Editing Acorn Archimedes (section)

== Hardware ==

=== Graphical capabilities ===
The Archimedes machines (and their equivalents running [[RISC iX]]) used the [[VIDC1]]a video chip to provide a wide variety of screen resolutions, expanding on those available on the [[BBC Micro]], including the following:<ref name="acorn_app118_issue1">{{ cite book | url=http://chrisacorns.computinghistory.org.uk/docs/Acorn/Brochures/Acorn_APP118_ArchimedesJun87.pdf | title=Archimedes High Performance Computer Systems | publisher=Acorn Computers Limited | date=June 1987 | access-date=18 April 2021 | issue=1 | pages=12 }}</ref>

{| class="wikitable"
|-
! Resolution
! Colours
! Notes
|-
| 160 × 256
| 4, 16, 256
|
|-
| 320 × 256
| 2, 4, 16, 256
|
|-
| 640 × 256
| 2, 4, 16, 256
|
|-
| 640 × 512
| 2, 4, 16, 256
| [[Multisync monitor]] required
|}

Since the video controller would not support display modes smaller than 20&nbsp;KB, the lowest resolution modes were supported in the operating system by employing modes with twice the horizontal resolution and duplicating horizontally adjacent pixels.<ref name="acornuser198908_agora">{{ cite magazine | url=https://archive.org/details/AcornUser085-Aug89/page/n23/mode/2up | title=Screen Play | magazine=Acorn User | date=August 1989 | access-date=18 April 2021 | last1=Acton | first1=David | pages=22–23 }}</ref><ref group=note>The claimed 20&nbsp;KB limitation is actually a consequence of the minimum pixel clock frequency supported by the VIDC of 8&nbsp;MHz, together with the typical display frequencies of supported monitors, notably the horizontal sync frequency of 15&nbsp;kHz, and the colour depths of the defined modes.</ref>

The introduction of RISC OS brought support for a number of new display modes including the following:<ref name="a400_ug" />

{| class="wikitable"
|-
! Resolution
! Colours
! Notes
|-
| 640 × 480
| 2, 4, 16, 256
| Multisync or 60&nbsp;Hz VGA-type monitor required
|-
| 1056 × 256
| 16, 256
| 132-column modes
|}

The A540<ref name="acorn_app468"/> and A5000<ref name="acornuser199112_a5000"/> supported additional display modes:

{| class="wikitable"
|-
! Resolution
! Colours
|-
| 800 × 600
| 2, 4, 16
|}

High-resolution monochrome display modes were offered by the A440, A400/1 series and A540:

{| class="wikitable"
! Resolution
! Mode
! Availability
|-
| 1280 × 976
| 22
| A440 running the Arthur operating system,<ref name="a440_sm">{{ cite book | url=http://chrisacorns.computinghistory.org.uk/docs/Acorn/Manuals/A440_Service_Manual.pdf | title=Archimedes High Performance Computer Systems Model 440 Service Manual | publisher=Acorn Computers Limited | date=November 1988 | issue=1 | access-date=19 April 2021 | pages=8 }}</ref><ref name="acorn_app136">{{ cite book | url=http://chrisacorns.computinghistory.org.uk/docs/Acorn/Brochures/Acorn_APP136_Archimedes440Jan88.pdf | title=High Performance Computer Systems Archimedes 440 | publisher=Acorn Computers Limited | date=January 1988 | access-date=19 April 2021 | issue=1 | pages=4 }}</ref> this mode being dropped from RISC OS<ref name="acornuser198902_new_modes">{{ cite magazine | url=https://archive.org/details/AcornUser079-Feb89/page/n25/mode/1up | title=New modes for programmers | magazine=Acorn User | date=February 1989 | access-date=1 May 2021 | last1=Bell | first1=Graham | pages=24 }}</ref>
|-
| 1152 × 864
| 23
| A440 running Arthur,<ref name="a440_sm" /> A400/1 series running RISC OS,<ref name="a400_ug">{{ cite book | url=https://www.4corn.co.uk/archive/docs/Archimedes%20400%20Series%20User%20Guide-opt.pdf | title=Archimedes 400 Series User Guide | publisher=Acorn Computers Limited | date=1988 | edition=2 | issue=1 | isbn=1852500530 }}</ref>{{rp|pages=453}} A540<ref name="acorn_app301">{{ cite book | url=http://www.4corn.co.uk/archive/docs/AMPAPP/150/APP301%20(1st%20ed)%20-%20Archimedes%20540%20(1990)-opt.pdf | title=High Performance Computer Systems Archimedes 540 | publisher=Acorn Computers Limited | date=August 1990 | access-date=19 April 2021 | issue=1 | pages=6 }}</ref><ref group=note>Given as 1152 x 900 for A400/1 series and A540.</ref>
|}

Apparent confusion about monochrome monitor support upon the launch of the Archimedes models led Acorn to clarify that the A400 series had "extra circuitry" offering two additional display modes "of up to 1280 by 976 in monochrome, and 160 columns by 122 lines of text, but only using a special monitor",<ref name="acornuser198710_multitasking">{{ cite magazine | url=https://archive.org/details/AcornUser063-Oct87/page/n8/mode/1up | title=Multi-tasking for Archimedes | magazine=Acorn User | date=October 1987 | access-date=19 April 2021 | pages=7 }}</ref> this being connected using two BNC sockets (one for signal and one for sync).<ref name="a400_ug" />{{rp|pages=465}}

The A540 (and corresponding R-series workstations) offered three BNC sockets, adding one for a separate horizontal sync connection for certain monitors.<ref name="acorn_r260_inst">{{ cite book | url=http://chrisacorns.computinghistory.org.uk/docs/Acorn/Manuals/Acorn_R260R225A540InstG.pdf | title=Installation Guide | publisher=Acorn Computers Limited | date=July 1990 | issue=1 | isbn=1852500808 | access-date=19 April 2021 }}</ref>{{rp|pages=86}} Acorn suggested the 19-inch Taxan Viking and Philips M19P114 monitors,<ref name="acorn_r260_inst" />{{rp|pages=78}} with the former being offered in a bundle with the R140 workstation.<ref name="acornuser199002_r140">{{ cite magazine | url=https://archive.org/details/AcornUser091-Feb90/page/n8/mode/1up | title=Cheap Workstation | magazine=Acorn User | date=February 1990 | access-date=19 April 2021 | pages=7 }}</ref> The Taxan Viking R140 product bundled the existing Viking product with appropriate cabling and produced a "rock steady" 66&nbsp;Hz mode 23 display, albeit with mouse pointer corruption at the extreme right of the screen due to "a bug in the VIDC chip".<ref name="acornuser199003_monitors">{{ cite magazine | url=https://archive.org/details/AcornUser092-Mar90/page/n126/mode/1up | title=Screen Test | magazine=Acorn User | date=March 1990 | access-date=5 May 2021 | last1=Bell | first1=Graham | pages=125 }}</ref>

The A5000 unlike its predecessor, the A540, did not support high resolution monochrome modes.<ref name="app390">{{ cite book | url=http://chrisacorns.computinghistory.org.uk/docs/Acorn/Brochures/Acorn_APP390_A5000.pdf | title=Acorn A5000 The benefits of power | publisher=Acorn Computers Limited | date=November 1991 | access-date=19 April 2021 | issue=2 | pages=6 }}</ref>

