This website is an archived copy of "Chris's Acorns", now hosted by The Centre for Computing History as part of The Chris Whytehead collection.
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RISCiX Computers

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 RISC iX computers

Details of RISCiX can be found HERE .


A development computer for RISC iX. Apparently only 2 were built and one was subsequently destroyed. I have never seen one. [Wanted] 


The A680 Technical Publishing System was developed by Acorn for Olivetti in 1988. Although it runs RISCiX, it seems to have been the original development machine as it's architecture differs from the Archimedes (e.g. there is no RISC OS component and the maximum RAM is 8MB). In May 2005 I bought an A680 on ebay from Adrian Godwin, Here is his description of the A680:

 Acorn A680 Technical Publishing System

This machine was built by Acorn in 1988 as one of the prototypes for a desktop publishing system to be sold by Olivetti. The system was never put into production so the remaining prototypes are very hard to find. This is thought to be the first to appear on eBay, though one or two have been sold on Usenet.

The A680 runs a variant of BSD 4.3 Unix called RISCiX : although the A680 was the first machine built to run RISCiX, it was used to develop versions later released on machines similar to the Archimedes series - the R140, R260 and R225. However, the A680 had substantially different (and more expensive) hardware than those machines with many built-in features that were options on the later models. It was therefore in use at Acorn long after the R140 was complete and didn't become obsolete until spare R260s were available.

The auction is for an A680 (serial number 147) in working order and fitted with SCSI, Ethernet and Laser Printer interface podules. These are in addition to the on-board SCSI interface intended for an external scanner. The Laser Printer (lbp) podule is especially rare as most A680s used for development purposes had these removed. A keyboard and mouse are included.

Also included is the hardware technical reference manual - about 250 pages with schematics of the main board and podules together with a great deal of technical information about the operation of the system. Parts of this TRM (such as the description of the podule bus) became the developer's reference for the entire Archimedes line. [I plan to scan the TRM and make it available in the documents section in PDF form, but scanning, OCRing andconverting to PDF format will take some time].

Some other peripherals which are not original but may be useful in setting up a complete, working system can also be included if the buyer wishes.

Because the machine was used as a desktop machine for some time both at Acorn and privately, it has had some modifications and wear and is not exactly as it would have been first built. As far as I am aware, these are limited to the following minor differences. Most can easily be restored.

The A680 was intended to use a high-resolution mono display (and could also be persuaded to use a low-resolution 15kHz mono display). I don't have a working hi-res display, but a modern multisync monitor will work : I have successfully tested it using an Eizo F56 connected only to the standard monochrome video connectors with some suitable BNC cables. [I have found that the A680 works quite happily with an Acorn AFK90 with only the green colour connected]

Here is the Acorn Technical Publishing System Technical Reference Manual Part 1
Here is the Acorn Technical Publishing System Technical Reference Manual Part 2
Here is the Acorn Technical Publishing System Technical Reference Manual Part 3 (technical drawings) 
Also Acorn Technical Publishing System User Guide [Wanted]
Acorn Technical Publishing System Programmer's Reference Manual [Wanted]
Acorn Technical Publishing System Service Manual [Wanted ]

 Here are some pictures of the A680:

 A680 running RISCiXA680 running RISCiX and X windows

 A680 in single user modeA680 in single user mode

 A680 frontA680 case front

 A680 backA680 case back

 A680 bottomA680 case bottom

 A680 with cover offA680 with top cover removed

 A680 showing podulesA680 showing podules

 A680 without podulesA680 with podules removed

 A680 motherboard topA680 motherboard top

 A680 motherboard bottomA680 motherboard bottom

 A680 backplaneA680 backplane

 Acorn AKA30 SCSI interfaceAcorn AKA30 SCSI card

 Acorn Lance Ethernet poduleAcorn Lance Ethernet card

 Acorn laserprinter cardAcorn Laser Printer podule



Serial No.01-A680B-0000147
Motherboard & part no. A680 Main PCB
0174,000 issue 1
s/n 0000112
CPU TypeWatford Electronics ARM3
CPU Modeln/a
CPU Clock25MHz
Memory controller2 x MEMC1a
Video ControllerVIDC1a
Floppy Disc Make & ModelSony MP-F17W-60D
Hard Disc ControllerOn board SCSI
Hard Disk Make & ModelConner CP30100
BackplaneAcorn A410. 440, 680
Backplane part no.0283,040
RISC OS version & daten/a
RISC iX version1.21c
7 Sep 1993 (A680)
Podules0. Acorn "Lance" Ethernet
1. Acorn Laser Printer
3. Acorn AKA30 SCSI
!SICK v1.22 
PSUASTEC Model SA 120-3405
S/N 007116050 DATE 8730
120W MAX
Dimensions (W x D x H)480 x 385 x 110 cm



Having successfully released the Archimedes range in 1987, Acorn turned to a different operating system for their next machine. The machine was the R140, (R140 Specification ) and was launched in September 1998. Initial machines were based on a slightly adapted A440, later machines were based on the A440/1. It featured the same ARM2 and 4 Mb of memory, but had a larger 60 Mb ST506 hard drive. Although it had RISC OS 2 in ROM, this was only used for the inital boot process which then loaded the disc-based RISC iX UNIX system, The R140 was aimed at the low end of the UNIX workstation market.

