buffalocheese writes "Since the introduction of the Serial ATA 1.0a specification in 2002, many manufacturers have introduced PCI and CardBus cards with both internal and external SATA connections. At first these internal and external connectors were completely identical, but later, external connectors started to appear which were still fully compatible with the internal sockets but featured added extra screening for external use. With the introduction of the SATA II specification in mid 2004 a new external SATA connector was defined. These new external (eSATA) connectors are not compatible with the original internal SATA connection. Currently there are add-on cards and drive housings available which feature both types of SATA connection for external use. Gradually the older types will disappear and all new SATA cards will feature the eSATA connector for external drive connections."