Clive Sinclair has a lot to answer for :) One of his long-term
employees at Sinclair Radionics was one Chris Curry, who started Science of
Cambridge for Clive and was a part of the small team who built the MK14 (one
of the very first cheap home kit computers at £39.95) and the Sinclair
wrist calculator. He wanted to expand the MK14 to have a BASIC interpreter and TV connection but
Clive didn't since he was already pursuing the design of the Newbrain, so they parted company and Chris set up Acorn with a Cambridge
University friend, Hermann Hauser.
The first machine they came up with was the System-1 in 1978,
a 6502 based single board computer (SBC) that ran BASIC. It became the basis
for their first 'real' machine, the Atom. Like most machines of the day aimed
at the hobbyist market the Atom came as a kit to be soldered at home and later
was available as an assembled system.
Next up came the concept of a machine called the Proton. It was
to be a 16K machine with enhanced BASIC, colour, sound and expandability, but
design issues meant it's development was stalled....also around this time the
UK Government were pushing their Computer Literacy for Schools campaign and
wanted a low-cost computer that could spearhead it; initially they were just
going with the Newbrain from
Newbury Labs, but production difficulties, a 2 year wait AND angry letters from
Chris Curry and Clive Sinclair forced them to rethink. Initially they hadn't
considered Sinclair and Acorn because they wanted a colour Z80 machine - the
ZX81 was monochrome and the Atom was 6502 based.
The Proton was now nicknamed the Beebon and a rushed system was
done in less than a week, and I have it on good authority that despite Fred
Harris using a Beebon in the first series of 'The Computer Programme' the machine
actually doing the work was a System 3 that sat under the desk :o)
Uncle Clive also got the Spectrum out the door faster than he
should've done to go against the BBC, but the keyboard and lack of networking
meant the Beebon still won and became the BBC Micro.
Acorn nearly lost out again a couple of years later; they'd sat
on their laurels for too long when they should've been producing a followup
machine to the BBC, so while the next generation of Beebs was in development
they had to produce souped-up versions of the BBC Model B, resulting in a B+
64K and a B+ 128K before the BBC Master hit the streets in 1986.
The 'standard' Master featured 128K RAM, better sound capabilities,
enhanced BASIC, and several apps built in to the MOS ROM such as View, ViewSheet,
Terminal and the ADFS ROM for disk access ("A" for 'advanced' - though
disks written using ADFS weren't compatible with the DFS chip in the Model B).
Unfortunately there were also some compatability issues with earlier BBC B software,
but that didn't stop anyone; in the first 3 years of production over 200,000
Masters went out the factory.
Upgrades were produced too, a 512K RAM variant and the Turbo,
which featured a 65C02 co-processor - it was this machine that was used
for the Domesday System.
After this Acorn started developing their own CPUs, called ARM
(Acorn RISC Machine), and the first machines to get the new CPUs were the Archimedes
range, which started with the A305 and ended with the A7000+ in the mid-90s
after Acorn had quit home computing to concentrate on CPUs and embedded systems.
Cash problems had meant a brief marriage to Olivetti before finally giving up
the ghost. Castle Technology bought the rights to the Archimedes and RISC PC
range and still support them today.
*Update* - Courtesy of Gavin Saxby (originally) and Rich Kilpatrick I now have in my paws a
fully working Acorn Cambridge Workstation with a handful of disks and missing keyswitch. Yes folks, if you're googling for
ACW related stuff you'll find entries on the likes of old-computers.com....the machine I have is that machine :oD
*update 2* - a machine I didn't know existed until recently even though its story ended in 1998 with the closure of Acorn's Workstation division. The Phoebe 2100 or RiscPC2 never saw the light of day owing to overambition and flaws in its IOMD2 chip which I see as a ULA/ASIC thus nicely bringing back the ULA problems that dogged Acorn (and others) in the 80s. There's lots of writeups on Phoebe (yes, named after the 'Friends' character Phoebe Bouffet) already so I won't bother linking to them here. What I will show is the pictures of the machine at the Wakefield RiscOS show yesterday (13/05/06) on the Binary Dinosaurs stand courtesy of Andrew Whickham and Retrobeep at Bletchley Park. Link is in the menubar.
