Serial Advanced Technology Attachment II

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What Does Serial Advanced Technology Attachment II Mean?

Serial Advanced Technology Attachment II (SATA II) is the second generation of computer bus interfaces used to connect motherboard host adapters to high-capacity storage devices, such as hard/optical/tape drives. SATA II is a successor to parallel Integrated Development Environment (IDE)/Advanced Technology Attachment (ATA) interface technologies, which ran at 3.0 Gbps – a throughput rate that nearly doubled the initial SATA specification. SATA II standard delivers additional improvements to SATA, which is provided in increments.


SATA II is also known as SATA 2 or SATA 2.0.

Techopedia Explains Serial Advanced Technology Attachment II

SATA II was introduced in 2002 to provide higher data transfer rates (DTR) for server and network storage requirements. Subsequent SATA II releases focused on enhanced cabling, failover capabilities and higher signal speeds.

SATA II features include:

  • Hot Plugging: This feature helps users to change or remove storage devices even when the computer is running.
  • Staggered Spin-Up: Allows sequential hard disk drive startup, which helps even out power load distribution during system booting.
  • Native Command Queuing (NCQ): Usually, the commands reach a disk for reading or writing from different locations on the disk. When the commands are carried out based on the order in which they appear, a substantial amount of mechanical overhead is generated because of the constant repositioning of the read/write head. SATA II drives make use of an algorithm to identify the most effective order in which to carry out commands. This helps to reduce mechanical overhead and improve performance.
  • Port Multipliers: Allows the connection of up to 15 drives to a SATA controller. This facilitates the building of disk enclosures.
  • Port Selectors: Facilitates redundancy for two hosts connected to a single drive, allowing the second host to take over in the event of a primary host failure.

In 2010, large quantities of SATA II interfaces were shipped in PCs and server chipsets.


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Margaret Rouse
Technology Expert
Margaret Rouse
Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.