Editing Acorn R140

{{Infobox computer
| name         = Acorn R140
| image        = [[File:Acorn R140.jpg|260px|frameless]]
| caption      = An R140 running RISC OS, with its PC-style keyboard (photo: Chris Whytehead, CC BY-SA 3.0)
| manufacturer = Acorn Computers
| type         = Unix workstation
| release_date = 1989
| price        = £3,949 ex VAT with Ethernet; £3,500 ex VAT without (June 1989)
| cpu          = ARM2 (4/8 MHz)
| memory       = 4 MB (32 KB MEMC pages)
| rom          = 512 KB (RISC OS 2)
| storage      = 60 MB (unformatted) ST506 hard disc; 3.5-inch floppy drive, 800 KB formatted
| display      = Up to 1152 × 900 monochrome; 640 × 480 in 16 colours from 4096
| os           = RISC iX (4.3BSD Unix), booted from RISC OS 2
| power        = 198 to 264 V AC, 70 VA
| model        = UNX01 (base system); UNX01/AKA25 (with Ethernet)
| successor    = [[Acorn R260]]
}}
<templatestyles src="Template:StyledTable/styles.css" />
The '''Acorn R140''' is Acorn Computers' first Unix workstation, sold from early 1989.<ref name="wpriscix">[https://en.wikipedia.org/wiki/RISC_iX "RISC iX"], Wikipedia (retrieved 2026-10-02). Sections "Distribution" (installation by Granada Microcare from tape; RISC iX 1.2 upgrades from £349 for R140 machines; backup of the core system to three floppy discs), "Hardware" (R140 based on the A440/1; 1990 discount bundle at £2,999 plus VAT; an A440/1 with 4 MB and a suitable disc can run RISC iX) and "Legacy".</ref> It runs RISC iX, Acorn's port of Berkeley 4.3 Unix with System V extensions and the X Window System, on the hardware of the [[Acorn Archimedes A440|Archimedes 440/1]]: an ARM2, 4 MB of RAM, a 60 MB ST506 hard disc and a 3.5-inch floppy drive.<ref name="app214">Acorn Computers, ''Acorn R140 Workstation in Commercial and Technical Applications'', leaflet APP 214, first edition, January 1989. Hosted on this wiki: [[:File:Acorn R140 Workstation leaflet (APP214).pdf]]. RISC iX features, standard hardware, keyboard and mouse, interfaces, display monitor support, hardware expansion options, standard software and documentation.</ref><ref name="sm">Acorn Computers, ''400/1 & R140 Service Manual'', part no. 0483,075, issue 1, July 1989. Hosted on this wiki: [[Acorn A400-1 and R140 Service Manual]]. About this manual p. 5; technical specification p. 7 (RAM by model, ROM options, power inlet and outlet); functional testing p. 26 (an R140 is recognised as an A440/1); hard disc drive tests p. 27.</ref> RISC OS 2 in ROM starts the machine and then loads RISC iX from the hard disc.<ref name="chrisr">Whytehead, Chris. [https://chrisacorns.computinghistory.org.uk/RISCiXComputers.html "RISC iX Computers"], Chris's Acorns, The Centre for Computing History (retrieved 2026-10-02). R140: early machines based on a slightly adapted A440 and later ones on the A440/1; RISC OS 2 in ROM used only to boot the disc-based RISC iX; R140 £3,500 without monitor against £2,299 for the A440; the three RISC iX recovery floppies (one ADFS, two UFS); his upgraded R140 (Acorn Universal board 283,000 issue 2, backplane 0283,040 issue 3, serial 27-KB40-101mmm).</ref>

The R140 uses the main board, case and power supply of the Archimedes 400/1 series (the first R140s were built on a slightly adapted A440), and Acorn serviced both from one manual.<ref name="chrisr" /><ref name="sm" /> The board-level procedures are in the [[Acorn Archimedes 400/1 Series Maintenance Guide]], [[Acorn Archimedes 400/1 Series Troubleshooting Guide]] and [[Acorn Archimedes 400/1 Series Capacitor Guide]]; the sections below cover what is particular to the R140.

