Serial ATA (
SATA, abbreviated from
Serial AT Attachment)
[2] is a
computer bus interface that connects
host bus adapters to
mass storage devices such as
hard disk drives,
optical drives, and
solid-state drives. Serial ATA succeeded the older
Parallel ATA (PATA) standard,
[a] offering several advantages over the older interface: reduced cable size and cost (seven conductors instead of 40 or 80), native
hot swapping, faster
data transfer through higher signaling rates, and more efficient transfer through an (optional)
I/O queuing protocol. Although, a number of
hot plug PATA offering were first invented and marketed by
Core International beginning in the late 1980s for the
Micro Channel architecture bus controllers.
[3]
Prior to SATA's introduction in 2003, the PATA was simply known as ATA. The AT Attachment (ATA) name originated after the 1984 release of the
IBM Personal Computer AT, more commonly known as the IBM AT.
[4] The IBM AT was the first mass-produced computer where the hard disk was key to the system's performance. The IBM AT’s controller interface became a de facto industry interface for the inclusion of hard disks. “AT” was IBM’s abbreviation for “Advanced Technology”; thus, many companies and organizations indicate SATA is an abbreviation of “Serial Advanced Technology Attachment”; however, the ATA specifications simply use the name "AT Attachment", to avoid possible trademark issues with IBM.
[5]
SATA host adapters and devices communicate via a high-speed
serial cable over two pairs of conductors. In contrast, parallel ATA (the
redesignation for the legacy ATA specifications) uses a 16-bit wide data bus with many additional support and control signals, all operating at much lower frequency. To ensure backward compatibility with legacy ATA software and applications, SATA uses the same basic ATA and
ATAPI command sets as legacy ATA devices.
SATA has replaced parallel ATA in consumer desktop and laptop
computers; SATA's market share in the desktop PC market was 99% in 2008.
[6] PATA has mostly been replaced by SATA for any use; with PATA in declining use in industrial and embedded applications that use
CompactFlash (CF) storage, which was designed around the legacy PATA standard. A 2008 standard,
CFast to replace CompactFlash is based on SATA.
[7][8]
Serial ATA industry compatibility specifications originate from the
Serial ATA International Organization (SATA-IO). The SATA-IO group collaboratively creates, reviews, ratifies, and publishes the interoperability specifications, the test cases and
plugfests. As with many other industry compatibility standards, the SATA content ownership is transferred to other industry bodies: primarily the
INCITS T13 subcommittee ATA, the INCITS
T10 subcommittee (
SCSI), a subgroup of T10 responsible for
Serial Attached SCSI (SAS). The remainder of this article will try to use the terminology and specifications of SATA-IO.