On Oct 23, 2009, at 1:47 PM, Barry Gershenfeld wrote:

> USB 3 operates at 5 gigabits/sec (like PCI-Express), ... One  
> naturally wonders why we couldn't all just use External PCI-E.

Is there such a thing (external PCI-E)?

USB, for better or worse, deals with all the thorny issues like  
defining what the cables look like, ensuring backward compatibility  
with older USB peripherals, etc.  It wouldn't do to have the back of  
the computer end up with separate USB1, USB2, and USB3 ports for  
different classes of devices, especially if they all look about the  
same.  (although this is pretty much what happens if you upgrade your  
old system with an add-on card, and/or still have legacy hubs, and/or  
etc.)

BillW

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