Thursday, 16 January 2014

Superspeed USB 3.0

The third generation of the USB interface introduced in 2008. Called "SuperSpeed USB 3.0" (SS USB), it provides a 10x increase from 480 Mbps to 4.8 Gbps and also reduces CPU overhead by no longer continuously polling attached devices. In practice, USB 3.0 devices do not achieve a 1000% speed increase. For example, a USB 3.0 external hard drive may provide only a 50% improvement over its USB 2.0 counterpart, because the drive's latency and circuitry are limiting factors.

Plugs and Sockets Are Different
Although additional pins were added to 3.0, older USB 2.0 plugs insert into 3.0 sockets for backward compatibility. Type A 3.0 plugs can be inserted into 2.0 sockets, but only Type A. That is not the case with Type B 3.0 and Micro-B 3.0 plugs, because they have a larger footprint .

SuperSpeed USB 10 Gbps (USB 3.1) from the USB-IF
The SuperSpeed USB 10 Gbps (USB 3.1) Specification adds a 10 Gbps speed mode that uses a more efficient data encoding and will deliver more than twice the effective data through-put performance of existing SuperSpeed USB over enhanced, fully backward compatible USB connectors and cables. The specification extends the existing SuperSpeed mechanical, electrical, protocol and hub definition while maintaining compatibility with existing USB 3.0 software stacks and device class protocols as well as with existing 5 Gbps hubs and devices and USB 2.0 products.
•Delivers 10 Gbps USB data rate
     *  2x improvement over current SuperSpeed USB 5 Gbps data rate
•Improved data encoding for more efficient data transfer leading to higher through-put and improved I/O power efficiency
•Compatible with existing USB 3.0 software stacks and device protocols
•Works with both existing 5 Gbps and new 10 Gbps USB 3.0 hubs and devices, as well as USB 2.0 products

As technology innovation marches forward, new kinds of devices, media formats, and large inexpensive storage are converging. They require significantly more bus bandwidth to maintain the interactive experience users have come to expect. In addition, user applications demand a higher performance connection between the PC and these increasingly sophisticated peripherals. USB 3.0 addresses this need by adding an even higher transfer rate to match these new usages and devices.
USB continues to be the answer to connectivity for PC, Consumer Electronics, and Mobile architectures. It is a fast, bidirectional, low-cost, dynamically attachable interface that is consistent with the requirements of the PC platforms of today and tomorrow.
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.

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