Serial ATA Technology Explained

Introduced in the mid 1980's, the Advanced technology Attachment, ATA interconnect soon because the industry standard parallel input, output bus interface for connecting internal storage devices. Ultra ATA, which builds on the original parallel ATA interface, has become the most common used type of interconnect.

But in recent years, sharing digital video and audio files over high speed networks and other data intensive uses have placed greater demands on hard drives, optical drives and media storage peripherals. So, not surprisingly Ultra ATA now faces competition from a new technology, serial ATA, SATA.

As the name implies, this new interconnect uses a serial bus architecture instead of a parallel one. Serial ATA currently supports speeds up to 150 MBps. Further enhancements aim to boost rate as high as 600 MBps.

Compared with Ultra ATA, Serial ATA offers distinct advantages, including point to point topology that enables you to dedicate 150 MBps to each connected device. Each channel can work independently and unlike the "master, slave" shared bus of Ultra ATA, there is no drive connection or interface bandwidth sharing.

Compared with Ultra ATA's parallel bus design, Serial ATA requires a single signal path for sending data bits and a second path for receiving acknowledgement data. Each path travels across a 2 wire differential pair and the bus contains four signal lines per channel. Fewer interface signals means the interconnect requires less board space.

Serial ATA also uses thinner cables, no more than 6.3mm wide, that are available in longer lengths, up to 1M, as well as an improved connector design to reduce crosstalk. It also offers hot swappable capabilities.