==== Graphics expansions ====

An expansion to speed up the VIDC chip in the Archimedes from 24&nbsp;MHz to 36&nbsp;MHz was announced by Atomwide in 1990, offering higher resolution display modes for machines connected to multisync monitors.<ref name="acornuser199006_atomwide">{{ cite magazine | url=https://archive.org/details/AcornUser095-Jun90/page/n8/mode/1up | title=Atomwide Enhancers | magazine=Acorn User | date=June 1990 | access-date=10 May 2021 | pages=7 }}</ref> Although resolutions up to {{nowrap|1280 x 480}} and {{nowrap|1024 x 640}} were supported, flicker due to a decreased refresh rate was reported as a problem, with {{nowrap|1152 x 486}} appearing to be more comfortable in this regard. The SVGA resolution of {{nowrap|800 x 600}} was also supported in up to 16 colours.<ref name="riscuser199101_vidc">{{ cite magazine | url=https://archive.org/details/eu_RiscUser_1991-0102A_OCR/page/n29/mode/2up | title=Making the Most of Your Multi-Sync Monitor | magazine=RISC User | date=January 1991 | access-date=10 May 2021 | last1=Spencer | first1=David | last2=Thorpe | first2=Martin | pages=30–31 }}</ref> One side-effect of increasing the frequency of the VIDC was to also increase the frequency of generated sounds, since the VIDC was also responsible for sound generation.<ref name="archive199007_vidc">{{ cite magazine | url=https://archive.org/details/Archive_1990-07_OCR/page/n22/mode/1up | title=Atomwide VIDC Enhancer | magazine=Archive | date=July 1990 | access-date=10 May 2021 | last1=Ward | first1=John | pages=21–23 }}</ref> VIDC enhancers were supplied by some monitor vendors together with the appropriate cable for Archimedes machines, although fitting the device still required approved service work to be performed. Monitors such as the Taxan 795 Multivision were only usable in multisync modes without the VIDC enhancer whose accompanying software sought to "redefine all modes" to be compatible with the display as well as providing new modes.<ref name="acornuser199012_multivision">{{ cite magazine | url=https://archive.org/details/AcornUser101-Dec90/page/n120/mode/1up | title=Multivision Magic | magazine=Acorn User | date=December 1990 | access-date=12 May 2021 | last1=James | first1=Paul | pages=119 }}</ref>

One drawback of VIDC enhancer solutions was the increased memory bandwidth used by the VIDC at its newly elevated frequency, slowing down machines when using higher resolution modes, particularly machines with ARM2 processors and slower memory busses. Consequently, other solutions were adopted to work around the limitations of the built-in display hardware, notably "graphics enhancers" such as the PCATS graphics enhancer from The Serial Port,<ref name="acornuser199107_pcats">{{ cite magazine | url= https://archive.org/details/AcornUser108-Jul91/page/n104/mode/1up | title=Good Looking | magazine=Acorn User | date=July 1991 | access-date=15 May 2021 | last1=Williams | first1=Simon | pages=103 }}</ref> and "colour cards" such as Computer Concepts' ColourCard and State Machine's G8 which provided a separate framebuffer, holding a copy of the normal screen memory, for use in generating a video signal independently of the system's main memory. This permitted higher refresh rates (up to 70&nbsp;Hz) even for higher resolution modes, although the maximum size of the screen memory imposed by the VIDC ({{nowrap|480 KB}}) also imposed a limit on available resolutions and colour depths, with {{nowrap|800 x 600}} being the highest resolution 256 colour mode that could be supported. However, such cards were also able to support more flexible palettes in 256 colour modes than the VIDC, and for lower resolutions, greater colour depths offering over 32,000 colours could be supported.<ref name="acornuser199301_colourcards">{{ cite magazine | url=https://archive.org/details/AcornUser126-Jan93/page/n62/mode/1up | title=More than a shade better | magazine=Acorn User | date=January 1993 | access-date=3 March 2021 | last1=Bell | first1=Graham | pages=61–63 }}</ref> The ColourCard was reported to allow an ARM2 system to use a {{nowrap|1600 x 600}} display mode with 16 colours (occupying 480&nbsp;KB) with an operating speed of "160% of the speed of the considerably lower resolution Acorn mode 28", this being {{nowrap|640 x 480}} with 256 colours (occupying 300&nbsp;KB).<ref name="archimedean1993">{{ cite magazine | url=https://archive.org/details/Archimedean_Issue_7_1993_Computer_Concepts_GB/page/n9/mode/1up | title=ColourCard ...even better! | magazine=The Archimedean | date=1993 | access-date=19 May 2021 | pages=10 }}</ref>

State Machine, founded by former hardware designers from Computer Concepts and Watford Electronics,<ref name="acornuser199208_statemachine">{{ cite magazine | url=https://archive.org/details/AcornUser121-Aug92/page/n14/mode/1up | title=24-Bit Colour at BAU Show | magazine=Acorn User | date=August 1992 | access-date=8 February 2022 | pages=13 }}</ref> announced a range of colour card peripherals, starting with the G8 and G8+ in late 1992,<ref name="acornuser199210_statemachine">{{ cite magazine | url=https://archive.org/details/AcornUser123-Oct92/page/n18/mode/1up | title=New Card | magazine=Acorn User | date=October 1992 | access-date=3 August 2021 | pages=15 }}</ref> followed by the G8 Professional, these cards being demonstrated at the BBC Acorn User show in 1992, as was the Computer Concepts ColourCard.<ref name="acornuser199212_colourcards">{{ cite magazine | url=https://archive.org/details/AcornUser125-Dec92/page/n8/mode/1up | title=Colour Cards Arrive at Show | magazine=Acorn User | date=December 1992 | access-date=3 August 2021 | pages=7 }}</ref> One potentially significant difference between the different product ranges was the role of the VIDC, with the ColourCard employing a "video switch" that permitted the VIDC to generate an output signal independent of the card for traditional display modes, with the card only generating output for enhanced modes, whereas the State Machine cards were entirely responsible for output and thereby provided emulations of the traditional modes, this leading to a "letter-box" effect for some modes in early versions of the State Machine software and also causing compatibility issues with software, particularly games, that accessed VIDC registers directly to configure the display.<ref name="archimedesworld199310_vidc">{{ cite magazine | url=https://archive.org/details/acorn-archimedes-world-oct-1993/page/41/mode/1up | title=VIDC killed the video star | magazine=Archimedes World | date=October 1993 | access-date=26 August 2021 | pages=41–43 }}</ref> Subsequent developments from State Machine brought the G16 card, offering application-specific support for 15 and 16 bits per pixel modes.<ref name="acornuser199308_statemachine">{{ cite magazine | url=https://archive.org/details/AcornUser133-Aug93/page/n10/mode/1up | title=State Machine Sends Cards | magazine=Acorn User | date=August 1993 | access-date=4 August 2021 | pages=9 }}</ref>

Alongside bandwidth constraints, a fundamental limitation to the size of VIDC framebuffers was imposed by the memory controller, limiting the size of framebuffers transferred to the VIDC through [[Direct memory access|DMA]] to a specific 512&nbsp;KB physical memory region.<ref name="acorn_memc">{{ cite book | url=https://archive.org/details/memc_datasheet_sep86/page/n39/mode/1up | title=MEMC Datasheet | publisher=Acorn Computers Limited | date=30 September 1986 | volume=1 | access-date=11 September 2021 | isbn=1852500255 | pages=72 | quote=The DMA Address Generators can only address 512kBytes }}</ref> State Machine's ColourBurst card, announced together with its G16 card, employed memory mapping techniques to provide 1&nbsp;MB of video RAM instead of the 512&nbsp;KB of earlier cards and thus supporting larger screen modes.<ref name="acornuser199308_statemachine" /> The ColourBurst was, when reviewed in late 1993, the first 24-bit colour card available for the Archimedes, also supporting various upgrades including the "video switch" capability absent from earlier cards, PAL encoding, and other professional capabilities.<ref name="archimedesworld199310_colourburst">{{ cite magazine | url=https://archive.org/details/acorn-archimedes-world-oct-1993/page/44/mode/2up | title=Card Watch | magazine=Archimedes World | date=October 1993 | access-date=26 August 2021 | last1=Carlisle | first1=Chris | pages=44–46 }}</ref>

Coincidentally, ARM Limited announced the VIDC20—the successor to the VIDC10 in the Archimedes—at around the same time as the introduction of the Computer Concepts and State Machine product ranges in late 1992.<ref name="acornuser199212_vidc20">{{ cite magazine | url=https://archive.org/details/AcornUser125-Dec92/page/n8/mode/1up | title=VIDC20 Announced | magazine=Acorn User | date=December 1992 | access-date=3 August 2021 | pages=7 }}</ref> By late 1993, rumours about Acorn's next-generation system (eventually released as the Risc PC), particularly 24-bit colour support, led to suggestions of improved support for higher colour depths in RISC OS, accompanied by the observation in the context of State Machine's ColourBurst card that "it seems unlikely that another manufacturer will release such a powerful device before the launch of Acorn's new baby".<ref name="archimedesworld199310_colourburst" /> In late 1993, Computer Concepts announced the ColourCard Gold, developed in conjunction with Acorn to offer 15 bits per pixel support in the desktop environment. Meanwhile, State Machine announced the ClusterCard for 33&nbsp;MHz A5000 models, plugging into the memory controller socket and supporting upgrades to 8&nbsp;MB of RAM alongside graphics enhancements offering 1&nbsp;MB or 2&nbsp;MB of video RAM.<ref name="acornuser199401_graphics">{{ cite magazine | url=https://archive.org/details/AcornUser138-Jan94/page/n16/mode/1up | title=Graphics cards galore | magazine=Acorn User | date=January 1994 | access-date=4 August 2021 | pages=17 }}</ref> The ClusterCard, employing the G335 Cluster Module was reported to be the first graphics card for the Archimedes series not requiring the use of the VIDC.<ref name="acornuser199402_clustercard">{{ cite magazine | url=https://archive.org/details/AcornUser139-Feb94/page/n16/mode/1up | title=Cluster Card news | magazine=Acorn User | date=February 1994 | access-date=4 August 2021 | pages=17 }}</ref>

