Editing RISC iX (section)

== Hardware ==
[[File:Acorn-A680-R140.jpg|thumb|Acorn A680 and Acorn R140]]

According to documentation concerning RISC iX 1.2 availability, the operating system could be used on the R140, R225 and R260, being pre-installed on the R260, accessible via a [[fileserver]] (such as an R260) on the R225, and as an upgrade from RISC iX 1.15 or earlier on the R140. The A540, being practically identical to the R260,<ref name="acornuser199011">{{cite news |url=https://archive.org/details/AcornUser100-Nov90/page/n22/mode/1up |title=Five's Alive |work=Acorn User |date=November 1990 |access-date=22 October 2020 |last1=James |first1=Paul |last2=Bell |first2=Graham |pages=21 |quote=In essence, the machine is identical to the R260 Unix workstation, but comes without Unix and without the built-in Ethernet of the latter machine.}}</ref> could support RISC iX as delivered, whereas A400-series machines required an Acorn SCSI card, with older A400-series machines also needing a memory controller upgrade and "all the appropriate field change orders" to have been performed. A300-series machines and the A3000 were not supported, largely due to potential compatibility issues with upgrades needed to bring these machines up to the required specification, in addition to operating temperature considerations with the A3000.<ref name="acorn_a252unix">{{cite tech report |url=http://chrisacorns.computinghistory.org.uk/docs/Acorn/Misc/a252unix.txt |title=RISCiX 1.2 Upgrade Products |publisher=Acorn Computers Limited |access-date=10 October 2020}}</ref> Subsequent Archimedes machines, such as the A5000 and A30x0 models, were introduced without any prominent indication of RISC&nbsp;iX compatibility, although the A5000 expansion hardware was designed to support the same form of expansion card interrupt management as the A540, R-series and A400/1-series, specifically to be able to support {{nowrap|RISC iX}}.<ref name="acorn_enhanced_expansion">{{ cite tech report | url=https://archive.org/details/manualzilla-id-7394047/page/5/mode/1up | title=Acorn Enhanced Expansion Card Specification | publisher=Acorn Computers Limited | date=July 1994 | access-date=30 December 2023 | issue=5 | pages=5 | quote=Some variants of the computer (Archimedes 400/1, 540, A5000 and R-Series) have extra logic on the backplane PCB, for expansion card interrupt management. The default/power on state of the logic leaves expansion card interrupts enabled, i.e. the logic can be ignored and the system will behave identically to the A300 and early A440 models. Two functions are added by the extra logic, a mask register and a status register. The logic is fitted to support RISC iX. }}</ref>

Several machines were designed specifically to run RISC iX.

=== M4 ===

An unreleased machine, built internally by Acorn for the development of RISC iX. Reputedly only two or three were built and one of them has subsequently been destroyed. All known examples are owned by [[The National Museum of Computing]].<ref name="chris_riscix_computers">{{ cite web | url=http://chrisacorns.computinghistory.org.uk/RISCiXComputers.html | title=RISC iX Computers | website=Chris's Acorns | date=2 May 2014 | access-date=23 January 2025 }}</ref>

=== A680 Technical Publishing System ===

Prototyped for an Olivetti product but unreleased, the A680 contained an [[ARM2]] processor, 8&nbsp;[[Megabyte|MB]] [[random-access memory|RAM]], a 70&nbsp;MB hard drive running from an onboard [[SCSI controller]], and either a 40&nbsp;MB cartridge tape drive or a single 2&nbsp;MB floppy drive. Up to four "podule" expansion cards could be fitted, although one slot was occupied by the laser beam printer (LBP) expansion card supporting a directly driven low-cost [[laser printer]] as an alternative to a [[PostScript]] printer connected via the serial port.<ref name="ATPS_TRM_part1">{{cite book |url=http://chrisacorns.computinghistory.org.uk/docs/Acorn/Manuals/Acorn_TechnicalPublishingSystemTRMPt1.pdf |title=Acorn Technical Publishing System Technical Reference Manual |publisher=Acorn Computers Limited |date=July 1988 |access-date=11 February 2021 |issue=B}}</ref>{{rp|pages=2}} The system was meant to run [[Adobe FrameMaker|Frame Technology's FrameMaker]] under the "Acorn UNIX" operating system and NeWS graphical environment.<ref name="ATPS_TRM_part1" />{{rp|pages=4}} To support 8&nbsp;MB of RAM, dual memory controller (MEMC) units were employed.<ref name="ATPS_TRM_part1" />{{rp|pages=10|quote=Two memory sizes are supported: 4 Mbyte (single MEMC), or 8 Mbyte (dual MEMC).}}