== History ==

Acorn's January 1989 leaflet describes the R140 as "the first in a series of personal workstations running the UNIX operating system".<ref name="app214" /> By June 1989 Acorn listed the workstation with Ethernet (UNX01/AKA25) at £3,949 ex VAT and the base system without the Ethernet card (UNX01) at £3,500, with twelve months' on-site maintenance included.<ref name="app221">Acorn Computers, ''R140 Computer Systems'', leaflet APP221, third edition, June 1989. Hosted on this wiki: [[:File:Acorn R140 Computer Systems price list (APP221).pdf]]. Descriptions and prices of UNX01/AKA25, UNX01, AKA20, AKA25, AKA30, AKA42, ADF10, SPX02 to SPX04 and UNX02.</ref> Chris Whytehead compares this with £2,299 ex VAT for the A440 at its launch, and records that the first R140s were built on a slightly adapted A440 and later ones on the A440/1.<ref name="chrisr" />

Wikipedia records a 1990 offer bundling the R140 with Ethernet and a monitor at £2,999 ex VAT, an upgrade to RISC iX 1.2 for R140 owners from £349, and the ARM3-based [[Acorn R260]] and [[Acorn R225]] that followed in 1990.<ref name="wpriscix" /> The [[Acorn A680]] was the earlier, unreleased RISC iX development machine.<ref name="chrisr" />

== Specification ==

{| class="wikitable styled-table" style="width:70%; text-align:left;"
|+'''R140 specification (Acorn leaflets APP214 and APP221, service manual)'''
! Item !! Specification
|-
| Processor || ARM 32-bit RISC processor; the service manual gives 4/8 MHz and typically 4 MIPS for the 400/1 and R140
|-
| Memory || 4 MB RAM, 32 KB pages; 512 KB ROM
|-
| Storage || 60 MB (unformatted) ST506 hard disc; 1 MB (unformatted) 3.5-inch floppy drive; a second external Winchester can use the internal ST506 controller
|-
| Expansion || Four expansion card slots (three free on the Ethernet model); internal Econet module that does not use a slot
|-
| Keyboard and mouse || 103-key "enhanced PC" style keyboard; three-button mouse
|-
| Interfaces || Serial, parallel; Ethernet and thin Ethernet (Cheapernet) on the AKA25 card
|-
| Display || 1152 × 900 monochrome (144 × 45 or 96 × 32 characters); 640 × 480 colour, grey-scale or monochrome with 16 colours from 4096
|-
| Software || RISC iX (4.3BSD with SVID extensions, two-user licence), ANSI C compiler, X11 release 2 with awm, twm and uwm, X.desktop, NFS 3.2 and Yellow Pages, RISC OS, and MS-DOS through the PC Emulator
|}

Sources: leaflets APP214 and APP221; processor figures from the service manual's technical specification.<ref name="app214" /><ref name="app221" /><ref name="sm" />

{| class="wikitable styled-table" style="width:100%; text-align:left;"
|+'''R140 options (APP221, June 1989; prices ex VAT)'''
! Code !! Option !! Price
|-
| AKA20 || Floating point expansion card with a WE32206 co-processor || £599
|-
| AKA25 || Ethernet expansion card, thick and thin (Cheapernet) Ethernet || £449
|-
| AKA30 || SCSI adapter card, up to seven devices || £299
|-
| AKA42 || PC Emulator || £99
|-
| ADF10 || Econet module || £49
|}

== Hardware ==

[[File:Acorn R140 with top cover removed.jpg|thumb|right|300px|An R140 with the top cover removed. This machine has been upgraded with an ARM3, an IDE card and an Atomwide Ethernet card (photo: Chris Whytehead, CC BY-SA 3.0)]]

