Date   : Wed, 27 Jul 2005 13:59:04 +0000
From   : Jules Richardson <julesrichardsonuk@...>
Subject: Re: Econet-Ethernet bridge

On Wed, 2005-07-27 at 13:44 +0200, Eelco Huininga wrote:
>  
> > -----Oorspronkelijk bericht-----
> > Van: Majordomo List Manager [mailto:majordomo@...] 
> > Namens Jules Richardson
> > Verzonden: woensdag 27 juli 2005 12:50
> > Aan: bbc-micro@...
> > Onderwerp: RE: [BBC-Micro] RE: Econet-Ethernet bridge
> > 
> > Hence the reason I like the idea of interfacing the an Econet 
> > module to
> > a PC, and letting the PC worry about routing and whatever other
> > hardware's attached (plus things like running as an Econet 
> > fileserver if
> > needs be). The PC hardware can change with the times without 
> > redesign of
> > anything. Note that PC doesn't even mean IBM-compatible; 
> > could be a Mac
> > or a RiscPC or whatever - anything that supports a common OS 
> > between the
> > hardware (hence going for Linux or *BSD would seem sensible, with a
> > software project fork for those wanting Windows say)
> 
> Hmmm interesting approach. It would be nice to have some sort of Ecolink
> device available.

Certainly - handy for backups or for getting data onto the old machines,
or for (easily) making a fileserver or (easily) letting the machine act
as a gateway.

(well, second option perhaps not so easy due to need for mapping Econet
station numbers to IP addresses as you've previously mentioned, but I'm
sure it's not that hard)
 
> > So, possibly USB or serial are the choices. Maybe both is an option as
> > at least from a hardware point of view the interface is likely trivial
> > compared to an all-in-one board with its own CPU. 
> 
> IMHO this just shifts the problem from ISA to Serial or USB. Some modern x86
> motherboards have removed the serial connectors alltogether and only have
> USB connectors. And USB will be replaced in 5 or 10 years time by who knows
> what.

I agree it's a problem. But it's only in the last couple of years that
ISA's died out, 10 years (more?) after it was theoretically replaced by
more modern buses. Serial's probably got a good 5 years left on modern
hardware (with a few exceptions from some manufacturers), and I reckon
USB's probably got at least 15 years left to run, if not more. Purely
because they're simple interfaces for which to build hardware for. The
only real need to replace them is for reasons of speed, but there are
always going to be low-cost devices around that'll keep them alive.

It is hopefully less of a problem though (versus a complete system
approach) because less effort / expense is needed to design and build
the hardware (because it's as simple as possible) - so less is lost at
the point that it needs to be redesigned in x years.

>  I think that an Econet-Ethernet bridge should have all it's stuff
> on-board, without an ISA/USB/... bus.
> If you'd go with the serial Ecolink device, you'd have to make a choice for
> one interface or another. And this isn't a bad thing. As long as the design
> is well documented, someone can redesign it for the needs in the future.

Agreed it'd be difficult to do both (and wouldn't necessarily make sense
financially). I don't even know if serial's a possibility though given
Econet speeds. (Nor do I know if USB's viable). Maybe it's all too slow
to make this practical anyway :-)

The major selling point of an interface (versus self-contained system)
is that you don't care about what the interface is connected to. All
that's needed are interface drivers for the OS (or, given time, all the
major OSes) - the OS already handles the routing and network stack, and
it's irrelevant what (if any) network hardware exists on the "other"
side of the link - providing a driver exists for for it, then it can be
used. You can't do that with a self-contained system; you're stuck with
one type of network interface only and need yet more hardware to do
anything else.

> > At the very least, I'd urge any project to keep details of driving an
> > Econet module as a seperate area from the rest, as it'd then 
> > be valuable input for anyone trying the other approach...
> 
> I couldn't agree with you more :-)

Good :) I'll have to see what Econet docs I have - I believe I've got a
few low-level ones... not sure if I have anything on the computer-
interface side of the Master Econet module though (which would be a
useful thing to see!). 

I can possibly lay my hands on about 40 Econet modules if needs be
too...

cheers

Jules