--- David Laight <david@l8s.co.uk> wrote: > 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.

My laptop doesn't go into 100% usage when I use the ne0 pcmcia network
adapter (which I think is simplex)...what do you mean exactly?
Obviously its not as good as a cardbus/pci network adapter (it takes
more cpu time compared to a desktop with a pci adapter) because it
lacks dma/bus mastering. Does it use interrupt driven PIO?

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

100Mbit adapters are only available for cardbus.

> 
> 	David
> 
> [1] and a 5v card, the cycle times for 3.3v cards are larger....
> 
> -- 
> David Laight: david@l8s.co.uk 

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