Date   : Sat, 06 Mar 1999 20:53:10 +0000
From   : Tom Lees <tom@...>
Subject: Re: Econet, etc.

On Sat, Mar 06, 1999 at 02:40:27PM +0100, Mark Usher wrote:
> Hi
> 
> > Just wondering how difficult it would be to emulate Econet.
> Pass.

It looks like I'm going to have to find a datasheet for the 68B54 somehow
to even know if it'll be difficult :(

> > I'd be most grateful for any info anyone has AT ALL on Econet - what
> > hardware, ROMs, etc. you need for a file server, controller
> > specs, hardware
> > specs, etc. Info on the actual protocols on the wire might be
> > interesting as
> > well (then maybe I can make up an Econet-PC adapter on the serial port :)
> 
> Well for a Level II file server you need (min) a BBC, 6502 copro and a disc
> drive.

> Level III (min) a BBC, 6502 copro, and a hard drive

Any idea as to why the copro was needed?

And where can I get the ROMs, SW, or whatever I need for this. I'd pay for
it, but I doubt I'd find any. So unless anyone out there actually HAS these
and wants to send me an image, I'm probably stuck. The 6502 copro shouldn't
be a problem, since I got that emulated pretty well(*) recently.

> The BBC's (or Masters) should also have the network interface fitted,
> obviously :-)

Out of interest, was there ever a network interface for the Electron?
(presumably it would just be an expansion-port device with Econet
suitably displaced into FRED, and the ROMs suitably modified to cope).

> Apart from that you will need a "clock", this is really a simple pulse
> generator, that generates the timing for the network. The circuit diagram
> for it can be found in the Adv Econet User guide which you can download from
> the BBC Documentation Project web site.

Ah. Now I do actually have one of these. Its in a black box marked "Econet"
and "Acorn Computer" in green writing, and it also has two 5-pin DIN
sockets, and 12V AC PSU. Inside, it seems to have a PCB marked "Econet 2",
and about 5 links.

I just also found a website called the "Econet Enthusiansts page". Its
a bit scanty on hard info (like registers on the 68B54 etc.), but
it informs me that this is a "Level 2 Clock box", and that its better
than a "Level 1 Clock box". Was there ever a level 3 clock box?

The URL BTW is: http://www.argonet.co.uk/users/rmurray/econet/
It seems to be somewhat archimedes-centric too, unfortunately.

> There were also some dedicated systems, but I don't really know much about
> them.

Not having actually read the Econet AUG, I don't know if it gives the
protocols, but if it does, I could emulate these on the input into my
"Beeb with Econet" emulator, and it could then get files from a share I
supply here on my Linux box.

> Acorn also produced a ISA card for PC's called an Ecolink. I have one in
> this machine at the moment. It will work fine under DOS and Win95/98, except
> for mapping drives. This is a limitation of the driver and will only work
> under DOS 3.3 due to the directory formats being changed in DOS after this
> time. I have tried to hack this but with little success.

Any idea where I can get one of these?

(*) Actually, it now works in all situations EXCEPT when I try to use it
with the Master MOS+ 3.50. Any ideas why? HiBASIC, etc. seem to work fine,
and View{,sheet,store,...} all report around 48K free memory. Also, it
doesn't beep (CTRL+G beep) on startup. Is that normal?

-- 
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