E-SATA technology is not new - it's called external SATA II specification is an industry standard interface extends Serial ATA (SATA) is. Note E-SATA is merely an extension of the SATA interface is used to connect an external rather than internal SATA devices. Simply put, it is through E-SATA technology, so that the external I / O interface SATA2 features, such as having a E-SATA port, you can easily SATA2 hard disk into the E-SATA interface without opening the case to replace the SATA2 hard disk.
SATA and SATA2, no difference in the socket, but the transmission rate, the former 150MB / S, which is 300MB / S, faster
SATA2 hard disk interface can be backward compatible with previous generation, but the transmission rate will only go to the generation level