What Is an eSATA Connector?

ESATA is a data interface. When it comes to the interface of external storage devices (such as mobile hard disks), everyone will think of USB2.0 or IEEE1394 by accident. Although the data transmission rates of these two interfaces have reached 480Mbps / 400Mbps, they cannot really realize the maximum potential of devices such as hard disks. This is because USB2.0 or IEEE1394 mobile hard disks must use bridge chips to achieve interface conversion. This connection method will undoubtedly greatly affect the performance of the device. Now a brand new interface technology quietly comes to everyone-eSATA, in a word, its characteristics are: it is 6 times faster than USB2.0!

eSATA

ESATA is a data interface. When it comes to the interface of external storage devices (such as mobile hard disks), everyone will think of it

The full name of eSATA is External Serial ATA (External Serial ATA), which is an external extension of the SATA interface

Although eSATA is only an extension of the SATA interface, and the manufacturer does not need to make any modification to the SATA protocol and processing chip, but to ensure that SATA is safely moved out of the chassis and passed the review of the SATA-IO international organization, there must be many The place needs improvement.

The first feature that the eSATA interface needs to provide is hot swap. At present, in addition to the old PC external interfaces such as serial ports and parallel ports, many other interfaces, including USB and IEEE1394, support hot-swap technology, and eSATA, an interface that specializes in storage devices, supports hot-swapping. . You may ask, doesn't the SATA specification include hot-plug technology? Why does eSATA need to add the same thing? In fact, the existing SATA1.0 standard controllers on many motherboards do not support the hot-swap function. When the user removes the SATA device while the system is running, it is likely to cause

In order to ensure that SATA is safely moved out of the case and passed the audit of SATA-IO International Organization, the industry needs to solve the following problems:

(1) Preventing electrostatic discharge when the connector is connected;

(Two) meet

eSATA is an external interface to SATA, but comes with more durable cables and connectors. eSATA can achieve SATA-like transfer speeds, such as SATA 1.5Gb / s or SATA 3Gb / s. eSATA 3Gb / s speed is also backward compatible with 1.5Gb / s, which is the same as the current situation of desktop hard drives. Because the internal data transmission rate of the hard disk has reached 75MB / sec, the USB and 1394 interface speeds have become the bottleneck of external hard disks. At the same time, eSATA peripherals can also be used after a system crash inside the host.

To use eSATA, your PC must have two conditions:

(1) One is that your motherboard must have a SATA2 interface;

(2) The other is to have an external eSATA conversion interface, such as the ASRock 775XFire-eSATA2 + motherboard, which was launched in 2006 ^[1]

In addition to strengthening the hot-swap specifications, the eSATA interface must also be redesigned to meet external connection requirements. The original SATA cables and interfaces in the chassis did not have any protection and locking devices, and the interface part was also quite fragile. In general, the SATA interface inside the chassis is prone to problems due to poor contact after about 50 plugs and unplugs. Such an interface design is undoubtedly fatal to external equipment! After all, no one wants their eSATA hard drive to be scrapped after several insertions or slight collisions.

As an external connection standard, eSATA must meet the requirements in terms of strength, resistance to electromagnetic interference, and cable flexibility. Therefore, the interfaces and cables of the eSATA device are all metal shielded. The all-metal shield design not only reduces electromagnetic interference, but also helps reduce static electricity generated during hot plugging. At the same time, in order to prevent the interface from being accidentally disconnected by external forces, the eSATA standard also requires a metal shrapnel-type locking device to be installed at the cable interface. According to tests, the newly designed interface of eSATA will ensure that the device can be hot-plugged at least 2000 times.

eSATA can also provide up to 4 SATA interfaces on a SATA channel through a port multiplexing chip. As the transmission rate of the SATA interface in the SATA2.5 specification reaches 300MB / s, the internal transmission rate of today's fastest SATA hard disks is only 80MB / s. Through a simple port multiplexing chip, a SATA channel can be shared by four eSATA devices to achieve higher connection density. Of course, the cumulative maximum transfer rate of eSATA storage devices sharing the same channel cannot exceed 300MB / s.

Finally, the eSATA interface also needs to comply with standards in terms of PCB wiring and power in order to obtain the eSATA certification mark issued by SATA-IO. Although most SATA hard disks can work on the eSATA interface at this stage, these bare hard disks are prone to failure because there is no corresponding protective casing and power supply system. SATA-IO recommends that users purchase certified eSATA external storage devices and boards whenever possible.

Mobile hard disk enclosure with eSATA interface

In terms of implementation cost, eSATA is undoubtedly more advantageous. For traditional USB or IEEE 1394 external devices, to read and write data from the hard disk via USB or IEEE1394 interface, an interface conversion circuit must be used, and the cost of this conversion circuit is 5 to 10 US dollars. In addition, the delay of the interface conversion has a great impact on the data transmission speed. Tests have shown that the IEEE 1394 speed loss rate (loss speed ratio peak speed) reached 20%, and USB 1.0 and USB 2.0 reached 33% respectively And 25%, and the speed loss of SATA is 0. This is because SATA and PATA are based on the eSATA protocol, so no protocol conversion is required during the transmission process. This not only saves costs, but also does not affect the performance of the hard disk.

What eSATA can bring to people

With the emergence of Blu-ray recorders and other devices, the original USB2.0 and IEEE1394 interfaces are obviously unable to meet the data transmission requirements of these recording devices, and it is common to produce recording failures. With the eSATA interface, an external optical drive can easily obtain the same performance and stability as the built-in optical drive, which fundamentally solves the problems of unsuccessful transfer rates and poor stability of external optical storage devices.

It is also worth mentioning that the eSATA secure hot-swap feature also gives SATA storage devices the opportunity to occupy the near-line and offline storage markets with their large capacity and extremely low prices. Users only need to plug in eSATA hard disks on these servers, and they can quickly increase the overall storage capacity by 500GB, or even more, without having to restart the computer during the entire process.

eSATA is a new generation of external device interface derived from the SATA interface. Although there is currently no USB2.0 or IEEE1394 more popular, it is believed that the eSATA interface will continue to be improved in the near future. At that time, the eSATA standard will gain a lot of popularity. . Small changes have made us gain a lot. It can be said that eSATA makes it easier for users to connect external devices, and also allows us to feel the "flying" general transmission speed.