With IBM PC compatible systems leaving the Archimedes "well behind the competition in the display stakes", the ClusterCard was seen as attempting a solution similar to a [[VESA Local Bus|local bus]] architecture on the A5000, with the potential to "transform the A5000 into a serious graphics machine, with possibly as good a display potential as the next Acorn series equipped with VIDC20s".<ref name="acornuser199403_cards">{{ cite magazine | url=https://archive.org/details/AcornUser140-Mar94/page/n37/mode/2up | title=All on the cards | magazine=Acorn User | date=March 1994 | access-date=4 August 2021 | last1=Kreindler | first1=Jack | pages=38–40 }}</ref> The launch of the Risc PC in 1994 demonstrated Acorn's successor to the Archimedes, to which State Machine responded with a product called ColourView, "an all-new replacement for the original G8 and G16 State Machine graphics cards", offering 16 bits per pixel desktop-compatible screen modes, with a modular version also available for the ClusterCard without the 1&nbsp;MB framebuffer. The full version of the card was reportedly available for A300 series, A400 series, A5000 and A540 machines.<ref name="acornuser199406_colourview">{{ cite magazine | url=https://archive.org/details/AcornUser143-Jun94/page/n12/mode/1up | title=Next Generation of Graphics Card | magazine=Acorn User | date=June 1994 | access-date=4 August 2021 | pages=13 }}</ref>

Somewhat distinct from general graphics enhancements, various products were also introduced to support the broadcasting industry and other professional imaging applications. In late 1990, Millipede Electronic Graphics announced an imaging product called APEX (Archimedes P3 Expansion) featuring "four P3 (pixel pipeline processor) chips, together with an Arm3 processor running at 27&nbsp;MHz". With support for "broadcast quality graphics at 32 bits per pixel", hardware support for windows and sprites, emphasising real-time image combination and manipulation, the product was aimed at professional users and priced accordingly, with the version providing 4&nbsp;MB of RAM projected to cost £2750. Nevertheless, a licensing agreement had been reached with Acorn to "enable Risc OS graphics functions to be fully emulated".<ref name="acornuser199012_apex">{{ cite magazine | url=https://archive.org/details/AcornUser101-Dec90/page/n10/mode/1up | title=The New APEX Podule | magazine=Acorn User | date=December 1990 | access-date=4 August 2021 | pages=9 }}</ref> Following up from this earlier product, Millipede offered an "all new Apex Imager" video card in early 1994 featuring the four custom chips, ARM3, FPA, and 16&nbsp;MB of video RAM on a double-width podule costing £3975, this being virtually unchanged from the pricing of the original product from 1990.<ref name="acornuser199401_apex">{{ cite magazine | url=https://archive.org/details/AcornUser138-Jan94/page/n16/mode/1up | title=Video cards deluxe | magazine=Acorn User | date=January 1994 | access-date=4 August 2021 | pages=17 }}</ref> This product appears to make extensive use of FPGA devices and offers numerous video input and output facilities.<ref name="cch_apex_imager">{{ cite web | url=http://www.computinghistory.org.uk/det/24771/Apex-Imager-P3-Issue-4/ | title=Apex Imager P3 Issue 4 | website=Centre for Computing History | access-date=4 August 2021 }}</ref> Apex hardware was used by the [[Square Enix Europe#Eidos Interactive|Eidos]] video capture and compression solution, Thumper, which ran on a Risc PC and was able to process "MPEG 1 resolution video at full PAL frame rate in real time", being regarded in early 1995 as "the best digitiser for our needs on any platform" by Eidos' managing director.<ref name="acornuser199501_apex">{{ cite magazine | url=https://archive.org/details/AcornUser151-Jan95/page/n42/mode/1up | title=Making movies | magazine=Acorn User | date=January 1995 | access-date=29 October 2021 | last1=Kriendler | first1=Jack | last2=Streater | first2=Stephen B. | pages=43–45 }}</ref> Previous Eidos capture solutions used A540 machines with 8&nbsp;MB of RAM.<ref name="acornusr199308_eidos" />

=== Sound and audio ===

The Archimedes was capable of producing eight-channel, 8-bit, stereo sound, with the video controller chip being responsible for sound generation, it having direct memory access capabilities to independently stream audio data to the output circuitry.<ref name="vidc_datasheet" />{{rp|pages=2,21,32}} Some users sought to bypass the audio filtering circuitry to improve sound from the external audio connector.<ref name="acornuser199112_audio">{{ cite magazine | url=https://archive.org/details/AcornUser113-Dec91/page/n26/mode/1up | title=£15 Star Letter | magazine=Acorn User | date=December 1991 | access-date=11 August 2021 | last1=Bristow | first1=C. M. | pages=25 }}</ref>

=== Floating-point arithmetic ===

The Archimedes did not provide hardware support for [[floating-point arithmetic]] as standard, but the system was designed so that one might be added, with a floating-point co-processor instruction set architecture having been defined by Acorn for programs to use. As part of the system architecture, a software module provides an emulation of such a co-processor, handling floating-point instructions unsupported in hardware using software written using conventional ARM instructions. The co-processor was described as a "cut-down" ARM with only eight registers available instead of sixteen, offering instructions to transfer values to and from memory (supporting single, double, extended double and packed [[binary-coded decimal]] representations<ref name="acornuser198905_fp">{{ cite magazine | url=https://archive.org/details/AcornUser082-May89/page/n86/mode/1up | title=Arithmetic on the Dot | magazine=Acorn User | date=May 1989 | access-date=7 May 2021 | last1=Chappell | first1=Tim | pages=85–86 }}</ref>), to transfer values between the main CPU and co-processor, to transfer status information from the co-processor, to perform unary and binary operations on values, and to perform comparisons.<ref name="acornuser198904_fp">{{ cite magazine | url=https://archive.org/details/AcornUser081-Apr89/page/n67/mode/2up | title=Get to the Point | magazine=Acorn User | date=April 1989 | access-date=3 May 2021 | last1=Chappell | first1=Tim | pages=66–69 }}</ref>

In the first generation of Archimedes 300 and 400 series machines, only the 400 series had the appropriate expansion capability to add a floating-point unit (FPU) or co-processor, although the emulator was supported on all models.<ref name="acorn_app118_issue3">{{ cite book | url=http://chrisacorns.computinghistory.org.uk/docs/Acorn/Brochures/Acorn_APP118_ArchimedesNov87.pdf | title=High Performance Computer Systems | publisher=Acorn Computers Limited | date=November 1987 | issue=3 | access-date=3 May 2021 | pages=11 | quote=All ARCHIMEDES systems have a floating-point emulator as standard. On the 400 Series, complex mathematical calculations can be further enhanced by the addition of a floating-point unit (FPU). }}</ref> The expansion capability was retained in the 400/1 series.<ref name="acorn_app230">{{ cite book | url=http://chrisacorns.computinghistory.org.uk/docs/Acorn/Brochures/Acorn_APP230_Archimedes4001.pdf | title=High Performance Computer Systems Archimedes 400/1 Series | publisher=Acorn Computers Limited | date=September 1989 | issue=1 | access-date=3 May 2021 | pages=3 }}</ref> The FPU expansion card was delivered for the R140 workstation and 400 series in 1989, priced at £599 plus VAT, and was based on the WE32206,<ref name="APP221">{{ cite book | url=http://chrisacorns.computinghistory.org.uk/docs/Acorn/Brochures/Acorn_APP221_R140ComputerSystemsJun89.pdf | title=R140 Computer Systems | publisher=Acorn Computers Limited | edition=3 | date=June 1989 | access-date=6 September 2020 }}</ref> with a "protocol converter chip" being used to translate between the ARM and the WE32206.<ref name="newcompexpress19880203">{{ cite magazine | url=https://archive.org/details/NH2021_New_Computer_Express_Issue065.pdf/page/n17/mode/2up | title=ARM3 versus FPU | magazine=New Computer Express | date=3 February 1988 | access-date=3 May 2021 | last1=Carrot | first1=Bertram | pages=18 }}</ref> The WE32206 card was also offered for Acorn's Springboard expansion card for IBM PC compatibles.<ref name="pcw198801">{{ cite magazine | url=https://archive.org/details/bitsavers_acornAcornboard_256399/mode/2up | title=Acorn Springboard | magazine=Personal Computer World | date=January 1988 | access-date=3 May 2021 | last1=Pountain | first1=Dick | pages=118–120 }}</ref> Although Acorn had expected that interfacing the ARM to an existing FPU chip would be "a much quicker route" to delivering a hardware-based floating-point solution than developing a new co-processor, the complexity involved in developing the custom gate array responsible for interfacing to the WE32206 was apparently greater than anticipated, taking two years to deliver.<ref name="abcomputing199003_arm">{{ cite magazine | title=Programming The ARM: The Floating Point Co-processor | magazine=A&B Computing | last1=Fellows | first1=Paul | date=March 1990 | pages=43–44 }}</ref>

