What is SATA or Serial ATA?

SATA or Serial ATA (Advanced Technology Attachment) is the latest generation drive interface, following the traditional Parallel ATA (PATA).

SATA cable connected to a drive.

Anyone who has ever accessed a computer is familiar with the 40-wire flat parallel cables that connect the hard drive, CD-ROM, and other devices to your controllers. PATA has been the standard and has served well, but it also has drawbacks. Cables limited to 18 inches (46 cm) in length often make connections difficult and also block housings by obstructing airflow, while cooling has become crucial. Although rounded cables became available, the most advanced PATA drives (Ultra ATA / 133) reached the maximum parallel transfer rate of 133 MB/ps. With the speed of CPUs, RAM and system buses improving, designers realized that PATA would soon be a bottleneck for the efficiency of advanced drives in the system architecture.

SATA cable.

Type SATA.

Serial ATA has important distinct advantages over its predecessor. The cables are very thin, with small 7-pin connectors. They can be up to 3 feet (1 meter) long and are easily routed out of the way, allowing maximum airflow inside the case. SATA also has a much lower power requirement of just 250 mV compared to PATA’s 5 volt requirement, and with chip core voltages going down this speaks well of the future of SATA. Serial ATA does away with Master/Slave settings and drive jumpers. Setup is greatly simplified and the technology even allows for hot swapping, which means drives can be removed or added while the computer is running.

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However, the most promising feature of Serial ATA is that it eliminates the transfer limit hit by PATA. The first generation has a maximum transfer rate of 150 MBps and the second generation SATA offers around 300 MBps. A third-generation SATA set for 2009, “SATA 6 Gb/s” will provide nearly twice the speed of the previous SATA iteration.

With the introductory transfer speed so close to existing Ultra ATA/133 speeds, the increase in real-world performance is negligible for first-gen SATA, although the drive prices are comparable to PATA drives, making the switch to the new technology a good choice when upgrading, building or purchasing a new system. Motherboards with built-in SATA and PATA interfaces are widely available to accommodate both types of drives, and there are no restrictions on using both types in the same system. Serial ATA is also a good choice for RAID and is intended to replace PATA.

For older systems, third-party SATA controllers can be placed in any PCI slot if you buy a SATA drive. (A parallel Ultra ATA drive can also be used via a PATA to SATA adapter, although the drive’s performance will suffer as the adapter must convert the data stream from parallel to serial.)

If you are upgrading your motherboard, purchasing SATA enabled will allow ease of use for future SATA drives, even if your current drives are standard ATA.

Note: When using some third-party devices or adapters, hot-swapping support may be missing or “quirky”. It is always recommended to backup valuable data before risking loss.

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