Serial ATA

Serial ATA is a new standard in hard drive technology. Existing ATA hard drives (also known as IDE drives) have maxed out at the current ATA100 standard due to technological limitations of the signaling used (one manufacturer supports ATA133). ATA100 can transfer data between the hard drive and your computer at a maximum rate of 100 MB/s. Serial ATA, by contrast, starts at a maximum speed of 150 MB/s and is expected to increase substantially over time.

Serial ATA changes the signaling to use a serial connection, allowing for a much smaller cable to improve airflow inside the case. The serial connection also allows for a longer cable length; the new 1 meter limit would allow for external drives, competing with FireWire, SCSI, and USB 2.0 drives. In the future, Serial ATA will also allow for hot-swapping drives while a system is still powered on.

One change is that serial ATA drives use a point-to-point connection. The elimination of master/slave jumpers makes drives easier to set up but limits the hardware to one drive per cable. As a result computers will likely come with ATA100 connectors for several years to accommodate older hardware.

For the near term Serial ATA seems to be targeted more towards servers and higher end workstations. Most Serial ATA drives available so far are designed using higher speed internal components to take advantage of the faster bus speed, therefore the cost is much higher than today's ATA100 drives (which now start well under $100).

Currently Serial ATA is available as an add-on to any PC. Longer term, component manufacturers will improve Serial ATA integration, allowing for even faster speeds.

April 2003

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