name="wiki.riteme.site"/><!-- uses 8B10B encoding -->
|3<ref name="USB_3_Quickie_Intro">{{cite web|first=Louis E. |last=Frenzel |url=http://electronicdesign.com/Articles/ArticleID/19680/19680.html |title=USB 3.0 Protocol Analyzer Jumpstarts 4.8-Gbit/s I/O Projects |publisher=Electronic Design |date=September 25, 2008 |accessdate=3 July 2009}}</ref>
|{{Yes|4.5&nbsp;W, 5&nbsp;V}}
|rowspan=3|127 (with hub)<ref name="USB_3_Quickie_Intro"/>
|-
| [[Universal Serial Bus|USB]] 2.0
|480
|60<!-- 8bits/byte, no 8B10B encoding as with USB3.0 -->
|5<ref name="USB">USB hubs can be daisy chained up to 25&nbsp;m</ref>
|{{Yes|2.5&nbsp;W, 5&nbsp;V}}
|-
| [[Universal Serial Bus|USB]] 1.0
|12
|1.5
|3
|{{Yes}}
|-
|| [[SCSI]] Ultra-320
|2,560
|320
|12
|{{No}}
|15 (plus the HBA)
|-
| [[Fibre Channel]]<br/> over optic fiber
|10,520
|2,000
|2–50,000
|rowspan=2 {{No}}
|rowspan=2|126<br/>(16,777,216 with switches)
|-
| [[Fibre Channel]]<br/> over copper cable
|4,000
|400
|12
|-
| [[InfiniBand]]<br/>Quad Rate
|10,000
|1,000
|5&nbsp;(copper)<ref>{{cite web | url=http://download.intel.com/design/network/products/optical/cables/ornl.pdf | title=Infiniband Based Cable Comparison |accessdate=11 February 2008 | last=Minich | first=Makia | date=25 June 2007 | format=PDF }}{{Dead link|date=July 2009}}</ref><ref>{{cite news | first=Michael | last=Feldman | title=Optical Cables Light Up InfiniBand | date=17 July 2007 | publisher=Tabor Publications & Events | url=http://www.hpcwire.com/hpc/1729056.html | work=HPCwire | page=1 | accessdate = 11 February 2008}}</ref>
&lt;10,000&nbsp;(fiber)
|{{No}}
|1 with [[Point-to-point (telecommunications)|point to point]]<br/>Many with [[switched fabric]]
|-
| [[Light Peak]]
|10,000
|1,250
|100
|{{No}}
|Many
|}
:''* [[Universal Serial Bus|USB]] 3.0 specification released to hardware vendors 17 November 2008.''

Unlike PATA, both SATA and eSATA support [[hot-swapping]] by design. However, this feature requires proper support at the host, device (drive), and operating-system level. In general, all SATA devices (drives) support hot-swapping (due to the requirements on the device-side), also most SATA [[host adapter]]s support this command.<ref name=linux-ata>{{cite web|url=http://ata.wiki.kernel.org/index.php/Software_status#Hotplug_support |title=Software status - ata Wiki |publisher=Ata.wiki.kernel.org |date=2008-08-17 |accessdate=2010-01-26}}</ref>

SCSI-3 devices with SCA-2 connectors are designed for hot-swapping. Many server and RAID systems provide hardware support for transparent hot-swapping. The designers of the SCSI standard prior to SCA-2 connectors did not target hot-swapping, but, in practice, most RAID implementations support hot-swapping of hard disks.

[[Serial Attached SCSI]] (SAS) is designed for hot-swapping.

==Development tools==
When developing and/or troubleshooting the Serial ATA bus, examination of hardware signals can be very important to find problems. [[Logic analyzers]] and [[bus analyzer]]s are tools which collect, analyze, decode, store signals so people can view the high-speed waveforms at their leisure.

== See also ==
{{Portal|Computing}}
* [[libATA]]
* [[Advanced Host Controller Interface]] (AHCI)
* [[AT Attachment]] (ATA)
* [[FATA (hard drive)|FATA]]
* [[Native Command Queuing]] (NCQ)
* [[TRIM (SSD command)]]
* [[List of device bandwidths]]

== Notes and references ==
{{Reflist|2}}

== External links ==
{{Commons}}
* [http://www.sata-io.org/ Serial ATA International Organization (SATA-IO)]
* [http://www.edadesignline.com/howto/207402359 EETimes Serial ATA and the evolution in data storage technology, Mohamed A. Salem]
* [http://www.sata-io.org/documents/serialata10a.zip "SATA-1" specification, as a zipped pdf; Serial ATA: High Speed Serialized AT Attachment, Revision 1.0a, 7-January-2003].
* [http://web.archive.org/web/20070928100150/http://www.sata-io.org/docs/10a_ECN.zip Errata and Engineering Change Notices to above "SATA-1" specification, as a zip of pdfs]
* [http://www.sata-io.org/developers/naming_guidelines.asp Dispelling the Confusion: SATA II does not mean 3&nbsp;Gbit/s]
* {{PDFlink|[http://www.sata-io.org/documents/External%20SATA%20WP%2011-09.pdf SATA-IO White Paper - External SATA (eSATA)]|502&nbsp;kiB<!-- application/pdf, 514383 bytes -->}}
* [http://pinouts.ru/HD/serialATA_pinout.shtml SATA motherboard connector pinout]
* [http://www.intel.com/support/chipsets/imst/sb/CS-020825.htm AHCI/RAID Intel Matrix Storage Technology: Unattended installation instructions under Windows XP]
* [http://support.intel.com/support/chipsets/imsm/sb/CS-021736.htm Intel Matrix Storage Manager: How do I install an operating system on single serial ATA hard drive?]
* [http://www.allpinouts.org/index.php/Serial_ATA_(SATA,_Serial_Advanced_Technology_Attachment) Serial ATA Connector Schematic and Pinout]
* [http://www.serialata.org/documents/SATA_illus_guide_final.pdf Serial ATA server and storage use cases]
* [http://www.seagate.com/ww/v/index.jsp?locale=en-US&name=install-troubleshoot-sata-non-mac&vgnextoid=2b089d2c3c90e010VgnVCM100000dd04090aRCRD How to Install and Troubleshoot SATA Hard Drives]
* [http://www.lostcircuits.com/mambo//index.php?option=com_content&task=view&id=50&Itemid=46&limit=1&limitstart=0 Serial ATA and the 7 Deadly Sins of Parallel ATA]
* [http://www.hardwaresecrets.com/article/27 Everything You Need to Know About Serial ATA]
* [http://www.seagate.com/www/en-us/products/desktops/barracuda_hard_drives/barracuda_xt/ Barracuda XT - the first SATA 6Gb/s HDD]
* [http://forums.overclockers.co.uk/showthread.php?t=17504457 Mini-FAQ on SATA II (specifications/performance/compatibility)]

{{Computer-bus}}

{{DEFAULTSORT:Serial Ata}}
[[Category:Serial ATA| ]]
[[Category:Serial buses]]
[[Category:2003 introductions]]

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[[ko:SATA]]
[[hi:सीरियल ऐटा]]
[[id:Serial ATA]]
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[[ja:シリアルATA]]
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[[ur:سلسلی پیشرفتہ طرزی وابستہ]]
[[zh:SATA]]

Revision as of 13:43, 9 September 2010

THIS IS BORING

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