eSATA Port

The common interface for external devices is called eSATA, that stands for External Serial Advanced Technology Attachment. When one uses a USB or Firewire external drive, they are actually using an ATA or Serial ATA hard drive and an external enclosure. The Serial ATA interface is used for internal hard drives. It competes with universal serial bus (USB) 2.0 and also Firewire 400. Thus, one can get a faster data transfer speed by using an external hard drive.

Features
You will find that the Practical Data Transfer rates are higher than the USB or Firewire Ports. It has the same protocol like the SATA port and therefore, one can use the port with minimum modification. One advantage is that low-level drive features like S.M.A.R.T. that do not function with USB or Firewire will work on the port. There is lesser electromagnetic interference between devices due to an extra layer of shielding. These connectors are not easy to break and have a specific life of about 500 insertions and removals. The maximum cable length is about 2 meters (6.6 feet). The maximum speed for data transfer is about 150 Mbps or 200MBps.

eSATA vs SATA
The eSATA is subset of the additional specifications given for the SATA. eSATA is not a necessary specification for your device, but one can add it as an extension to controller as well as other devices. Both the controller and device needs to support SATA, in order for eSATA to work. This point is important as the initial SATA controllers could not support Hot Plug capability. This is very important for functioning of external interface.

Another argument for eSATA vs SATA is the physical connectors. eSATA is a part of the interface specifications of SATA. But eSATA uses different physical connectors from the internal SATA connectors. These connecters provide better shield in case of high-speed serial lines when transferring signals from EMI protection. The eSATA cable length is 2m as compared to the 1m cable length for internal cables. This is the main reason, why one should not interchange the cables while using the different ports.

eSATA vs USB
USB 2.0 is an easy to use, highly compatible interface that is used on desktop PCs, notebooks, Window or Apple servers. But, there is one disadvantage of the USB 2.0, it is limited to 480 Mb/s and can translate into 30-35 MB/s maximum bandwidth when using the typical storage applications. The USB 3.0 launched in early 2010 is said to have a theoretical maximum rate of 5Gbps that makes it 10 times faster. It is also said to be full duplex that means it can download and upload simultaneously. The eSATA speed compared to USB 3.0 is similar to the internal SATA 1.0 bus. This means it has a theoretical speed of about 3Gbps. So, USB 3.0 is faster than this port.

eSATA vs Firewire 800
If you are wondering eSATA vs Firewire 800 - which is better, then definitely eSATA is the better of the two. Firewire is a built-in port on most of the Macs and provides good performances for uses such as boot drive in a mutli-drive system. You will find that even though eSATA may be running at slower speeds than its actual potential, the overall performance would be better than Firewire 800. Firewire is 2.2 times faster when it reads and writes.

The reason why you should go in for an eSATA external hard drive is that it is not that expensive. You can even extend your SATA connectors with expansion cards that are under 30 USD. There is no translation involved in eSATA and therefore, it does not take long for the data to be transferred. This means the data transfer rate is fast, about 1.5Gbps to 3GPs standard.