Serial ATA (SATA): interface for connecting hard drives and optical drives

Specifications and components

SATA is defined in successive revisions that increased link speed and added features. Commonly referenced revisions are:

• SATA I (1.5 Gbit/s),
• SATA II (3.0 Gbit/s),
• SATA III (6.0 Gbit/s).

These signaling rates are the nominal interface speeds; real transfer rates are reduced by protocol overhead and other factors. The standard supports hot-plugging (connecting and disconnecting drives while the system is powered), native command queuing (NCQ) to reorder I/O for better throughput, and the Advanced Host Controller Interface (AHCI) for operating system interaction. A typical SATA data cable is a thin, keyed cable about one meter or shorter in length, contrasted with the wide ribbon cables used by PATA.

History and development

SATA emerged in the early 2000s to address limitations of PATA: bulky cables, limited device topology (two devices per cable), and slower transfer characteristics. Over time the SATA family broadened to include variants and related form factors. mSATA and the 2.5‑inch SATA form factor were developed to use the same protocol in smaller devices. eSATA offered an external connector for direct-attached external drives. Later efforts such as SATA Express attempted to combine SATA and PCIe lanes, but the industry has largely moved toward M.2 and NVMe SSDs for high-performance, low-latency storage.

Uses, examples and comparisons

SATA remains the predominant interface for spinning hard drives and many consumer SSDs because it balances cost, capacity and compatibility. Typical uses include internal desktop HDDs, 2.5‑inch laptop drives, and optical drives. In contrast, NVMe drives use the PCI Express (PCIe) bus and the NVMe protocol to achieve much higher throughput and lower latency; these drives are commonly available in M.2 and add-in card form factors and are replacing SATA SSDs in thin laptops and high-performance systems.

Practical features and distinctions

• Connectors: 7‑pin data plus 15‑pin power for standard SATA devices.
• One device per cable: simplifies device addressing compared with PATA's multi‑device ribbon cables.
• Backwards compatibility: newer SATA controllers and devices are generally interoperable with older revisions, though limited to the lower negotiated speed.
• External options: eSATA provides a dedicated external port without USB/SATA bridge overhead.

Notable facts and future outlook

Although SATA has been the dominant interface for consumer storage for many years, market trends show an increasing shift toward NVMe over PCIe for performance-sensitive applications and for compact devices where M.2 form factors are practical. Nevertheless, SATA remains important for high-capacity, cost-sensitive storage—particularly mechanical HDDs—and for legacy compatibility in many systems. For more technical details or official specifications consult the standard overview here, and for information on legacy PATA/IDE usage see this reference.