Date   : Fri, 29 Jul 2005 12:38:29 +0000
From   : Jules Richardson <julesrichardsonuk@...>
Subject: Re: Econet-Ethernet bridge

On Fri, 2005-07-29 at 13:22 +0200, Johan Heuseveldt wrote:
> Hi,
> 
> On Fri 29 Jul, Mike Howard wrote:
> > BeebMaster wrote:
> 
> > > I don't think the spare sockets on the Acorn Econet Bridge are for
> > > "additional" RAM beyond the 8K it is meant to have.  I reckon that
> > > the design was originally based around 4 2K RAM chips later replaced
> > > by a single 8K RAM chip when they became more common/cheaper etc
> 
> It doesn't seem logical to me that only one of the four sockets could
> be upgrade from 2K to 8K. Having only 8K puts restrictions on the
> packet size. I think Mike got it right; see later.
> But a good schematic would give the answer.

Does it actually have to do much though? I mean isn't functionality just
a case of watching packets on each network interface and if they're not
destined for that interface, write them out to the other interface?  I'm
surprised much memory's needed to do that.

I know next to nothing about the high level Econet protocols, but I'm
surprised the bridge needs to maintain any kind of state (and therefore
need much memory)

Presumably larger packet sizes really hit performance on the network, so
they were typically pretty small.

cheers

Jules