Oh, the machine we showed is this one.
System 1, unbuilt kit, CPU board only so I don't have
the keyboard or display card. Atom, original kit-built unit with schematic
and extra chips. Came with tapes and the world's largest domestic PSU :) Electron, fully boxed mint with all the manuals and
a load of games. Retail boxed Electron, mint but missing the cassette
leads. Nice cover! Electron on its own with attached Plus-1 extender.
Mint BBC-B with Cub monitor and Cumana disk drive. BBC-B with issue 3 board and a serial
number of less than 20,000. "Patent Pending" don'tcha know! Mostly boxed Beeb B with manual. Almost
mint condition too, from Bainbridges no less :) 64K BBC B+ (didn't know these existed!)
BBC Master 'Domesday' setup complete with LV-ROM drive,
trackball and Mouse. Second Domesday setup - Master AIV, Philips VP415 Laservision player, trackball and discs. Philips' demo unit #7! BBC Master 'Domesday' machine. BBC Enterprises unit #3, Issue 1 machine (12/85) with Cox 630B Genlock, used to create Domesday disc video content!
BBC Master boxed with option ROMS, disks and floppy drive
BBC Master Turbo with excellent condition dual Cumana floppy BBC Master boxed with floppy drive. BBC Master Compact x2 - 2 piece machine with
*gasp* 3 1/2 inch floppies. BBC B+ *box* from Lee, in new condition
:) Acorn Cambridge Workstation aka the ACW-210, working. Cheers Rich & Gavin!
Archimedes A3000 with monitor, rodent and some disks.
Archimedes A3010 with monitor and manuals, still with product 'wow look what this can do' flash stuck to it!
Archimedes A3020 with monitor, mouse and MIDI expansion unit. Archimedes A4000 with monitor, keyboard
and HP500 Deskjet printer. Archimedes A5000 with keyboard. A7000 with keyboard and monitor. Nice machine!
A7000+ from Russ Smith, working after a hardware reset. Thanks Russ!
Archimedes A310, boxed with boxed monitor and keyboard.
Archimedes A410/1 with monitor, keyboard, rodent etc
Prototype Archie A540 from Rich Kilpatrick. I know it's a prototype because it has 'prototype' stamped on it :) Unfortunately it's been 'parcelforced' so it's a bit bent.
RiscPC 640 on its own, don't know if it works yet.
6502 second processor for the B 32016 CoProcessor for the BBC Master Teletext adapter for the B with
ROMs and keyboard overlay. 'Advanced' teletext adapter for the B
Keyboard for the Archimedes 5000
BBC 5 1/4 Floppy Disk Drive
Opus floppy drive Electron Data Recorder, mint
with PSU and manual
Acorn Program recorder
BBC Program recorder
Cumana double 5 1/4 floppy for the beebs Plus-1 ROM extender for the Electron,
boxed perfect but missing manual Plus-3 3 1/2" floppy add-on for the Electron
Some sort of Music Synthesizer for the Beeb Ethernet modules for the Archimedes 3000 and
5000, boxed unused. Econet modules for the Beeb B.
Severalteen Electron games, boxed, some mint. "View" ROM cart for the Electron
Plus-1, not bad condition. Wizard Joystick interface and sideways
ROM board for the Electron in excellent nick.
Microvitec Touch Screen addon for the Cub monitors, courtesy of Rich Harding's
local tip :)
*rare* - 3 Master Compacts! *grin* Electron with Plus-1 and Plus-3
addons, er, added on.