Reviews of the FPU were generally unenthusiastic, noting that Acorn's claims of an eight-fold speed-up were unlikely to be achieved in "a practical program", nevertheless reporting that programs performing repeated floating-point operations yielded speed-ups ranging from around four to sixteen times that of a base ARM2-based system.<ref name="riscuser198912_fpu">{{ cite magazine | url=https://archive.org/details/risc-user-vol-3-iss-02-dec-89/page/49/mode/1up | title=Acorn's Floating Point Unit | magazine=RISC User | date=December 1989 | access-date=18 October 2022 | last1=Spencer | first1=David | pages=49 }}</ref> Somewhat more applied testing demonstrated speed-ups for benchmark programs of up to eight times, aligning with Acorn's claims, but contrasted these gains with the broader performance increases attainable from an ARM3 upgrade, these offering a more general four-fold speed improvement. Largely focusing on BASIC programming, one reviewer concluded that the FPU was "all but obsolete" with the availability of the ARM3 upgrade.<ref name="archive199011_fpu">{{ cite magazine | url=https://archive.org/details/Archive_1990-11_OCR/page/n44/mode/1up | title=Hardware Column | magazine=Archive | date=November 1990 | access-date=18 October 2022 | last1=Cowan | first1=Brian | pages=43–44 }}</ref> Another conceded that some but not all C programs would benefit from the FPU since "a good programmer will avoid using floating point instructions if at all possible", suggesting that Acorn's R140 workstation would benefit more from the upgrade.<ref name="riscuser198912_fpu"/> However, BASIC programs compiled using the Archimedes BASIC Compiler achieved over nine-fold speed-ups for certain benchmarks, unlike those running on the standard BASIC interpreter whose floating-point routines avoided using FPU instructions, thus delivering no real performance improvements with the FPU fitted.<ref name="abcomputing199003_arm"/>

The Archimedes models based on the ARM3 processor supported a completely new "arithmetic co-processor" or "floating-point accelerator" known as the FPA. Released in 1993 for the R260 workstation and the A540 and A5000 machines, priced at £99 plus VAT, the FPA device—known specifically as the FPA10—was fitted in a dedicated socket on the processor card for the R260 and A540, or in a motherboard socket in the A5000. It offered a peak throughput of 5&nbsp;[[MFLOPS]] at 26&nbsp;MHz.<ref name="acorn_fpa10">{{ cite press release | url=http://chrisacorns.computinghistory.org.uk/docs/Acorn/PR/FPA_release.txt | title=Acorn Releases Floating Point Accelerator | publisher=Acorn Computers Limited | date=5 July 1993 | access-date=7 April 2021 }}</ref> The models officially supporting the FPA had been introduced some time prior to availability of the device, and various ARM3 upgrade cards for earlier models had also been made available with an FPA socket in anticipation of eventual availability.<ref name="acornuser199211_fpa">{{ cite magazine | url=https://archive.org/details/AcornUser124-Nov92/page/n15/mode/1up | title=Upgrade for FPA | magazine=Acorn User | date=November 1992 | access-date=26 June 2021 | pages=12 }}</ref> Fabrication of the device was performed by GEC Plessey Semiconductors and was reported to be in "an advanced stage of production" in early 1993.<ref name="acornuser199306_fpa">{{ cite magazine | url=https://archive.org/details/AcornUser131-Jun93/page/n8/mode/1up | title=FPA Floats this Way | magazine=Acorn User | date=June 1993 | access-date=26 June 2021 | pages=7 }}</ref> Availability remained unclear, with ARM releasing technical details indicating that the chip, at 134,000 [[transistors]] was reportedly "Arm's most complex IC to date" and comparing its performance at "around 4&nbsp;MFLOPS" to the MIPS R3010 floating-point co-processor, whilst claiming a substantial power consumption advantage.<ref name="acornuser199308_fpa">{{ cite magazine | url=https://archive.org/details/AcornUser133-Aug93/page/n8/mode/1up | title=Acorn Skips Generation to 700 | magazine=Acorn User | date=August 1993 | access-date=26 June 2021 | pages=7 }}</ref> Further details were given upon the eventual release of the FPA10, stating a 26&nbsp;MHz operating frequency and a power consumption of 250&nbsp;mW. Reception from major software producers such as Computer Concepts and Colton Software was cautious, with the former's products not making any use of floating-point instructions and thus not standing to benefit, and with the latter's using such instructions but indicating skepticism about any significant benefits in performance.<ref name="acornuser199309_fpa">{{ cite magazine | url=https://archive.org/details/AcornUser134-Sep93/page/n8/mode/1up | title=FPA10 Brings Faster Maths | magazine=Acorn User | date=September 1993 | access-date=26 June 2021 | pages=7 }}</ref>

Observations from testing the FPA10 confirmed that applications such as Resultz and PipeDream 4—both Colton Software products—and other spreadsheets, whilst ostensibly standing to benefit as number processing applications, exhibited "no noticeable speed improvements", this being attributed to these applications' avoidance of unnecessary calculation and the more significant overhead of servicing a graphical user interface. Other programs such as Draw and ArtWorks—a Computer Concepts product—used their own arithmetic routines instead of the floating-point emulator (FPE) and, as anticipated, were therefore unable to take advantage of the accelerated floating-point instructions. However, various free of charge or low-cost programs [[porting|ported]] from other systems, such as [[POV-Ray]], plus selected native applications such as Clares' Illusionist and Oak Solutions' WorraCAD, did exhibit substantial performance gains from the FPA with speed-ups of between five and ten times. Programs compiled by Intelligent Interfaces' Fortran compiler were reported as running "some routines up to 20 times faster with the FPA10".<ref name="acornuser199310_fpa"/> Although the FPA10 only implemented arithmetic operations, delegating trigonometric operations to the FPE, it was able to operate concurrently with the main CPU and maintained its own instruction pipeline, allowing the CPU to proceed with other instructions until a floating-point instruction result was required.<ref name="riscuser199310_fpa"/> Speculative execution was also employed to improve performance.<ref name="harrod93">{{ Cite conference | url=https://ieeexplore.ieee.org/document/590407 | book-title=Proceedings of IEEE Custom Integrated Circuits Conference - CICC '93 | last1=Harrod | first1=P. L. | last2=Baum | first2=A. J. | last3=Biggs | first3=J. P. | last4=Howard | first4=D. W. | last5=Merritt | first5=A. J. | last6=Oldham | first6=H. E. | last7=Seal | first7=D. J. | last8=Watters | first8=H. L. | title=FPA10-A 4 MFLOP floating point coprocessor for ARM | doi=10.1109/CICC.1993.590407 | isbn=0-7803-0826-3 | date=1993 | access-date=13 January 2025 | pages=4.3.1–4.3.4 }}</ref><ref name="gps_fpa10">{{ cite book | url=http://chrisacorns.computinghistory.org.uk/docs/GECPlessey/GECPlessey_FPA10DataSheet.pdf | title=ARM FPA10 Data Sheet | publisher=GEC Plessey Semiconductors | date=11 June 1993 | issue=1 | access-date=13 January 2025 }}</ref>