The main board is the Acorn Universal Board used in the 400/1 series. Chris Whytehead's R140 carries board 283,000 issue 2 on the four-slot backplane 0283,040, the same backplane as the A410, A440 and A680.<ref name="chrisr" /> Acorn's service manual gives the R140's memory as 4 MB with a 32 KB page size, the same as the A440/1, and its functional test disc reports an R140 as an A440/1.<ref name="sm" />

The differences from an A440/1 are in what Acorn fitted and supplied: the 60 MB hard disc, the 103-key PC-style keyboard, the three-button mouse, the Ethernet card on the UNX01/AKA25 model and the RISC iX software.<ref name="app214" /><ref name="app221" /> Wikipedia notes that an A440/1 with 4 MB and a suitable hard disc can also run RISC iX.<ref name="wpriscix" />

=== Rear panel ===

Acorn's operations guide lists these connections on the back of the system unit:<ref name="ops">Acorn Computers, ''R140 Operations Guide'', part no. 0483,710, issue 1, December 1988. Hosted on this wiki: [[Acorn R140 Documentation]]. Mains plug fuse (p. iii); level zero dump backup (p. 32); close-down commands (p. 45); system unit description (pp. 49 to 51); cleaning (p. 75); replacing the batteries (pp. 78 to 80); changing the fan filter (pp. 81 and 82); if something goes wrong (pp. 83 to 89).</ref>

* Mono and Sync sockets for a high-resolution monochrome monitor; with a low-resolution monitor the Mono socket carries the whole signal.
* Analogue RGB socket, not suitable for TTL RGB monitors.
* Serial port and parallel printer port.
* Headphone socket for a 3.5 mm stereo jack, mainly for RISC OS.
* An Econet socket, blanked off if the Econet module is not fitted.
* Four expansion card positions behind the blanking panel, for four single or two double cards, and the Ethernet card where fitted.
* Mains input, mains output for a monitor, and the rocker on/off switch.

The 400/1 manual rates the unswitched mains outlet at 3 A continuous and the inlet at 70 VA.<ref name="sm" />

== RISC iX ==

RISC OS 2 starts first. RISC iX can then be booted from the RISC OS desktop or set to start automatically; <code>halt -RISCOS</code>, typed as root, closes RISC iX down and returns to the RISC OS command line or desktop.<ref name="ops" /> Close RISC iX down properly before switching off. To stop the machine from RISC OS, use <code>*Shutdown</code>, which also parks the hard disc heads.<ref name="ops" />

Acorn recommended a level zero <code>dump</code> backup of the filesystem as soon as the system was installed.<ref name="ops" /> RISC iX was supplied pre-installed or installed on site from tape by Granada Microcare, and the core system could be backed up to three floppy discs.<ref name="wpriscix" /> Chris Whytehead restored a minimal RISC iX to his R140 from the three recovery floppies (one ADFS, two in the Unix UFS format), but a full installation also needs a tar archive of RISC iX 1.15 on media the machine can read.<ref name="chrisr" />

Warning: Acorn's dealer test disc includes a hard disc formatter, verifier and soak test. Running these tests destroys the data on the disc, which on an R140 means the RISC iX installation.<ref name="sm" /> Back up the disc before running them.

== Maintenance ==

The general procedures for the board, power supply, drives and expansion cards are in the [[Acorn Archimedes 400/1 Series Maintenance Guide]]. Acorn's operations guide adds these R140 user tasks.<ref name="ops" />

=== Backup batteries ===

Two AA (LR6) alkaline cells in a battery nest power the clock and the configuration memory. Acorn's guide says to change them once a year.<ref name="ops" /> Old cells leak and corrode the holder and board; see [[Battery Explosion, Capacitor or Corrosion Damage]] and the battery section of the [[Acorn Archimedes 400/1 Series Maintenance Guide|400/1 maintenance guide]].