When the Archimedes range was launched the top of the range A440 without monitor cost £2299 exVAT. The R140 without a monitor cost £3500, the AKA25 Ethernet podule cost £599 ex VAT and an AKA30 SCSI adapter cost £299

 APP215 R140Here is the Acorn product brochure for the R140
Acorn APP221 R140Here is the R140 product specification and price list.

Here is the Archimedes 400/1 and Acorn R140 Service Manual. 

In March 1989 PCW pubished a review of the R140 titled "Acorn R140".

When the R140 was launched, it was very similar to the A440, but my R140 has been "upgraded" substantially. The CPU was an ARM2, but has upgraded to an IFEL 36MHz ARM3. The MEMC1 has been upgraded to MEMC1a. The original hard disc was missing and had been replaced by the Risc Developments IDEFS card. But you cannot install RISC iX on an IDE drive, so I found and installed an old ST506 Kalok KL320 drive (which is listed in Acorn documentation as used on the A400 series). The Atomwide Ethernet IV card is not original. The Operating System has been upgraded from RISC OS 2 to RISC OS 3.10.

I bought my R140 in September 2001 on ebay. It was one of the first items I bought in an online auction. I have attempted to re-install RISC iX on the R140 using the Recovery discs. These are a set of 3 floppy discs, 1 in ADFS format and the other 2 formatted in UFS format which can only be read by RISC iX, which enable you to restore a minimal RISC iX system to an R140. I was successful! But to restore the full RISC iX system I need a tar archive of RISC iX v1.15 on media I can read (i.e. RISC iX formatted floppy disc) without this I am stuck,

 Here are some pictures:

 R140R140 running RISC OS

 RISC iX boot!RISCiXFS ready to boot RISC iX

 RISC iX bootingRISC iX kernel loading

 RISC iX loadedRISC iX 1.15 loaded

 R140 OpenR140 with top off

 R140 insideR140 motherboard

 R140 BackplaneR140 Backplane


Serial No.27-KB40-101mmm
Motherboard & part no. Acorn Universal board
283,000 Issue 2
CPU ModelVY86C020-35PSGC
CPU Clock36MHz
Memory controllerMEMC1a
Video ControllerVIDC1a
Floppy Disc Make & ModelCitizen OSDC-65A
Hard Disc ControllerOn board ST506
Hard Disk Make & ModelKalok Octogon KL320
BackplaneAcorn A410. 440, 680
Backplane part no.0283,040 Issue 3
RISC OS version & dateRISC OS 3.10
RISC iX version1.15 
Podules1. Risc development IDEFS + IBM 540MB HD
2. Atomwide Ethernet IV
!SICK v1.22 
Mode 15



The R225 is as discless workstation, a variant of the R260, and was released in June 1990. Because it was discless, RISC IX had to be installed on a fileserver by Grenada Microcare. Alternatively a single R225 could be booted and run from a networked R260.
The following product was produced:

 I haven't seen one. [Wanted] 


The R260 is functionally identical to the A540. The R260 was fitted with 8 Mb of RAM and a 100 Mb SCSI hard disc drive as standard, while the R225 came with 4 Mb of RAM and no hard drive, and was intended as a cheap networked UNIX workstation. Both machines were supplied with ARM3 chips and built-in Ethernet interfaces.

Here is the Acorn R260 product brochure.

In August 1990 Personal Computer World published a review titled "Acorn R260 "

Here is the R260, R225, A540 installation Guide .

Here is the Archimedes 500 and Acorn R200 Service Manual .

The following product was produced:

I bought my R260 on Yahoo in February 2002. Unfortunately the RISC iX partition got corrupted, I think due to disc faults, but possibly my ignorance and I no longer have a copy of RISC iX 1.2 running on it. So if anyone can clone a disc with RISC iX on for me, please get in touch.
Here are some photographs.


 R260 openR260 Open

 R260 MotherboardR260 motherboard

 R260 CPU & MemoryR260 CPU & memory cards


Serial Number01-UNX26-1000012
Mothrboard & part No.0186,000 Issue 1
CPU Clock30MHz
Memory controllerMEMC1a
Video controllerVIDC1a
Floppy Disc make & model Citizen OSDC-65C
Hard Disc controllerSCSI
Hard Disc make & ModelConnor CP3100 100MB
BackplaneAcorn 4 slot
Backplane part No.0186,001 Issue 1
RISC OS version & date2.01
RISC iX versionn/a (was 1.2 but see above:-( )
PodulesAcorn AKA25 Ethernet Expansion
Acorn AKA31 SCSI Podule
!SICK v1.22
Mode 15

With the 30 MHz ARM3 CPU replaced by a 25MHz ARM3 with an FPA10 installed, the Dhrystones/sec fell to 22,621, but the kWhetstones/sec rose to 2807. This shows that an FPA10 makes a signifcant improvement to applications with floating pooint code (e.g. RISC iX).

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