Observed BASIC program performance remained in line with experiences from the earlier FPU solution. The BASIC VI (or Basic64) interpreter bundled with RISC OS which was "much slower than Basic V normally", with the former using the FPE and the latter providing its own floating-point arithmetic routines, ended up "slightly faster" than BASIC V due to observed speed-ups of around four to around eleven times, with non-trigonometric operations benefiting the most in one analysis.<ref name="acornuser199310_fpa"/> Another analysis employing benchmarks of individual arithmetic and trigonometric operations indicated a more uniform distribution of performance improvements for BASIC VI programs, also noting that BASIC VI delivered more precision than BASIC V in its floating-point representation.<ref name="riscuser199310_fpa">{{ cite magazine | url=https://archive.org/details/risc-user-vol-6-iss-10-1993-october/page/n22/mode/2up | title=The New Acorn Floating Point Accelerator | magazine=RISC User | date=October 1993 | access-date=9 November 2023 | last1=Spencer | first1=David | pages=22–23 }}</ref> The product was perceived as "good value" but having restricted usefulness with the general lack of support in many applications, these employing their own routines and techniques to attempt to provide performant arithmetic on the base hardware platform, and a lack of incentive amongst software producers to offer support without a large enough market of users having the FPA fitted.<ref name="acornuser199310_fpa">{{ cite magazine | url=https://archive.org/details/AcornUser135-Oct93/page/n64/mode/1up | title=Float On | magazine=Acorn User | date=October 1993 | access-date=26 June 2021 | last1=Burley | first1=Ian | pages=63 }}</ref>

With the FPA10 having finally become available but only rated to run at 26&nbsp;MHz, and with ARM3 upgrades being delivered at frequencies as high as 35&nbsp;MHz,<ref name="acornuser199306_ifel" /> a higher-rated part, the FPA11, supporting 33&nbsp;MHz operation was developed<ref name="acornuser199509_range">{{ cite magazine | url=https://archive.org/details/AcornUser159-Sep95/page/n8/mode/1up | title=Acorn broadens its range | magazine=Acorn User | date=September 1995 | access-date=11 October 2021 | pages=9 }}</ref> and apparently delivered in products such as a processor card upgrade for the A540.<ref name="acorn_fpa11_a540">{{ cite web | url=http://www.computinghistory.org.uk/det/36127/Acorn%20A500%20ARM3%20CPU%20with%20FPA11/ | title=Acorn A500 ARM3 CPU with FPA11 | website=Chris's Acorns | access-date=11 October 2021 }}</ref> ARM3 upgrades were also produced with 33&nbsp;MHz ARM3 processors, but unlike their 25&nbsp;MHz counterparts which were available with FPA10 co-processors already fitted, these faster cards were not supplied with FPA11 co-processors, perhaps due to availability issues with the faster part.<ref name="acornuser199705_simtec" />

=== ARM3 upgrades ===

In early 1990, Aleph One introduced an upgrade board for Archimedes A300 and A400 series models featuring the ARM3 processor which had been designed by Acorn but was sold independently by VLSI Technology.<ref name="electronicnews19890417_arm3">{{ cite magazine | url=https://archive.org/details/sim_electronic-news_1989-04-17_35_1754/page/n24/mode/1up | title=VLSI Debuts SRAM Designed With Hitachi | magazine=Electronic News | date=17 April 1989 | access-date=28 December 2021 | pages=25 }}</ref> Although the ARM2 employed by current models could reportedly be run at 20&nbsp;MHz, it was only ever run at 8&nbsp;MHz due to external limitations, these being the speed of the data bus and of the "relatively slow", but correspondingly relatively inexpensive, RAM devices in use. The ARM3 incorporated a 4&nbsp;KB on-chip combined instruction and data cache, loosening such external constraints and thus permitting the processor to be run productively at the elevated 20&nbsp;MHz frequency. With a processor running at this higher speed, the overall performance of a computer with the ARM3 upgrade was reported as double that of the machine without the upgrade ("on average, execution times were halved"), with programs performing input/output benefiting rather less ("a worst case of 30 percent improvement"). Original A300 and A400 series models, as opposed to the A400/1 series, required an upgrade to MEMC1a. One hundred percent compatibility with the ARM2 was claimed, and a facility was provided to disable the on-chip cache and to slow the clock to 8&nbsp;MHz in order to handle software that ran too fast with the ARM3 running at full speed, but as originally provided, the ARM3 was not compatible with the existing hardware floating point co-processor solution due to the introduction of a different co-processor interface in the device, this interface eventually being used by the FPA device. The upgrade was introduced at a price of £684.24, with the MEMC1a costing £57.50 for those users who needed it.<ref name="acornuser199002_arm3">{{ cite magazine | url=https://archive.org/details/AcornUser091-Feb90/page/n126/mode/1up | title=Fast Work | magazine=Acorn User | date=February 1990 | access-date=14 July 2021 | last1=Howarth | first1=Roger | pages=125 }}</ref>

By the end of 1991, an ARM3 upgrade had been offered for the A3000 by Aleph One in association with Atomwide and by Watford Electronics. Since the ARM2 was soldered directly to the motherboard in the A3000 using surface mounting techniques, the upgrade had to be performed by a fitting service, and prices included courier collection, fitting, testing and return within five working days. With the A5000 having been launched with a 25&nbsp;MHz ARM3 fitted, these A3000 upgrade boards carried a processor running at this higher frequency relative to earlier upgrades. Originally, the Aleph One product had been priced at £468.83, but the announcement of a board by Watford Electronics led to a reduced price of £392.45. The Watford product had an introductory price of £274.95.<ref name="acornuser199112_turbo">{{ cite magazine | url=https://archive.org/details/AcornUser113-Dec91/page/n146/mode/1up | title=Turbo A3000 | magazine=Acorn User | date=December 1991 | access-date=14 July 2021 | last1=James | first1=Paul | pages=145–146 }}</ref>

Other vendors produced ARM3 upgrades. In late 1992, Simtec Electronics announced a board with an additional socket for the FPA device, thus allowing older machines to join the A540 and A5000 in potentially taking advantage of it. By this time, prices for ARM3 upgrades had been reduced to the point that this Simtec upgrade cost only £175 plus VAT.<ref name="acornuser199211_simtec">{{ cite magazine | url=https://archive.org/details/AcornUser124-Nov92/page/n15/mode/1up | title=Upgrade for FPA | magazine=Acorn User | date=November 1992 | access-date=14 July 2021 | pages=12 }}</ref> Competitors including IFEL and CJE Micros followed Simtec's lead and announced similar combined ARM3/FPA upgrades. In contrast, Aleph One stated that the FPA would "not be available for a long time yet", indicating the pursuit of "a better solution based on the newer Arm600 chip plus an FPA". Other vendors had apparently ruled out similar ARM600-based products on the basis of cost.<ref name="acornuser199212_arm3">{{ cite magazine | url=https://archive.org/details/AcornUser125-Dec92/page/n8/mode/1up | title=ARM Race | magazine=Acorn User | date=December 1992 | access-date=14 July 2021 | pages=7 }}</ref> In 1993, IFEL later announced a 35&nbsp;MHz ARM3 upgrade based on a limited quantity—approximately 1500—of available suitably rated parts, these having a ceramic package whose volume ruled out its use in machines with limited internal space, making the upgrade suitable for A300, A400 or R140 machines. A combined ARM3/FPA upgrade with the faster ARM3 was under consideration, although the lack of suitably rated FPA chips meant that a switch would be provided to manually change the clock frequency between 25&nbsp;MHz and 35&nbsp;MHz. A target price of £199 including VAT was estimated.<ref name="acornuser199306_ifel">{{ cite magazine | url=https://archive.org/details/AcornUser131-Jun93/page/n11/mode/1up | title=Ifel Ultra-Fast ARM3 Upgrade | magazine=Acorn User | date=June 1993 | access-date=14 July 2021 | pages=10 }}</ref>

