On Apr 30, 2012, at 2:03 PM, Cameron Kaiser
wrote:
  > [...]
because USB is
> one-way
 Since when? 
 I think David is referring to its polled nature. 
 
 Yes, I suppose "asymmetric" would have been a better term.  It's
 not peer-to-peer like serial ports or 1394 are, which is what would
 make it nearly useless for kernel debug; that's before you get to
 issues of protocol stack, which 1394 gets away with by using DMA on
 the controller, which is questionable from a security standpoint but
 great for kernel debug. 
 Or perhaps "half-duplex", although USB 3.0 claims full-duplex
 capability.