The Acorn Cambridge Workstation was the only model from the announced, marketed but unreleased ABC (Acorn Business Computer) line, first claimed to be available in October 1984. The ABCs were a range of machines using an integrated monitor, disk drive, PSU and BBC B+ 64K motherboard with slight modifications, originally featuring CPUs from straight 6502 terminals to an 80286 based system.
Differences between the released Cambridge Workstation and the 32016 co-processor and ABC models were minor. Instead of the ABC 200 series' 512K or 1024K RAM, the Cambridge had 4096K, and a 20 MB HD instead of 10 MB. The Tube-connected board is very different from the 32016 co-processor, which also featured 1024K RAM. Internally the I/O board (a modified BBC B+) differed from a regular B+ in that the Econet system was fitted, the RF modulator was omitted, as was the sideways RAM expansion header and the header for the PHROM socket on the B's keyboard. The underside connections were upright instead of flat, but fully-featured.
Connected to the 1MHz bus internally were a mouse board (optional) with 2 connectors, one leading to a space for a further option (such as an internal modem), one leading to the SCSI controller which appears to be electronically identical to the internal modem-slot SCSI of the BBC Master Domesday machine. The SCSI controller was connected to an Adaptec MFM controller and a 20 MB hard disk.
The Tube connector wasn’t replicated externally, and linked to the 32016. A switch on the machine's keyboard allowed the Cambridge to run as a BBC B+ (the ROM identifies itself as a Cambridge Workstation with ADFS, then boots into BASIC without announcing it - OS is 2.10, same as a B+). Switching modes is destructive, rebooting the machine. As the BBC B+ handles all I/O, it is a slight bottleneck to the 32016, however for the time it was still an impressively fast computer.
The internal construction is very interesting. The monitor case has overcenter catches and lifts off (with some delicacy), revealing the display and not much else. Each side has a board carrier, one containing the 32016 and RAM, the other containing 1MHz bus devices. Once these are detached, 4 more catches release the monitor and it hinges up and forward, revealing the BBC B+ "I/O board". There are sockets for Speech (I have installed this option) and sideways ROMs - in theory any expansion for a B+ would work provided there is clearance. There is a volume control, explaining the connectors that are unused on the B+, and the keyboard's 25 pin (not fully populated) D-sub connector has a wire stripped off and directed to the co-processor board, but is otherwise electronically identical to a BBC keyboard!
The Cambridge was a dead-end for Acorn. Olivetti killed the project when they took over, though at least one exists with an ARM1 co-processor installed (perhaps user-added, but rumoured to be a real Acorn development machine). It's clearly an unfinished machine, and PANOS was yet another dead end, utilised seemingly because the intended OS - Xenix - required an MMU which the 32016 family lacked. It wasn't the only deviation from the widely-held belief that Acorn ignored CPUs other than the 6502 until the Archimedes range was launched, as the Acorn Communicator (another dead end, the case of which would later become the Master Compact) used the 65C815 16-bit CPU and the Master 512 used the 80186. Had Acorn released the ABC range it would have been too late to secure the marketplace for the apparent cost of constructing them, and the Cambridge, without any real OS or applications support, survived as a machine purely for academic use - offering remarkable computing power for the era and allowing students to compile their programs without having to time-share on a mainframe. The potential would have been enormous had it been marketed with a GUI at a time when the Macintosh could only muster 128 or 512K with no colour support...
Thanks A LOT to Richard Kilpatrick for all this info and pictures! Contact him if you are a user of this system, or have manuals, OS disks, software or anything related to it.
ABC 210 / Cambridge Workstation
END OF PRODUCTION
mid 1985, never reached full production
BUILT IN LANGUAGE
BBC Basic, Pandora (BIOS)
Standard QWERTY, 10 function keys + arrows, plus numeric keypad and Tube switch
4,6,8,10MHz (depending on source)?
MOS 65C02 (I/O board, essentially a BBC B+)
64K + 4096K
Taken from main RAM, up to 44K?
80 x 32/25 (2 colors) / 40 x 32/25 (2 or 4 colors) / 20 x 32 (16 colors) / 40 x 25 (Teletext display)
640 x 256 (2 colors) / 320 x 256 (4 colors) / 160 x 256 (16 colors)