Prior to the availability of the FPA, Simtec reduced the price of its combined ARM3/FPA board to £165 plus VAT. The company also released a "turbo RAM" upgrade for ARM250-based machines to provide similar performance benefits to an ARM3 upgrade, replacing the RAM with a faster type that then permitted the processor to be run at a higher frequency, thus pursuing the alternative approach to enhancing system performance (increasing both the processor and memory speed) to that pursued by ARM3 upgrades (introducing a faster processor with a cache). With the upgrade, performance of these machines was reported as increasing from 7 MIPS to 10 MIPS, this compared to almost 13 MIPS for a 25&nbsp;MHz ARM3.<ref name="acornuser199305_turbo">{{ cite magazine | url=https://archive.org/details/AcornUser130-May93/page/n16/mode/1up | title=Speeding up the ARM | magazine=Acorn User | date=May 1993 | access-date=15 July 2021 | pages=13 }}</ref> By employing a 16&nbsp;MHz clock signal, as envisaged by Acorn in the design of the A3010, in conjunction with dynamic RAM devices with a 70&nbsp;ns access time, the upgrade provided a total of 4&nbsp;MB of RAM and a 40 percent performance improvement. Unlike standard RAM upgrades, the turbo upgrade needed to be fitted at a suitable facility, and the board was priced slightly higher than a standard RAM upgrade at £129 plus VAT. A "super turbo" version of the board with 20&nbsp;MHz crystal and 45&nbsp;ns dynamic RAM devices was reviewed and apparently available subject to component availability, reportedly achieving 12.25 MIPS.<ref name="acornuser199307_turbo">{{ cite magazine | url=https://archive.org/details/AcornUser132-Jul93/page/n68/mode/1up | title=Ahead of the pack | magazine=Acorn User | date=July 1993 | access-date=15 July 2021 | last1=Lawrence | first1=Dave | pages=67–68 }}</ref>

Aleph One, having founded the ARM3 upgrade industry, found that increased competition from "six or eight companies making Arm3 upgrades" drove down prices to the point that "margins fell, and the bottom fell out of the Arm3 market". However, revenues from ARM3 upgrades allowed Aleph One to pursue the development of IBM PC-compatible podule expansions and eventually the PC processor card for the Risc PC, these having "a higher intellectual content than Arm3 upgrades" and being more difficult for potential competitors to make. Plans were indicated to develop a PowerPC processor card for the Risc PC.<ref name="acornuser199410_lvs">{{ cite magazine | url=https://archive.org/details/AcornUser147-Oct94/page/n97/mode/1up | title=The Moxon Interview - Laurie van Someren | magazine=Acorn User | date=October 1994 | access-date=14 July 2021 | last1=Moxon | first1=Mark | pages=98 }}</ref> Neither the PowerPC upgrade for the Risc PC nor the earlier ARM600-based upgrade for the Archimedes series appeared, with Acorn itself abandoning plans to combine newer ARM600 or ARM700 parts with FPA devices to provide improved floating point performance.<ref name="acorn_floating_point_support_riscpc">{{ cite press release | url=http://chrisacorns.computinghistory.org.uk/docs/Acorn/PR/Floating_point_support_for_the_Risc_PC.txt | title=Floating Point Support for the Risc PC | publisher=Acorn Computers Limited | access-date=14 July 2021 }}</ref>

ARM3 upgrades were produced for several years, but with the ARM3 part being "officially discontinued" by its manufacturer VLSI in 1996, upgrade vendors such as IFEL were predicting scarcity and unable to guarantee further supplies of such products. Demand for such upgrades, even in 1996, was reported as "steady" with schools still upgrading "batches of old A300 and A400 machines".<ref name="acornuser199610_ifel">{{ cite magazine | url=https://archive.org/details/AcornUser173-Oct96/page/n12/mode/1up | title=IFEL update | magazine=Acorn User | date=October 1996 | access-date=29 August 2021 | pages=13 }}</ref> Later still, in 1997, Simtec announced a "special batch" of ARM3 upgrades for A300 and A400 series machines and the A3000, featuring a socket for the 25&nbsp;MHz FPA10 or 33&nbsp;MHz FPA11, with the former being supplied already fitted for a total product cost of £199 plus VAT.<ref name="acornuser199705_simtec">{{ cite magazine | url=https://archive.org/details/AcornUser181-May97/page/n5/mode/1up | title=33MHz ARM3 FPA upgrades | magazine=Acorn User | date=May 1997 | access-date=11 October 2021 | pages=6 }}</ref>

=== IBM PC-compatible podules ===

Acorn initially planned to produce an IBM PC-compatible system on a podule (peripheral module), complete with 80186 processor (running at 10&nbsp;MHz<ref name="acorn_app118_issue1" />{{rp|pages=12|quote=A 10 MHz 80186 co-processor unit running MS-DOS. }}) and disk drive support.<ref name="acornuser198710_pc" /> Subsequent pricing and competitiveness considerations led to the product being shelved.<ref name="acornuser198802_pc" /> However, in late 1991, hardware supplier Aleph One announced a PC podule based on a 20&nbsp;MHz Intel 80386SX processor with VGA display capability.<ref name="acornuser199110_aleph1pc">{{ cite magazine | url=https://archive.org/details/AcornUser111-Oct91/page/n10/mode/1up | title=PC Compatibility Podule for the Arc Now Ready | magazine=Acorn User | date=October 1991 | access-date=5 June 2021 | pages=9 }}</ref> Launched in early 1992, the podule fitted with 1&nbsp;MB of RAM cost £595, whereas a 4&nbsp;MB version cost £725.<ref name="acornuser199203_aleph1pc">{{ cite magazine | url=https://archive.org/details/AcornUser116-Mar92/page/n8/mode/1up | title=PC on a Card for the Arc | magazine=Acorn User | date=March 1992 | access-date=6 June 2021 | pages=7 }}</ref> Known as the 386PC, the expansion was "in effect, a PC within your Archimedes" whose RAM could be upgraded from the minimum of 1&nbsp;MB, the price of this configuration having fallen to £495 at the time of its review, to the maximum of 4&nbsp;MB, with this configuration also being offered at a reduced price of £625. A socket on the board permitted the [[X87#80387|80387 maths co-processor]] to be fitted for hardware floating point arithmetic support, this costing an extra £120. Integration of the PC system involved the Archimedes providing display, keyboard and disk support. In the initial version, the supplied 386PC application would put the Archimedes into dedicated display mode and thus take over the display, but subsequent versions promised operation of the PC in a window, much like the updated PC Emulator from the era. Screen memory requirements were around 256&nbsp;KB for MDA and CGA, with EGA and VGA requiring another 256&nbsp;KB. Separate serial and parallel ports were fitted on the expansion board due to limitations with the ports on existing Archimedes machines, but integration with those ports was also planned for subsequent versions of the product.<ref name="acornuser199205_aleph1pc">{{ cite magazine | url=https://archive.org/details/AcornUser118-May92/page/n107/mode/2up | title=The PC Inside Your Arc | magazine=Acorn User | date=May 1992 | access-date=6 June 2021 | last1=Brown | first1=Malcolm | pages=106–108 }}</ref>

Watford Electronics, in association with "prolific ex-Computer Concepts hardware expert" Chris Honey, announced a PC podule in early 1992, this effectively delivering "a stand-alone PC" within the host computer and potentially allowing two independent users with their own keyboards and monitors, although the PC system would be accessible via a desktop window and have access to RISC OS hard drive partitions.<ref name="acornuser199204_watford">{{ cite magazine | url=https://archive.org/details/AcornUser117-Apr92/page/n11/mode/1up | title=Watford to Launch a New PC Podule | magazine=Acorn User | date=April 1992 | access-date=30 June 2022 | pages=10 }}</ref> This product was apparently never released, however, and its designers subsequently formed graphics expansion producer State Machine.<ref name="acornuser199208_statemachine"/> In late 1992, Aleph One reduced the price of the 386-based card by £100, also upgrading the processor to a 25&nbsp;MHz part, and introduced a card featuring a 25&nbsp;MHz [[Cyrix Cx486SLC|Cyrix 486SLC]] processor, with the new card retaining the maths co-processor option of the earlier product. The stated performance of this new card was approximately twice that of the 386-based card but only "40 percent of the performance of a standard 33&nbsp;MHz 486DX PC clone". However, upgraded Windows drivers reportedly allowed even the 386-based card to exceed the graphical performance of such a 486-based clone, effectively employing the host Archimedes as a kind of "Windows accelerator".<ref name="acornuser199211_aleph1pc486">{{ cite magazine | url=https://archive.org/details/AcornUser124-Nov92/page/n14/mode/1up | title=486 PC Card for Price of a 386 | magazine=Acorn User | date=November 1992 | access-date=15 June 2021 | pages=11 }}</ref> A subsequent review moderated such claims somewhat, indicating a Windows performance "not noticeably better than an average un-accelerated 386SX PC clone", although acceleration support was expected to improve, with device drivers for various direct drive laser printers also expected. The product was priced at £495 for the 1&nbsp;MB version and £595 for the 4&nbsp;MB version, with a future revision of the product anticipated that would support up to 16&nbsp;MB of RAM.<ref name="acornuser199302_aleph1pc486">{{ cite magazine | url=https://archive.org/details/AcornUser127-Feb93/page/n120/mode/1up | title=Easy PC | magazine=Acorn User | date=February 1993 | access-date=15 June 2021 | last1=Burley | first1=Ian | pages=119 }}</ref>