Here's a potted history of the Archimedes range by Darren Northcott
and Matthias Siefert, now abridged by me:
As far as I'm aware the list of Archimedes machines went :
a500 (only 100 made), a305, a310, a410, a420, a440, a420/1, a440/1, a540,
a3000, a5000, A4 portable, a3010, a3020, a4000,
RiscPC, RPC600, RPC700, a7000, a7000+, RiscPCSA
Starting at the a305 with Arthur as the OS, with 512KB
RAM, 8Mhz ARM2 and a Single DD floppy drive.
The a310 was still Arthur, single DD floppy, but with 1MB
The 400 series first introduced RISCOS, the 2nd
digit in the number indicating the amount of RAM in MBs,
these machines had ST506 HDD interfaces built in, tho only
the 420 and 440 were sold with HDDs fitted.
The A440 (there was never really an A410 or A420 available) still was
running Arthur. In fact, the A305, A310 and A440 were introduced
(virtually) at the same time. These models were called "Archimedes",
i.e. "Archimedes 305", "Archimedes 310" and "Archimedes
After the A3xx and A440 there was the R140. This was a slightly
modified A440. It was running a (disc based) Unix system called
"RISC iX" (based on BSD 4.3).
After that, there was the A4xx/1 series (A410/1, A420/1 and A440/1).
The a4x0/1 machines fixed some design flaws on the 400
These were followed by the A3000 (replacing the A3xx series). This was
the first model fitted with RISC OS (V2.00) right from the start (but
the old models could be upgraded to RISC OS). The A3000 was the first
model not called "Archimedes" anymore (AFAIK Acorn had problems
producing the A3xx series which lead in a whole production run being
dumped, which went through the [UK] press - and Acorn feared that this
gave a bad reputation for the "Archimedes" computers).
Then there was the A540. It contained an ARM3 which was clocked at 26
MHz and was fitted with a SCSI interface and a 100 Mbyte SCSI
harddisc. It was shipped with RISC OS 2.01 (which only differece
to 2.00 was, that it was able to handle more than 4 Mbyte of RAM as the
A540 could have up to 16 Mbyte of RAM).
The a3000 used an ARM2 at 8MHz, but was designed to
be the 'entry level' games machine, RISCOS2, 1MB RAM,
single DD floppy.
After that, there was the R260 and R225 which were based on the A540
and replaced the R140. They were both fitted with an ARM3 at 26 MHz and
built-in Ethernet interfaces. The R260 was also fitted with a SCSI
interface, a 100 Mbyte SCSI harddisc and 8 Mbyte of RAM, whereas the
R225 was discless (even without SCSI interface, the RISC iX OS was
booted off from Network connections) and only had 4 Mbyte of RAM.
The a5000 was designed as a partial replacement for the
a540, the first version had RISCOS3.00, which had a couple
of VERY nasty bugs in the filesystem, the second release had
ROS3.10, which was followed by RISC OS
3.11 (and RISC OS 3.19 which simply was the German variant of RISC OS
3.11). The 5000 had a 25Mhz ARM3 CPU, 12MHz memory,
2MB RAM as standard, 4MB max, IDE HDD interface,
HD floppy drive, was sold in 4 models with either 40, 80, 120,
or 160 MB HDD.
The A4 was *supposed* to be the portable version of the a5000. 4MB RAM
was standard, 60 or 80MB HDD, 640x480 16greyscale LCD,
25MHz ARM3, RISC OS 3.11 (with a few extensions in a seperate ROM)..
The case was 'borrowed' from Olivetti (which held the majority of Acorn shares
that time). BTW: The A5000 was (according to people at Acorn) an A4 in
a desktop box (i.e. it was a spin off from the design of the A4) - and
not the other way round as one may expect.
The a3010, a3020 and a4000 were all released simultaneously,
all are based on the ARM250 CPU which was a single chip
implementation of the ARM2 CPU, VIDC video processor,
IOC and MEMC chips as found in the early 300 and 400
series machines. The CPU was clocked at 12MHz, the
a3010 was marketed as the games machine, it had a joystick
port as standard, and also had a TV modulator, 1MB RAM,
single HD floppy, no HDD, the a3020 had 2MB ram, came in
2 versions, one with no HDD, one with an 80MB HDD.
