PC Hardware in a Nutshell, 3rd Edition

SATA Features

SATA has the following important features:

Reduced voltage

Current ATA standards use 5.0V or 3.3V (ATA-100/133). These relatively high voltages in conjunction with high pin densities make 100 MB/s the highest data rate that is realistically achievable. SATA uses 500 millivolt (0.5V) peak-to-peak signaling, which results in much lower interference and crosstalk between conductors.

Simplified cabling and connectors

SATA replaces the 40-pin/80-wire parallel ATA ribbon cable with a seven-wire cable. In addition to reducing costs and increasing reliability, the smaller SATA cable eases cable routing and improves airflow and cooling. An SATA cable may be as long as 1 meter (39+ inches), versus the 0.45-meter (18 inch) limitation of standard ATA. This increased length contributes to improved ease of use and flexibility when installing drives, particularly in tower systems. The smaller and less-expensive SATA connector replaces the large, cumbersome 40-pin connectors used by standard ATA.

Differential signaling

In addition to three ground wires, the seven-wire SATA cable uses a differential transmit pair (TX+ and TX-) and a differential receive pair (RX+ and RX-).

Improved data robustness

In addition to using differential signaling, SATA incorporates superior error detection and correction, which ensures the end-to-end integrity of command and data transfers at speeds greatly exceeding those available with standard ATA.

Operating system compatibility

SATA appears identical to PATA ...