# Log in as root, close RISC iX down with <code>halt -RISCOS</code>, type <code>*STATUS</code> and write down the configuration, which will be lost.
# Type <code>*Shutdown</code> to park the hard disc, then switch off and unplug.
# Remove the three screws at the top of the back panel and the screws on each side, then slide the top cover back far enough to expose the front half of the machine.
# The battery nest is at the front right-hand corner as seen from the back. Leave its flying lead to the main board connected. Fit the new cells the right way round; the nest will accept them reversed.
# Refit the cover, hold down R while switching on to reset the configuration to factory settings, then use <code>*STATUS</code> and <code>*CONFIGURE</code> to restore the settings you noted. Reset the date and time.<ref name="ops" />

=== Fan filter ===

The cooling fan has a filter beside the battery nest, held by a clamp and two M4 nuts. Acorn's guide says to change it about once a year; the replacement filter is Acorn part 0276,034. Make sure the nuts go back in the right positions and are tight.<ref name="ops" />

=== Cleaning ===

Clean the case with a soft, slightly damp cloth. To clean the mouse, remove the ball retainer screw, clean the three rollers with a swab moistened with tape head cleaner, and wipe the ball with a dry, lint-free cloth.<ref name="ops" />

The moulded mains plug takes a 5 A fuse.<ref name="ops" />

== Fault finding ==

Hardware faults are diagnosed as for the 400/1 series, using the [[Acorn Archimedes 400/1 Series Troubleshooting Guide]] and the hosted service manual. The operations guide covers what a user sees first:<ref name="ops" />

{| class="wikitable styled-table" style="width:100%; text-align:left;"
|+'''R140 start-up problems (operations guide pp. 83 to 87)'''
! Symptom !! Probable cause !! Action
|-
| Nothing happens at power on, no power or hard disc light || Mains supply or plug fuse; cables || Check the outlet and the 5 A plug fuse; reconnect each cable<ref name="ops" />
|-
| Power and keyboard lights on, nothing on the screen || Monitor cable, adjustment or monitor; for a low-resolution text-only monitor, the internal links may not have been set || Check the cables and brightness; check the monitor type and the links<ref name="ops" />
|-
| Fuzzy or jumpy picture || Monitor type configured wrongly; alignment; loose signal cable || Check the configured monitor type, then the monitor's own adjustments<ref name="ops" />
|-
| Powers on, then nothing happens || Monitor, or corrupted CMOS RAM settings || Check that the H/DISC light flashes intermittently; see the RISC iX System Administrator's Manual for the CMOS settings<ref name="ops" />
|-
| RISC iX starts to boot but stops before the login: prompt || A one-off error, or a corrupted filesystem if it happens again || Restart; if it persists, Acorn says the filesystem is likely to be corrupted<ref name="ops" />
|-
| Shuts down without warning || Remote shutdown, a failed power supply or a blown plug fuse || Restart; if it will not start again, check the fuse and the supply<ref name="ops" />
|}

== Documentation ==

* [[Acorn R140 Documentation]]: the R140 Operations Guide (0483,710) and Acorn's APP214 and APP221 leaflets.
* [[Acorn A400-1 and R140 Service Manual]]: part 0483,075, issue 1, July 1989, the dealer service manual for the 400/1 series and the R140.
* Personal Computer World reviewed the R140 in March 1989; Chris's Acorns has the scan.<ref name="chrisr" />

== Gallery ==

<gallery mode="packed" heights="200">
File:Acorn R140 main board.jpg|Main board: the Acorn Universal Board 283,000 issue 2, as in the 400/1 series
</gallery>

== Related pages ==

* [[Acorn Archimedes A440]], whose 400/1 version the R140 is built on
* [[Acorn Archimedes 400/1 Series Maintenance Guide]]
* [[Acorn Archimedes 400/1 Series Troubleshooting Guide]]
* [[Acorn Archimedes 400/1 Series Capacitor Guide]]
* [[Acorn R260]] and [[Acorn R225]], the ARM3 RISC iX workstations
* [[Acorn A680]]

== References ==

<references />

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[[Category:Acorn Computers]]