The a4000 looked like a cut down a5000, but actually had
almost the same motherboard as the a3020, available in 2
versions, 2MB ram 80MB HDD, or 4 MB ram 160MB HDD.
All used RISCOS3.10.
Then there was the A5000 (Alpha variant). It contained an ARM3 at
33 MHz and could be upgraded with a hardware floating point accelerator
The RISCPC was almost a completely new machine, it used
a 33MHz ARM6 CPU, 160MHz VIDC20, enhanced IDE,
new parallel and serial ports, and RISCOS3.5, typically
about twice as fast as the a5000 in CPU terms, and over
6 times faster with video intensive tasks, this was the first
acorn machine to support 'truecolour' as standard, it also
increased the expansion capabilities from 4 cards max in any
of the older machines to 8 podules, 1 network card and a
co-processor slot on the motherboard, the machine supported
upto 256MB of RAM via 2 72pin SIMM slots, and 2MB
of VRAM in another slot, the case design is modular, each
case 'slice' can take 1 5.25 inch drive and 1 3.5 inch drive,
plus each slice adds 2 expansion card slots to the base machine,
the 'base' machine has a single slice, containing the HD floppy
drive and two expansion slots, plus a free 5.25 inch bay.
The HDD sits in a slot under the first slice, original machines
were supplied with 2 or 4MB of ram, 260 or 480MB hdds
and 0 or 1MB of VRAM.
The RPC600 and 700 were improvements on the original RPC,
the 600 used an ARM 610 processor clocked at 33Mhz and shipped with RISC OS
The 700 used a 40MHz ARM7 in place of the ARM6, because of
internal CPU enhancements the 40MHZ ARM7 was almost
twice as fast as the 33MHz ARM6. It was possible to retrofit 16 bit sound hardware
into the 700.
The a7000 was a cheaper version of the RPC and a successor to the A4000. It
ARM7500 cell processor clocked at 32Mhz which contained the 4 main chips
of the RPC700 in a single package, it had a simple non
expandable case, and the design was such that you could have
'either' an internal CD, 'or' 2 internal expansion cards, but not
both. The early a7000 used RISCOS3.5, later a7000s with
16bit audio used RISCOS3.6.
After that there was the StrongARM RiscPC (with just "RiscPC" written
on its case). It was basically a RiscPC 700 with RISC OS 3.7 and a
StrongARM at 200 (in fact 202.7) MHz. (There never was a StrongARM
with 170 MHz used in a RiscPC.)
The a7000+ was an enhanced version of the a7000, it used
the ARM7500fe CPU which incorporated a maths chip,
the first ARM CPU to do so, the clock speed was 40MHz,
the memory bus was enhanced to allow faster rams to be
used, and EDO was fully supported. The A7000+ always was shipped
with RISC OS 3.71 (a variant of 3.7 with several bugfixes, which was
never available for any other machine).
Then there was the StrongARM RiscPC (Alpha variant). It was identical
to the previous StrongARM RiscPC but now contained a StrongARM with
233 (in fact 236.2) MHz. This machine was also sold under the name
"J233" which only difference was, that there was additional software
installed (including Java and a Webbrowser).
Then there was the RiscPC 700. This was basically a RiscPC 600 with an
ARM710 (at 40 MHz), 16 bit sound hardware and a slightly better VIDC20
(which made it possible to display slightly higher resolutions). It
was equipped with RISC OS 3.6.
Since the closure of Acorn in 1998, Castle technology has
taken over manufacture and sales of the a7000+ and RPCSA,
other companies have also started making RISCOS based
computers, RiscStation, MicroDigital, and others.
Development of RISCOS has been taken over by a new
company called RISCOS Ltd, however, prior to Acorns
closure Acorn sold the rights to RISCOS to PACE, as such
most of the recent developments in RISCOS were done by
PACE, and then released by RISCOS Ltd."