What's eSATA?

The full name of eSATA is external serial ATA (external serial ATA), which is an external extension specification for SATA interfaces. In other words, eSATA is the "external" version of SATA, which is used to connect external and not internal SATA devices. For example, with the eSATA interface, you can easily connect the SATA hard drive to the motherboard's eSATA interface without having to open the chassis to replace the SATA hard drive. Relative to the SATA interface, eSATA in the hardware specifications of some changes in the data line interface connection with the addition of metal shrapnel to ensure the physical connection of the solid.

The original SATA is the use of L-shaped plugs to distinguish between the direction of the interface, and eSATA through the plug on the upper and lower end of the different thickness and groove to prevent mistakenly inserted, it also supports hot-plug. Although the interface is changed, but the physical specifications of the eSATA are not changed, the 7-pin data line is still used, so it is only necessary to change the interface to achieve the compatibility of SATA devices.

The eSATA interface is flat and the SATA interface is L-shaped.

The highest data transfer rate for an average 3.5-inch hard drive is 60mb/s, and the interface speed of USB2.0 or IEEE 1394 becomes a bottleneck in data transmission when using an external 3.5-inch hard drive box. If you use an external RAID 0 storage device, the maximum 480Mbps interface bandwidth can severely limit the performance of your hard drive. Therefore, eSATA is a very good solution. and eSATA hard drive box with SATA hard drive, the middle of the need for bridging chip conversion, is a raw storage device interface.

eSATA characteristics

Although eSATA is only an extension of the SATA interface, and the manufacturer does not need to make any modifications to the SATA protocol and processing chips, it is necessary to ensure that SATA is securely moved out of the chassis and approved by the Sata-io International organization.

The first feature that the eSATA interface needs to provide is hot-swappable. At present, in addition to the old serial port, and other PC external interface, including USB, IEEE1394, and many other interfaces support hot-swappable technology, and eSATA this specifically for the storage Device service interface to support the meaning of hot plug more important. You might ask, did the SATA specification already contain hot-swappable technology? Why does eSATA need to add the same thing? In fact, the SATA 1.0 standard controllers on many existing motherboards do not support hot-swappable functionality, Unplugging a SATA device while the user is running the system is likely to cause the system to crash. To address this problem, the SATA 2.5 specification has been further enhanced for hot-swappable security and reliability.

Compared with the common USB2.0 and IEEE1394 two common external interfaces, the eSATA's biggest advantage is the ability to transmit data. The theoretical transmission speed of eSATA can reach 1.5Gbps or 3Gbps, much higher than that of USB2.0 480Mbps and IEEE 1394 400Mbps. In the actual test, copying a 1.36GB size file from a computer to an external storage device with different interfaces, the eSATA interface device takes much less time than USB2.0 or IEEE 1394 devices, nearly one times faster. With the advent of eSATA, the transmission rate of external interface is much higher than the internal transmission rate of hard disk and other devices.

In the realization of cost, eSATA undoubtedly more advantages. For traditional USB or IEEE 1394 external devices, to read and write data from the hard disk via a USB or IEEE 1394 interface, you must use an interface conversion circuit that costs 5~10 dollars. In addition, the delay of interface conversion has a great effect on the speed of data transfer, and it has been tested that the speed loss rate of IEEE 1394 (loss rate is higher than peak speed) reached 20%,usb1.0 and USB2.0 respectively to 33% and 25%, while Sata's speed loss is 0, This is because SATA and Pata are all based on the ATA protocol, so the transfer process does not require protocol conversion, which not only saves costs, and hard disk performance is not affected!