From: Spiro Trikaliotis (trik-news_at_gmx.de)
Date: 2003-07-10 21:39:03
Hello Rainer,
On Thu, Jul 10, 2003 at 08:02:41PM +0200, Rainer Buchty wrote:
> USB1 already was 12Mbps, USB2 extends to 480Mbps.
>
> The problem is not the transmission speed but latency. With USB you just
> don't have a guarantee that packets are delivered in time -- and if you do
> isochronous transfer you don't have a guarantee that transmission was ok.
Just read yesterday: With USB, you have the "interrupt transfer". It's
completely prescheduled and allows up to 64 byte per frame (1 µs). That
should be enough even for the 1541, without need for isochronous transfer.
The latency I'm afraid of is the OS overhead when dealing with USB. It could
be possible to avoid it under plain DOS, but in this case, you'd have the
completely control the OHCI/UHCI/EHCI interface.
Spiro.
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