ramuEldo fantHagiro

A bus line(also known as a bus) is used to connects the parts of the CPU to each other. It is also used to link the CPU to others components on the system board.Every computer system has two basic categories of buses that are system buses and expansion buses. The expansion buses is the one who connects the CPU to others component and one type of this expansion buses is Universal Serial Bus (USB).

Universal Serial Bus has commonly used today and the most popular one as it supports several external devices without using expansion cards or slots.USB also generally used and replace the serial and parallel ports.USB also has become standard connection of devices like mouse,mp3 player,printers and many more. There are three generation of USB currently such as USB 1.0,USB 2.0,and the latest is USB3.0.

USB3.0 is the latest generation of USB and all people are waiting for it.This version seemly called Super Speed USB3.0 as it speed is upgraded to highest theoretical top of 5Gbit/sec...THAT'S AMAZING!!:)-ramuEldo




HOW DOES USB3.0 ACHIEVE THE EXTRA PERFORMANCE?

USB 3.0 achieves the much higher performance by way of a number of technical changes. Perhaps the most obvious change is an additional physical bus that is added in parallel with the existing USB 2.0 bus. This means that where USB 2.0 previously had 4 wires (power, ground, and a pair for differential data), USB 3.0 adds 4 more for two pairs of differential signals (receive and transmit) for a combined total of 8 connections in the connectors and cabling. These extra two pairs were necessary to support the SuperSpeed USB target bandwidth requirements, because the two wire differential signals of USB 2.0 were not enough.

Furthermore, the signaling method, while still host-directed, is now asynchronous instead of polling. USB 3.0 utilizes a bi-directional data interface rather than USB 2.0's half-duplex arrangement, where data can only flow in one direction at a time. Without getting into any more technical mumbo jumbo, this all combines to give a ten-fold increase in theoretical bandwidth, and a welcome improvement noticeable by anyone when SuperSpeed USB products hit the market.



WHAT OTHERS IMPROVEMENT USB3.0 PROVIDED?

The enhancements to SuperSpeed USB are not just for higher data rates, but for improving the interaction between device and host computer. While the core architectural elements are inherited from before, several changes were made to support the dual bus arrangement, and several more are notable for how users can experience the improvement that USB 3.0 makes over USB 2.0:

* More power when needed
o 50% more power is provided for unconfigured or suspended devices (150 mA up from 100 mA), and 80% more power is available for configured devices (900 mA up from 500 mA). This means that more power-hungry devices could be bus powered, and battery powered devices that previously charged using bus power could potentially charge more quickly.
o A new Powered-B receptable is defined with two extra contacts that enable a devices to provide up to 1000 mA to another device, such as a Wireless USB adapter. This eliminates the need for a power supply to accompany the wireless adapter...coming just a bit closer to the ideal system of a wireless link without wires (not even for power). In regular wired USB connections to a host or hub, these 2 extra contacts are not used.

* Less power when it's not needed
Power efficiency was a key objective in the move to USB 3.0. Some examples of more efficient use of power are:
o Link level power management, which means either the host computer or the device can initiate a power savings state when idle
o The ability for links to enter progressively lower power management states when the link partners are idle
o Continuous device polling is eliminated
o Broadcast packet transmission through hubs is eliminated
o Device and individual function level suspend capabilities allow devices to remove power from all, or portions of their circuitry not in use

* Streaming for bulk transfers is supported for faster performance

* Isochronous transfers allows devices to enter low power link states between service intervals

* Devices can communicate new information such as their latency tolerance to the host, which allows better power performance

To paint an accurate picture, not everything in USB 3.0 is a clear improvement. Cable length, for one, is expected to have a significant limitation when used in applications demanding the highest possible throughput. Although maximum cable length is not specified in the USB 3.0 specification, the electrical properties of the cable and signal quality limitations may limit the practical length to around 3 metres when multi-gigabit transfer rates are desired. This length, of course, can be extended through the use of hubs or signal extenders.

Additionally, some SuperSpeed USB hardware, such as hubs, may always be more expensive than their USB 2.0 counterparts. This is because by definition, a SuperSpeed hub contains 2 hubs: one that enumerates as a SuperSpeed hub, and a second one that enumerates as a regular high-speed hub. Until the USB hub silicon becomes an integrated SuperSpeed USB + Hi-Speed USB part, there may always be a significant price difference.

Some unofficial discussion has surfaced on the web with respect to fiber-optic cabling for longer cable length with USB 3.0. The specification makes no mention of optical cabling, so we conclude that this will be defined in a future spec revision, or left to 3rd party companies to implement cable extension solutions for SuperSpeed USB.

edited from: http://www.everythingusb.com/superspeed-usb.html










SuperSpeed USB brings significant performance enhancements to the ubiquitous USB standard, while remaining compatible with the billions of USB enabled devices currently deployed in the market. SuperSpeed USB will deliver 10x the data transfer rate of Hi-Speed USB, as well as improved power efficiency.

* SuperSpeed USB has a 5 Gbps signaling rate offering 10x performance increase over Hi-Speed USB.
* SuperSpeed USB is a Sync-N-Go technology that minimizes user wait-time.
* SuperSpeed USB will provide Optimized Power Efficiency.No device polling and lower active and idle power requirements.
* SuperSpeed USB is backwards compatible with USB 2.0. Devices interoperate with USB 2.0 platforms. Hosts support USB 2.0 legacy devices.

edited from: http://www.usb.org/developers/ssusb


By the way,the release of USB3.0 actually is the proof of development of "Internet World" nowadays. As the technologies is going on time by time,people can make work simpler and faster by using this technologies.Who would have thought,after this maybe there are more faster of transferring data other than USB3.0. Maybe after this,i should get it one!hehe.. Last word, USB 3.0 a.k.a SuperSpeed USB,what an awesome!!!:)-ramuEldo