In 1993, Aleph One collaborated with Acorn to produce Acorn-branded versions of the PC cards for use with the A3020 and A4000 which used a distinct "mini-podule expansion system". The 25&nbsp;MHz 386SX and 486SLC cards were offered in this profile to provide DOS and Windows compatibility,<ref name="acornuser199303_aleph1pc">{{ cite magazine | url=https://archive.org/details/AcornUser128-Mar93/page/n11/mode/1up | title=Acorns and PCs Meet | magazine=Acorn User | date=March 1993 | access-date=19 June 2021 | pages=10 }}</ref> branded as the PC386 and PC486, priced at £275 and £499 respectively. In late 1993, the supplied software was upgraded and discounts to the products announced, bringing the respective prices down to £225 and £425. Acorn also offered bundles of the A4000 with a hard drive and each of the cards.<ref name="acornuser199312_acorn_pc">{{ cite magazine | url=https://archive.org/details/AcornUser137-Dec93/page/n8/mode/1up | title=Acorn card price cut offers cheaper PC compatibility | magazine=Acorn User | date=December 1993 | access-date=19 June 2021 | pages=7 }}</ref> Coincidentally at this time, with speculation building about future Acorn computer products, Acorn's product marketing manager had been reported as suggesting that such products "would have an empty Intel socket for customers to add PC Dos and Windows compatibility". Such remarks were clarified by Acorn's technical director, indicating that an Intel "second processor" was merely an option in an architecture supporting multiple processors.<ref name="acornuser199312_intel">{{ cite magazine | url=https://archive.org/details/AcornUser137-Dec93/page/n8/mode/1up | title=Acorn Machines to Have Intel Inside? | magazine=Acorn User | date=December 1993 | access-date=19 June 2021 | pages=7 }}</ref> Ultimately, Acorn would release the [[Risc PC]] with dual processor capabilities and support for using a "low cost (£99 upwards) plug-in 486 PC processor or other CPUs" alongside an ARM processor.<ref name="acornuser199405_riscpc">{{ cite magazine | url=https://archive.org/details/AcornUser142-May94/page/n10/mode/1up | title=Risc PC, the Next Generation | magazine=Acorn User | date=May 1994 | access-date=19 June 2021 | pages=11 }}</ref>

Redesigned PC cards were released in 1994, introducing the option of a faster 50&nbsp;MHz [[Cyrix Cx486SLC|486SLC2]] processor for a reported doubling of the performance over the fastest existing cards. Up to 16&nbsp;MB of SIMM-profile RAM could be fitted, and a local hard drive controller was added. The supplied software was also upgraded to support Windows in a resolution of {{nowrap|800 x 600}} at up to 16 colours, and optional network driver support was available to use the card as a [[Novell NetWare]] client and for [[Windows for Workgroups 3.11]]. Pricing remained similar to earlier models.<ref name="acornuser199405_aleph1pc">{{ cite magazine | url=https://archive.org/details/AcornUser142-May94/page/n18/mode/1up | title=Mk II PC Podules from Aleph One | magazine=Acorn User | date=May 1994 | access-date=22 June 2021 | pages=19 }}</ref> Reported performance was better than the previous generation of cards but "still slow compared to all but the most basic of modern PCs, but certainly usable". The Windows User benchmarks rated the performance as similar to a fast 386SX-based system or a "standard" 386DX-based system, with the faster processor yielding a more favourable rating, but with the hard drive and graphics tests bringing the overall rating down. Use of a hard drive fitted directly to the card, using its own dedicated [[Integrated Drive Electronics|IDE]] interface, was reported as providing up to ten times the level of hard drive performance relative to using the system's own drive, but use of the [[SmartDrive]] caching software made any resulting performance difference marginal.<ref name="acornuser199408_aleph1pc">{{ cite magazine | url=https://archive.org/details/AcornUser145-Aug94/page/n78/mode/1up | title=Rock and roll Hardware | magazine=Acorn User | date=August 1994 | access-date=30 June 2021 | last1=Burley | first1=Ian | pages=79 }}</ref>

=== Parallel and data processing ===

A range of podules providing access to parallel processing capabilities using [[Inmos]] [[Transputer]] processors were announced by Gnome Computing in late 1989. Aside from a "Link Adaptor" podule for interfacing to external Transputer hardware, the "TRAM Motherboard" podule combined the Link Adaptor's interfacing logic with the hosting of up to four "TRAMs" (Transputer plus RAM modules), providing a complete development system based on the Archimedes. Also offered was a "Transputer Baseboard" podule featuring a T425 or T800 with up to 8&nbsp;MB of RAM.<ref name="archive198910_gnome">{{ cite magazine | url=https://archive.org/details/Archive_1989-10_OCR/page/n4/mode/2up | title=Products Available | magazine=Archive | date=October 1989 | access-date=5 August 2021 | pages=3–4 }}</ref> A single podule with four TRAMs, each employing a T800 processor, was stated as giving 40&nbsp;MIPS of performance, with a hypothetical 160&nbsp;MIPS available on an Archimedes with four podule slots.<ref name="acornuser198910_gnome">{{ cite magazine | url=https://archive.org/details/AcornUser087-Oct89/page/n10/mode/1up | title=Parallel Archimedes | magazine=Acorn User | date=October 1989 | access-date=5 August 2021 | pages=9 }}</ref>

[[Digital signal processing]] capabilities were provided by the Burden Neuroscience 56001 DSP Card, originally developed by the [[Burden Neurological Institute]] as in-house hardware for use in conjunction with Archimedes systems but marketed by The Serial Port. This card was fitted as a single-width podule but, unusually, needed manual configuration instead of identifying itself to the host computer. The podule itself offered a 32&nbsp;MHz [[Motorola 56001]] digital signal processor together with 192&nbsp;KB of RAM, two 16-bit analogue-to-digital converters, two 16-bit digital-to-analogue converters, and serial communications capabilities. A 25-pin connector provided the means to interface the board to other hardware. An assembler was provided, although this reportedly required Acorn's Desktop Development Environment to function, and software was also provided to interact with the board, view memory and register contents, and to visualise memory ranges in real time. Described as appropriate for "high speed analogue data acquisition or output" supporting real time signal processing, the product was considered "a useful 56001 development test bed", requiring a certain level of expertise, but was also considered good value at a price of £449 plus VAT.<ref name="acornuser199412_56001">{{ cite magazine | url=https://archive.org/details/AcornUser149-Dec94/page/n43/mode/2up | title=A card with 56001 uses? | magazine=Acorn User | date=December 1994 | access-date=1 December 2021 | last1=Craig-Wood | first1=Nick | pages=44–45 }}</ref>

=== CD-ROM and related storage ===

[[CD-ROM]] technology was introduced to the Archimedes range in 1990 with the launch of Next Technology's CD-ROM solution for the A3000 and earlier Archimedes models. Combining an [[SCSI]] interface and CD-ROM drive and supplied with a sample disc for a total price of £995, the solution provided a filing system so that standard CD-ROM media could be browsed and read like any other kind of disc. An application was also provided to play audio tracks on [[Compact Disc Digital Audio|CD Audio]] and mixed-format discs through the drive's headphone socket. The drive itself used a caddy to hold the discs inserted into the drive. One limitation experienced on RISC OS was with the content on various CD-ROM titles, this often being designed for MS-DOS and featuring DOS-only software to offer search and database-related functionality. Next Technology aimed to remedy this situation by offering a service to let users create their own CD-ROMs at around £300 per disc, leading to the initial conclusion that schools and institutional users would benefit from the format much more than home users.<ref name="acornuser199011_next">{{ cite magazine | url=https://archive.org/details/AcornUser100-Nov90/page/n73/mode/2up | title=The Next Generation | magazine=Acorn User | date=November 1990 | access-date=24 October 2021 | last1=Brown | first1=Malcolm | pages=72–73 }}</ref>

