Most of the devices now are USB compatable due to which it has made devices easy to use. The latest of the USB is USB 3.0 which hit the market this year.
What's New in USB 3.0?
High Transfer Rate:
This new SuperSpeed interface provides realistic transfer rates of around 3,200 Mbits/s or 3.2 Gbits/s. The theoretical top signaling rate is at 4.8 Gbits/s.
Data Transfer
USB 3.0 introduces full duplex data transfer. Two of five lanes are reserved for transmitting data, while another pair is dedicated to receiving data, meaning that USB 3.0 can read and write data simultaneously at full speed. Previous USB specifications did not support bi-directional data transfer.
Power
The unit load has been increased to 150 mA and a configured device can draw up to six unit loads, which adds up to 900 mA. This exceeds USB 2.0 by 80% and leads to faster recharging or powering of more than four devices from a single hub. In addition, the minimum device operating voltage was dropped from 4.4 V to 4 V, which saves energy.
Power Management
USB 3.0 suspends device polling, which is replaced by interrupt-driven protocol. As a result, idle devices won’t experience a power drain since a signal from the device is required to initiate data transfer. With USB 2.0 the host controller used to look for active transfers, slowly draining power. Briefly, USB 3.0 supports idle, sleep, and suspend states, as well as link-, device-, and function-level power management (Wikipedia).
USB 3.0 Advantages
Compatibility
USB 3.0 is backwards compatible with USB 2.0. So whether you get a new USB 3.0 device or a new computer that supports USB 3.0, your old device will be able to communicate with the new interface. Naturally, it will do so at the old USB 2.0 speed. However, you won’t be able to use a USB 3.0 cable to connect a USB 2.0 device.
Transfer Rate
Now I bet all this Megabit and Gigabit per second numbers sound impressive, but what does it actually translate to? Well, let me give you an example. With USB 3.0 you could transfer a 10 GB file from your computer to an external drive in approximately 25 seconds. With USB 2.0 this would take more than five minutes.
Benefits
The devices that will benefit most from USB 3.0 are those that already outspeed USB 2.0, including HD webcams, Blu-Ray drives, or some external hard drives.
Support by Operating Systems
Windows Vista, Windows 7, and Linux already support USB 3.0. Mac is expected follow. Given its age, Windows XP will probably not receive an update to support the new interface.
Disadvantages
Cable
The maximum cable length USB 3.0 supports is reduced to approximately three meters, opposed to five meters with USB 2.0. However, using hubs, the maximum length can be extended to 18 meters.
Speed Limit
Naturally, not all devices will be able to make use of the increased speed in USB 3.0. Magnetic hard drives for example, are limited by their RPM and the corresponding read/write speed. Hence, USB 3.0 will not unfold its full beauty until computers are equipped per default with faster hardware, such as solid state drives. But we all know how speedy progress is in the IT world. Give it a year or two and you will be able to fully benefit from USB 3.0.
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