SATA: The Serial ATA Interface for Storage Devices

Serial ATA (SATA) is the standard interface for connecting storage devices — hard drives, SSDs, and optical drives — to computer motherboards. It replaced the older Parallel ATA (PATA, also called IDE) interface beginning in 2003. ## Versions | Version | Year | Bandwidth | Common Name | |---------|------|-----------|-------------| | SATA I | 2003 | 1.5 Gbit/s | SATA 150 | | SATA II | 2004 | 3.0 Gbit/s | SATA 300 | | SATA III | 2009 | 6.0 Gbit/s | SATA 600 | SATA III at 6 Gbit/s (~550 MB/s practical throughput) is sufficient for mechanical hard drives (which max out around 200 MB/s) but is the bottleneck for modern SSDs, which drove the adoption of NVMe. ## Connectors SATA uses two separate physical connectors: **Data connector:** 7-pin L-shaped connector carrying the serial data signal. Thin, flexible cable. **Power connector:** 15-pin connector delivering three voltage rails — 3.3V, 5V, and 12V. The 5V and 12V rails each have TVS diode protection on the drive's PCB to guard against overvoltage. The 15-pin SATA power connector replaced the older 4-pin Molex connector. **Critical safety note:** SATA power cables from modular PSUs are NOT interchangeable between manufacturers or even between models from the same brand. The device-side connector is standardized but the PSU-side pinout is not — using the wrong cable can reverse polarity and destroy drives. Modular PSU Cables Are Not Interchangeable: A Common Cause of Drive Death ## Current Status SATA remains the dominant interface for mechanical hard drives, budget SSDs, and optical drives. High-performance storage has largely moved to NVMe (via M.2 or U.2 form factors), which offers dramatically higher bandwidth (up to 32 Gbit/s for PCIe 4.0 x4) and lower latency by communicating directly over the PCIe bus rather than through the SATA controller.