PATA, (Parallel Advanced Technology Attachment) was the original interface to connect hard disks to desktop computers, originating in 1986. SATA (Serial ATA) was launched in 2002, and provided faster speeds, and SATA II provided even faster speeds. eSATA (Extended Serial ATA), which is faster than SATA II, allows drives to be connected externally, whereas with the previous technologies, only internal connections were possible. With the ability to connect external drives came the issue of choosing the appropriate eSATA connector, and while other external hard drives may connect using USB 2.0 or FireWire 400 or 800, the eSATA connector is distinct from these, as well as from the internal connector. eSATA connectors are also hot pluggable, meaning the cable running to it can be connected and disconnected while the computer is running without requiring a shut-down for safety.
External hard drives can be made with one or more ports, so a single hard drive might be able to connect to a computer with, both USB 2.0 and an eSATA connector. In order for an external hard drive to be connected to a computer, the hard drive and computer must each have an eSATA connector, and the user must own a suitable eSATA cable, which can be a maximum of 6.56 ft (2 m) in length. eSATA standards for connectors, cables, and signals were released in 2004.
The eSATA connectors are designed to prevent the substitution of internal cables that are unshielded for external cables. Additionally, to limit the risk of damage from electrostatic discharge (ESD), the plug is inserted farther into the connector before it is in place than was previously the case — .26 in (6.6 mm) instead of .20 in (5 mm). The eSATA connector has metal contact points and retention springs built into the top and bottom of the shield, and it is designed for more than 5000 insertions and removals. The eSATA logo is reserved for eSATA connectors, and other products, that meet the SATA specification guidelines and are members of SATA-IO (the Serial ATA International Organization®). Any eSATA product, including an eSATA connector, that was designed prior to the standard should be avoided, according to SATA-IO.
