1.2.2.6 Connection: SATA

The SATA (serial ATA) bus is a serialized IDE bus, but with additional enhancements. Despite the serial nature, SATA has a higher transfer rate compared to the fastest IDE standard. Furthermore, many SATA controllers also supports RAID (redundant array of inexpensive drives) for reliability.

Unlike IDE, an SATA interface is dedicated to a single disk drive. Rather than a restriction, this is actually a feature! Due to the lost cost of SATA controller ICs, connectors and cables, it is very cost effective to add ICs, connectors and cables for additional hard disks. The dedicated nature of SATA means that different disk drives in a PC each has a maximum transfer rate of 3Gbps for SATA II, and 1.5Gbps for SATA. This property of SATA makes it very suitable for RAID applications.

Other improvements of SATA (over IDE) also enhance the performance of SATA controllers and disk drives. A notable feature is called NCQ (native command queuing). It allows the disk drive optimize commands received from the controller, and hence improving the throughout of a hard disk. This feature is most noticable for applications that require a lot of disk accesses.

Due to the serial nature of SATA, the connection cables are fairly thin and easy to handle. This property also makes it possible to make external hard disk enclosures for SATA hard disks. At a transfer rate of 3Gbps, an SATA II external hard disk can transfer data 5 times faster than a USB external hard disk.