Waaaay back in 2003 a chap called Paul Fellows emailed me:

Your list of Achimedes Machines is incomplete - and I am
selling the missing link right now. It is an A500 - only 100 ever
made, pre-dates the A305 by 1 year. 50 Used for devleopment and
50 sold to Olivetti for 9600 each. How did I get this? Well, I
was the man wot invented Arthur/RiscOS and I've had it since 85
when we did all that.

Interested? Its on ebay at the moment :-)

THAT Paul Fellows? Certainly was. Obviously I could never have afforded his auction and I think it went for around £1400, but I emailed him back to ask if he had anything I could add to the site history wise. This is what he sent me, and for the life of me I can't remember why I didn't add it straight away!

I can certainly drone on about Arthur and RISC OS ...

I was in charge of Acornsoft's languages group for the BBC when one day the
Technical Director - Jim Meriman - called me up and said "Can you and your chaps write
us a BBC-like Operating System for the ARM - you've got five months".

This was because the team in Acorn's Palo-Alto Research centre who had been
writing a super multi-threading all-singing all-dancing OS called ARX were running a
bit late. In fact they had just anounced it would be at least 18 months before it was ready.
As the ARM based machines were in design at the time and expected in 5
months this was a problem as you might imagine!

I of course said "yes" and so Arthur - which stands for "ARM on thursday" -
contrary to what I have seen elsewhere - was born.

We started off with ARM second processor boards hooked up to Beebs for I/O -
then got given extended second processor cards with their own I/O also hooked up to Beebs
and gradually got the video drivers etc going on these.

Then came the A500. These started off fed from the beeb via a tube "podule"
and we eventually made it self-supporting.- and the machine I have is the
first one to ever run Arthur without the umbilical to the Beeb.

I remember a very very late night when we could not get the keyboard
interface to talk to us. The spec said "send FF, then FF, then FE then FD" to get it out of reset...
Would this work... not a chance.
We were there with Brian Cockburn operating the logic analyser, Tony
Thompson on the source, Stuart Swales helping, and myself (in charge and
making tea) - eventualy out of frustration I said "oh just send it "F0" and
then see what it does... "F0" you understand being a rude suggestion! - And
blow me - The thing responded FF... and went though the right sequence.

And it was released like that... So, the very first thing RISC OS says to
the keyboard is "F0" :-)

Anyway, we make Arthur, with Relocatable Modules (which are a bit like BBC
roms), Basic, Filesystems, Graphics, etc and it was very good at being a
BBC - but by the time we had done it, ARX was no nearer - in fact it was
still 18 months away! So, we added a window manager, and a font manager to
arthur, and produced a desktop demo to prove what the machine could really
do.

There was then a week when "presentations" were made by the ARX team of the
state of their solution - they flew in from the US and demoed a multitasking window manager - they
only had one application - a clock. They ran it and then ran a second and a
third...At this point it started "thrashing" the hard disc on their 4M-RAM
machine because it had used up all the memory. The boys from Palo Alto said
"Ah yes well the thing is "Arthur" will not be able to do this at all -
because it's not multitasking"....

A few days later we (Arthur) demoed a 305 machine with half a meg, running
the desktop and we had a calculator and a clock - infact we fired up 12
copies of the clock....and they all ticked.

The next we heard ARX was cancelled, and Arthur was no longer the interim
solution. It became the mainstay of Acorn's existance, and after version 1.8
it was re-named RISC OS.

The Arthur Team were :-
Paul Fellows (I2C, Clock, Palette control, and Team leader)
Tony Thompson (OS core)
Stuart Swales (FileSwitch)
Richard Manby (Graphics)
Neil Raine (Window Manager, Fonts)
Nick Reeves  (ADFS)
Tim Dobson (Text printing, Serial & the rest of the I/O)
Brian Cockburn (Networking)

Assisted by (software)
Hugo Tyson (ADFS)
Dave Flynn (Sound)
Sophie Wilson (BASIC)
Martin Clemoes (Floating Point Emulator)

Not to mention the hardware chaps - - but then our names are in the ROM....