[Tfug] USB 2.0 vs. firewire? (was: webcam question)

[JD Rogers]

> You say firewire has extra bandwidth?  Isn't USB 2.0 480 mbps and firewire
> only 400?

In 'theory', yes. In practice, USB2.0 is crap. I've worked with
'scientific' cameras that have usb2 interface and it is a crap shoot.
If you are lucky enough to find the right combination of usb2
controller and device on the right system, you might get close to
firewire, but mostly you get dropped frames and frustration out your
butt. I think it has to do with the difference in protocol, and
firewire is peer-to-peer so it is more stable or something. In any
case, you never realize how crappy usb2 is if you are just
transferring data (like from a usb hard drive), but when you are
trying to deal with data that is time sensitive (like video frames),
it is the pits.

Another problem is the power. I think the spec's on the power supplied
over usb are not always met by the usb controller. Especially on
laptops. This leads to flaky operation of the devices.

But it is cheaper and I am very thrifty.
JDR

>
> >From: John Gruenenfelder <johng at as.arizona.edu>
> >Reply-To: Tucson Free Unix Group <tfug at tfug.org>
> >To: Tucson Free Unix Group <tfug at tfug.org>
> >Subject: Re: [Tfug] webcam question
> >Date: Wed, 11 Oct 2006 18:35:08 -0700
>
> >digital video device so you don't even need extra drivers.  And the extra
> >bandwidth of Firewire generally means better quality.
> >
> >
> >--
> >--John Gruenenfelder    Research Assistant, UMass Amherst student
> >                         Systems Manager, MKS Imaging Technology, LLC.
> >Try Weasel Reader for PalmOS  --  http://gutenpalm.sf.net
> >"This is the most fun I've had without being drenched in the blood
> >of my enemies!"
> >         --Sam of Sam & Max
> >
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