[Tfug] USB 2.0 vs. firewire?

Brian Masur bcmasur at hotmail.com
Thu Oct 12 16:15:03 MST 2006


>From: Shawn Nock <nock at email.arizona.edu>
>Reply-To: Tucson Free Unix Group <tfug at tfug.org>
>To: Tucson Free Unix Group <tfug at tfug.org>
>Subject: Re: [Tfug] USB 2.0 vs. firewire?
>Date: Thu, 12 Oct 2006 14:25:26 -0700
>
>Brian Masur wrote:
> > You say firewire has extra bandwidth?  Isn't USB 2.0 480 mbps and 
>firewire
> > only 400?
>
>That is true, but it is my understanding that nearly all firewire host
>chipsets are OHCI and off-load most of the processing required for data
>transfer on the bus to the fw chipset. Most USB host chipsets are UHCI
>(1.x)/EHCI (2.0) on x86/x64 platforms and require the processor to
>interrupt for data transfer.

I didn't know USB didn't have it's own processor.  Sounds like the same 
difference between IDE/ATA/SATA and SCSI.  That would definitely make things 
slower when you need all of the main processor for multimedia or other 
crunching.  Also, I thought OHCI was just certain vendors implementations of 
USB, didn't think it had anything to do with firewire.

Learn something every day.






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