The USB 3.0 is finally here! Or rather should we say SuperSpeed USB 3.0. This third version of the Universal Serial Bus promises very high performance compared to USB 2.0 "Hi-Speed" while maintaining compatibility with all USB products legacy. On paper, USB 3.0 delivers performance 10 times greater than USB 2.0 with a theoretical maximum throughput of 4.8 Gbps cons 480 Mbps for USB 2.0. As a reminder, USB 1.0 proposed a throughput of 12 Mbps. Returning to the story elsewhere on the USB.
A little history first ...
The USB standard was created in 1996 with main objective to improve the connectivity of devices with the PC. At the time it still struggles with parallel ports and serial ports and it is not always easy to configure everything. At the root of the USB standard, there are companies such as Compaq, Digital, IBM, Intel, Northern Telecom and Microsoft. The latter proudly launches the concept of Plug and Play with the advent of USB it is true that facilitates the connection of various devices under Windows. In April 2000 is the USB 2.0 but is validated at the end of 2001 by the USB IF (USB Implementers Forum).It will then wait until November 2008 that the specifications of USB 3.0 will be unveiled and the end of 2009 that the first products compatible with the third revision of the USB appear on the market.
USB 3.0: Flow promising!
This USB 3.0 is announced for a theoretical speed of 4.8 Gbps SuperSpeed by bus. In practice, the specifications of USB 3.0 it should consider building on a speed of 3.2 Gbps or 400 MB / s. But let us remember that USB 2.0 promises 480 Mbps, or 60MB / s while the very vast majority of USB devices capped at 30-35 Mb / s. In short, if our test gives an idea of performance, only time will tell what maximum speed can be expected.
SuperSpeed This standard operates in full duplex and therefore requires 2 pairs of 2 son in more than two son dedicated to the data "no SuperSpeed" mean by that, when connected with USB 2.0 or earlier. It also has 2 son for land and food, and a new wire that acts as a shield of protection. The result of new connectors (still compatible with USB 2.0 connectors) to support these entire son and a thicker cable. Some connectors USB 2.0 are still applicable (Standard-A, Standard B, Micro-B) in terms of form, but additional contacts are implemented in the USB 3.0 connectors. In short, the form of some slots does not change but new contacts are emerging. To remain in the field wiring, note also that the USB 3.0 supports a maximum length of 3 meters, at least if one wants to preserve the maximum transfer rate. To recall the length of standard USB 2.0 and 1.1 were in the same conditions set at 5 meters.
Four states of energy management appear to reduce consumption among other active but mostly at the level of consumption in idle that significant progress can be expected both at the device from the apparatus to which this latter is connected. To achieve USB 3.0 eliminates the need for "polling" which is to continuously interrogate the device to see if information transfer or not. With USB 3.0, the host asks the device once it has data to transfer and if the answers no, host not ask more. This is the device to communicate when it has data to transfer. That will be very beneficial for the autonomy of laptops. A note still in this area than USB 3.0 delivers more power, which will allow faster recharging devices that we plug in as USB phones, PDAs and other MP3 players. As a bus properly configured can deliver 150 mA load per unit for a total of 900 mA against only 500 for USB 2.0.