On Fri, Oct 10, 2003 at 04:18:24PM -0400, Gary Thorpe wrote:
>  --- David Laight <david@l8s.co.uk> wrote: > > I suspect that the
> problem is at least in part that PCMCIA may not
> > > be up to 100Mbits/sec (I don't know what its capabilities are, but
> > > have heard that assertion before).  I might do better if I forced
> > > 10Mbits/sec via ifconfig.
> > 
> > PCMCIA isn't really up to 10Mb/s.....
> > 
> > 	David
> > 
> > -- 
> > David Laight: david@l8s.co.uk 
> 
> I think PCMCIA can do 2 MB/s maximum, which is more than 10 Mb/s
> (roughly 1.25MB/s).

I don't have the specs any more, but I think you can actually get
memory cycles to 500ns [1] (IO cycles are slower) giving 4MB/s for
16bit transfers.  So 10M ethernet is 'only' about 1/3 of the bandwidth.
But not that your entire system is busy for this fraction of the
time regardless of the cpu speed.

With a carefully written driver 10M should be ok, 10M FDX might cause
problems, 100M is right out!

	David

[1] and a 5v card, the cycle times for 3.3v cards are larger....

-- 
David Laight: david@l8s.co.uk