Two years on from the introduction of CD-ROM products, adoption of the technology was still at a "tentative state", with £8&nbsp;million having been spent on equipment and an estimated 3,000 drives deployed in UK schools. Drive prices had fallen significantly, from around £1,000 to £300 and with a further decline to £200 anticipated. As a significant technology in the delivery of multimedia content, the focus had shifted from merely using CD-ROM as a cheap storage medium for large amounts of graphics and text to aspirations of providing "high-quality, full-screen graphics coupled with hi-fi stereo sound" on CD media, with the principal challenge identified as being able to deliver compressed video that either a computer or a drive could decompress without compromising video quality or introducing incompatibilities between different manufacturers' products.<ref name="acornuser199211_cdrom">{{ cite magazine | url=https://archive.org/details/AcornUser124-Nov92/page/n126/mode/1up | title=Tomorrow's World | magazine=Acorn User | date=November 1992 | access-date=24 October 2021 | last1=Davis | first1=Gordon | pages=123–124 }}</ref>

Acorn's video solution for its own computers was the Replay system, introducing compression formats and associated software for playback and authoring. However, laserdisc technology, which had been used several years earlier by Acorn for interactive video applications, notably in the [[BBC Domesday Project]], was still seen as being a "promising rival" to CD-based video formats, having finally "become successful in multimedia training" and by then "being aimed at well-heeled home video enthusiasts". Reservations about the read-only nature of CD-ROM discs was also seen as a "wounding flaw", leaving users to consider alternatives for convenient bulk storage, with [[magneto-optical drive]]s emerging at this time. Nevertheless, CD-ROM adoption was seen as inevitable, particularly given the format's benefits for holding large amounts of text and making the searching of such text convenient, and with government initiatives having helped to make an estimated 100 titles available for both MS-DOS and RISC OS. The dual-function nature of the media and the ability to use drives to play audio also made such products generally attractive purchases, particularly for home users and with [[Photo CD]] also regarded as an attraction, although the introduction of Philips' [[CD-i]] and Commodore's [[Commodore CDTV|CDTV]] risked a level of confusion in this market as well as presenting another challenge in terms of compatibility for Acorn's own products and technologies.<ref name="acornuser199211_cdrom" />

Acorn would go on to announce Photo CD support in its products in early 1993,<ref name="acornuser199303_kodak">{{ cite magazine | url=https://archive.org/details/AcornUser128-Mar93/page/n11/mode/1up | title=Kodak Makes Deal with Acorn | magazine=Acorn User | date=March 1993 | access-date=6 November 2021 | pages=10 }}</ref> with operating system and application enhancements being delivered by the end of that year. Although the video and memory capabilities of the Archimedes machines were generally unable to take advantage of the higher colour depths or the largest sizes of the scanned images on Photo CD media, the introduction of future hardware from Acorn, featuring the next generation of video controller from ARM and supporting 24-bit colour displays, was anticipated. Support for multi-session CD-ROMs entailed some upgrades to existing SCSI interfaces as well as the use of drives with the appropriate capabilities such as Acorn's own Multimedia Expansion Unit.<ref name="acornuser199311_photocd">{{ cite magazine | url=https://archive.org/details/AcornUser136-Nov93/page/n33/mode/2up | title=Photo Call | magazine=Acorn User | date=November 1993 | access-date=6 November 2021 | last1=Bell | first1=Graham | pages=30–32 }}</ref>

=== Networking capabilities ===

The Archimedes was launched with provision for an optional Econet module to be installed, this module being the same as that used by the Master series.<ref name="acornuser198708_expansion">{{ cite magazine | url=https://archive.org/details/AcornUser061-Aug87/page/n18/mode/1up | title=Plenty of room for expansion | magazine=Acorn User | date=August 1987 | access-date=30 June 2022 | pages=17 }}</ref> Acorn introduced Ethernet connectivity with the launch of the company's R140 Unix workstation, also offering expansion cards for Archimedes models. In 1992, Atomwide also introduced Ethernet cards for the traditional Archimedes expansion bus and for the internal expansion slot in the A3000. Ethernet could be used as faster medium for existing Econet-style networking, or the [[TCP/IP]] [[protocol stack]] could be employed instead. Acorn sought to introduce Econet functionality on top of Internet protocols with its Acorn Universal Networking (AUN) suite of technologies.<ref name="acornuser199204_networking">{{ cite magazine | url=https://archive.org/details/AcornUser117-Apr92/page/n11/mode/1up | title=Faster Networking on the Arc | magazine=Acorn User | date=April 1992 | access-date=30 June 2022 | pages=10 }}</ref>

Numerous vendors offered Ethernet expansion cards, such as Ant Limited (via Atomwide), Digital Services, i-cubed, Oak Solutions, and Risc Developments. Although compatible with AUN, some of the cards offered support for vendor-specific enhancements such as Oak Solutions' ClassNet and Digital Services' NetGain.<ref name="acornuser199407_networking">{{ cite magazine | url=https://archive.org/details/AcornUser144-Jul94/page/n34/mode/1up | title=It's optional | magazine=Acorn User | date=July 1994 | access-date=30 June 2022 | last1=Preston | first1=Geoff | pages=35–37 }}</ref> Other networking approaches were available, including the sharing of hard drives using a [[SCSI]] bus,<ref name="acornuser199102_scsi">{{ cite magazine | url=https://archive.org/details/AcornUser103-Feb91/page/n11/mode/1up | title=SCSI Networks | magazine=Acorn User | date=February 1991 | access-date=30 June 2022 | pages=10 }}</ref> and emerging technologies such as [[Asynchronous Transfer Mode]] were deployed on the Acorn platform, notably in SJ Research's Nexus product.<ref name="acornuser199411_nexus">{{ cite magazine | url=https://archive.org/details/AcornUser148-Nov94/page/n8/mode/1up | title=SJ's ATM secret | magazine=Acorn User | date=November 1994 | access-date=30 June 2022 | pages=9 }}</ref>

=== BBC Micro interfacing and ROM software support ===

As a way of offering continuity with the BBC Micro and the user port, 1&nbsp;MHz bus port and analogue port that were provided by the earlier range of machines, Acorn announced an I/O podule at the launch of the Archimedes, this being fitted with the [[6522]] VIA featured in the BBC range, with the possibility of upgrading the podule to provide a [[MIDI]] port. A ROM podule was also announced with the anticipation that users upgrading from the earlier machines would choose to fit their application and language ROMs in their new machine, these running under the 6502 emulator provided with the operating system.<ref name="acornuser198709_archimedes">{{ cite magazine | url=https://archive.org/details/AcornUser062-Sep87/page/n80/mode/1up | title=Arc de Triomphe | magazine=Acorn User | date=September 1987 | access-date=30 June 2022 | last1=Smith | first1=Bruce | last2=Bell | first2=Graham | pages=79, 81, 83, 85 }}</ref>

In early 1988, Computer Concepts announced its own ROM/RAM podule that was capable of accepting seven chips, each with a maximum capacity of 128&nbsp;KB, supporting the use of installed RAM as "a RAM-disc filing system" with optional battery backup to retain the contents with the machine powered down. The company also announced the availability of its existing BBC Micro productivity suite for use with the board.<ref name="acornuser198802_cc"/> Acorn also released its ROM and I/O podules in the first half of 1988.<ref name="acornuser198805_podules"/> Other companies also offered I/O expansions, such as the Unilab I/O Box 3000 for the A3000 that provided three user ports, analogue port and 1&nbsp;MHz bus port.<ref name="acornuser199107_unilab">{{ cite magazine | url=https://archive.org/details/AcornUser108-Jul91/page/n11/mode/1up | title=I/O A3000 Expansion | magazine=Acorn User | date=July 1991 | access-date=30 June 2022 | pages=10 }}</ref> HCCS and Morley Electronics supplied podules for the A3000 that provided user and analogue ports, with Morley's product also offering an [[I2C]] bus connector ostensibly for the use of subsequent peripherals from the company.<ref name="acornuser199009_augmenting"/>