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SATA

technology Maturity 11-13 Next article →

SATA, which stands for Serial AT Attachment, is a vital computer bus interface.

Serial ATA logo
Serial ATA logo

It acts as a communication bridge between a host bus adapter and various mass storage devices. These devices include hard disk drives, solid-state drives (SSDs), and optical drives. This interface is essential for modern computing because it allows the computer to read and write data reliably.

ST3400820AS
ST3400820AS

Without such an interface, the system could not interact with its permanent memory.

To understand how SATA works, we must look at its serial mechanism. SATA host adapters and devices communicate using a high-speed serial cable.

SATA power cable
SATA power cable

This cable utilizes two pairs of conductors to transmit information. This is a major change from the older Parallel ATA (PATA) standard. PATA used a 16-bit wide data bus with many additional support and control signals. PATA operated at a much lower frequency than SATA. By using fewer conductors, SATA reduces cable size and lowers production costs.

SATA2
SATA2

A SATA cable uses only seven conductors, whereas PATA required 40 or 80.

One of the most useful features of SATA is native hot plugging.

SATA2 und eSATA-Stecker
SATA2 und eSATA-Stecker

This means a device can be inserted or removed from a backplane connector while the system has power. After insertion, the device initializes and begins to operate normally. This capability requires support from the host, the device, and the operating system. For external connections, eSATA supports hot plugging only when used in AHCI mode. If a controller operates in IDE emulation mode, it will not support this feature. While hot swapping is convenient, users should note that unwritten data may be lost if power is removed unexpectedly.

To access advanced features like hot plugging and Native Command Queuing (NCQ), systems use the Advanced Host Controller Interface (AHCI).

Super Talent 2.5in SATA SSD SAM64GM25S
Super Talent 2.5in SATA SSD SAM64GM25S

AHCI is an open host controller interface that has become a standard used by Intel. If AHCI is not enabled by the motherboard or chipset, the controller typically uses "IDE emulation" mode. In this emulation mode, the SATA controller cannot access advanced features not supported by the legacy ATA standard. Most modern operating systems, such as newer versions of Windows, Mac OS X, and Linux, include built-in support for AHCI. Older systems, like Windows XP, may require proprietary drivers to access these advanced SATA capabilities.

SATA has evolved through several technical revisions to increase data speeds.

SATA 6 Gbit-s controller, in form of a PCI Express card
SATA 6 Gbit-s controller, in form of a PCI Express card

Revision 1.0 was released in early 2003 with a native rate of 1.5 Gbit/s. This resulted in an actual uncoded transfer rate of 1.2 Gbit/s, or 150 MB/s. Revision 2.0 arrived in April 2004 and doubled the throughput to 3 Gbit/s. This version also introduced Native Command Queuing (NCQ) to improve multitasking performance. Revision 3.0 was released in May 2009 and reached speeds of 6 Gbit/s. This version provides a maximum uncoded transfer rate of 4.8 Gbit/s, or 600 MB/s. All these revisions are backward compatible, meaning newer controllers can work with older drives.

The history of this technology traces back to the IBM Personal Computer AT, released in 1984. The "AT" in AT Attachment refers to this "Advanced Technology" computer. Before the year 2000, the industry used the PATA standard, often simply called ATA. Seagate, APT, and Vitesse announced the first Serial ATA disc drive at the Intel Developer Forum in August 2000. The world's first SATA hard disk drive was the Seagate Barracuda SATA V, released in January 2003.

PATA hard disk with SATA converter
PATA hard disk with SATA converter

By 2008, SATA had become dominant, holding a 99% market share in the desktop PC market.

As storage technology has advanced, SATA has branched into new specialized forms. Revision 3.1 introduced mSATA, which is a small connector used for solid-state drives in mobile devices.

Intel 525 mSATA SSD
Intel 525 mSATA SSD

Revision 3.2 introduced the SATA Express specification. This interface combines both SATA and PCI Express buses, allowing them to coexist. This combination can reach a theoretical throughput of 1969 MB/s. Another standard, M.2, is a small form factor implementation of the SATA Express interface.

M.2 and mSATA SSDs comparison
M.2 and mSATA SSDs comparison

These various iterations ensure that SATA remains a flexible and powerful standard for the digital age.

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🖼️ Images & Media (16)
File:Serial ATA logo.svg
Serial ATA logo.svg
File:ST3400820AS.jpg
ST3400820AS.jpg
File:Super Talent 2.5in SATA SSD SAM64GM25S.jpg
Super Talent 2.5in SATA SSD SAM64GM25S.jpg
File:SATA 6 Gbit-s controller, in form of a PCI Express card.jpg
SATA 6 Gbit-s controller, in form of a...
File:SATA2.jpg
SATA2.jpg
File:SATA power cable.jpg
SATA power cable.jpg
File:ESATA Logo.svg
ESATA Logo.svg
File:SATA2 und eSATA-Stecker.jpg
SATA2 und eSATA-Stecker.jpg
File:Connector esata IMGP6050 wp.jpg
Connector esata IMGP6050 wp.jpg
File:Esatap port.JPG
Esatap port.JPG
File:Intel 525 mSATA SSD.jpg
Intel 525 mSATA SSD.jpg
File:SATA Express connectors on a computer motherboard.jpg
SATA Express connectors on a computer...

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