SHCC WYSIWYG Article from February 2010

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This article was written by Don VanSyckel, the club president, as a part of "The President's Pen".  This article appeared in the February 2010 WYSIWYG newsletter.

USB 3.0, What Does It Mean to You?

by Don VanSyckel

There's been reports of the coming USB 3 interface to PCs. It's reported to be available on some PCs now and I would suspect will be available soon on a add in card for older PCs. What does USB 3 mean to you? First, Universal Serial Bus (USB) is a very popular method of connecting peripherals to a PC. From USB 1.1 to USB 2.0 and now to USB 3.0 this protocol has been a real work horse.

Below is a table of the 'theoretical' bus speed and the 'real world' bus speed.

Theory
Data
Rate
Measured
Data
Rate
Interface
Type
12 Mbps8 MbpsUSB 1.1
480 Mbps320 MbpsUSB 2.0
4.8 GbpsTBDUSB 3.0
Gbps = giga bits per second (1,000,000,000)
Mbps = mega bits per second (1,000,000)

A little about what this all means. USB 1.1 and USB 2.0 are basically the same technology. As the electronics got better it was possible to increase the speed and USB 2.0 is 40 time the speed of USB 1.1. This is a great increase but like many other things peripherals such as hard disks, camera memory, scanner resolution (more data per scan) kept pushing to larger and larger. This pushed the need for an interface faster than USB 2.0.

USB 1.1 and USB 2.0 as stated are similar and the electrical connection s are exactly the same, only USB 2.0 can operate at a faster rate. In order to push the USB speed to the next level it was necessary to change the electrical connections from the four used by USB 1.1 and 2.0 to eight used by USB 3.0. The connectors are all the same size and shape and four of the eight USB 3.0 electrical connections are positioned so that a USB 2.0 peripheral connected to a USB 3.0 port will operate properly.

While USB 3.0 is 10 times the speed of USB 2.0 it is expected that it will accomplish a real world speed that is a higher percentage of it's theoretical speed than USB 2.0. This means that the expected performance increase will be more than a factor of 10. One of the things to note is that USB 3.0 is expected to run at a data rate higher than the fastest consumer peripherals can handle thus allowing the peripherals to run at their maximum data rate.

Competing with USB 3.0 is eSATA. Currently for external disks eSATA is probably the way to go leaving USB for other type peripheral such as printers, scanners, cameras, and thumb drives.

More on eSATA and why serial instead of parallel in future months.

End of Article

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