[AI] an insight into USB 3.0

Srikanth Kanuri srilists at gmail.com
Fri Sep 10 06:11:46 EDT 2010


Transcend launched the new USB 3.0 hard drive so a look at USB 3.0:

Everything You Need to Know About USB 3.0:

No doubt you’re familiar with the Universal Serial Bus – we ranked it
as our top
PC innovation of all time.
But what do you know about the next version of this ubiquitous
interface? USB 2.0 (otherwise known as USB Hi-Speed) boosted the
original 12Mbps data rate
to 480Mmb/s over 10 years ago, and now USB 3.0 (dubbed USB Superspeed)
is set to multiply that bandwidth tenfold.

USB 3.0 will be backwards-compatible with USB 2.0

Like the upgrade from USB 1.1 to 2.0, the new 3.0 connectors and
cables will be physically and functionally compatible with hardware
from the older specs.
Of course, you won’t be able to maximize your bandwidth unless you’re
using a USB 3.0 cable with Superspeed devices and ports, but at least
plugging a
3.0 cable into a 2.0 port won’t blow up your PC. The spec’s
compatibility lies in the design of the new connectors. USB 2.0 cables
worked off of four lines
– a pair for in/out data transfer, one line for power, and the last
for grounding. USB 3.0 adds five new lines (the cable is noticeably
thicker), but the
new contacts sit parallel to the old ones on a different plane, as
opposed to being adjacent to them. This means you’ll be able to
differentiate between
2.0 and 3.0 cables just by looking at the ends.


At first glance, the USB 3.0 connector looks just like the 2.0 design

The maximum speed of USB 3.0 is 4.8Gbps or more in some devises.

It’s true: USB 3.0 SuperSpeed will be 10 times faster than the 480Mbps
limit of the 2.0 spec. The example Intel likes to give out when
talking about the
new speed is that transferring a 27GB HD movie to your future media
player will only take 70 seconds with USB 3.0, while it would take 15
minutes or more
with 2.0. Keep in mind that you’re only going to be able to take
advantage of this speed if your portable storage device can write data
that quickly. Solid
state devices will benefit most from the speed boost, while magnetic
hard disks will be limited by their RPM and corresponding read/write
speeds. Also,
new Mass Storage Device drivers will have to be developed for Windows
to take advantage of the spec.


Uploads and downloads are kept on separate data lanes

Remember those five new lanes we mentioned earlier? With USB 3.0, two
new lanes will be dedicated to transmit data, while another pair will
handle receiving
data. This not only accounts for the significant speed boost, but also
allows USB 3.0 to both read and write at the same time from your
portable storage
device. In the old spec, the pair of lanes used for data transfer
weren’t split between send and receive – they only could handle
traffic in one direction.
Bi-directional data transfer will be very useful for syncing up
information on PDAs and storage backup.


The packed guts of a USB 3.0 cable -- note that the cable will be
about as thick as a ethernet cable

USB 3.0 will charge more devices, quicker

Not only will USB 3.0 cables facilitate faster transfer speeds, but
they’ll carry more power, too. The USB-IF recognizes the growing
number of portable
devices that charge via USB (cellphones, MP3 players, digital
cameras), and have bumped the power output from about 100miliamps to
900 milliamps. That
means not only will you be able to power more than 4 devices from a
single hub, but the increase current will let you charge up heftier
hardware as well.



USB 3.0 will be more power efficient

One of the mandates of the new spec is more efficient power-usage
protocols. USB 3.0 abandons device polling in favor of a new
interrupt-driven protocol,
which means non-active or idle devices (which aren’t being charged by
the USB port) won’t have their power drained by the host controller as
it looks for
active data traffic. Instead, the devices will send the host a signal
to begin data transfer. This feature will also be backward compatible
with USB 2.0
certified devices.




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