The A680 was reportedly the first target for RISC iX and differed in certain ways from the Archimedes and R-series models. For instance, no other machine from [[Acorn Computers]] featured integrated [[SCSI]].<ref name="chris_riscix_computers"/> However, it is rumoured that overheating from the SCSI controller was one reason for the machine to never be released.{{citation needed|date=February 2021}}

=== R140 ===

Based on the A440/1, the R140 uses the same 8&nbsp;[[Megahertz|MHz]] ARM2 processor and 4&nbsp;MB RAM, also providing a 60&nbsp;MB [[ST506]] [[hard drive]], with the option of adding a second hard drive using the same internal controller. A [[SCSI]] adaptor was available (priced at £299 plus VAT) for other storage peripherals. Since the hardware is based on the Archimedes series, Acorn's podule expansions could be added, although appropriate drivers would have needed to be written.<ref name="acornuser198912" />{{rp|pages=47|quote=All the Archimedes podules are electrically compatible but need a Unix software driver to work with the R140.}}

At the time of initial release in 1989, the cost of the R140 was £3,500 for a standalone workstation without Ethernet connectivity. For the additional cost of the Ethernet expansion (£449 plus VAT), a network-capable workstation could be configured. A floating point expansion card<ref name="chrisacorns-we32206">{{cite web |url=http://chrisacorns.computinghistory.org.uk/32bit_UpgradesA2G/Acorn_AKA20_WE32206FPCoPro.html |title=Acorn AKA20 We32206 Floating Point Co-Processor |website=Chris's Acorns |date=2 May 2014 |access-date=27 August 2021}}</ref> based on the WE32206 could also be added (priced at £599 plus VAT).<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> A discount introduced at the start of 1990 offered the R140 bundled with Ethernet expansion and either a 14-inch colour monitor with PC emulation software or a 19-inch monochrome monitor for £2999 plus VAT.<ref name="acornuser199002">{{cite news |url=https://archive.org/details/AcornUser091-Feb90/page/n8/mode/1up |title=Cheap Workstation |work=Acorn User |date=February 1990 |access-date=24 December 2020 |pages=7}}</ref>

Supplied with RISC&nbsp;OS&nbsp;2 in ROM, the machine would boot that OS then could either automatically boot RISC iX totally removing RISC OS from memory or continue running RISC&nbsp;OS{{snd}}optionally being rebooted into RISC&nbsp;iX at any time.<ref name="pcw198903">{{cite news |url=http://chrisacorns.computinghistory.org.uk/docs/Mags/PCW/PCW_Mar89_R140.pdf |title= Acorn R140 |work=Personal Computer World |date=March 1989 |access-date=23 October 2020 |last1=Redfern |first1=Andy |page=128 |quote=On switching the machine on you are booted almost instantly into RISC OS. [...] Clicking on the Unix icon activates a dialogue box asking if you really want to go into Unix or not. By clicking on the middle of this box a number of parameters can be set up. For example, you can disable RISC OS completely so that next time you switch the machine on it boots straight into Unix, or you can specify a slow boot which performs all the disk and file checking.}}</ref>

An ordinary A440/1 with at least 4&nbsp;MB RAM and a suitable hard drive could also run RISC iX.<ref name="acorn_a252unix" />

=== R260 ===

Based on the A540,<ref name="A500_R200_service">{{cite book |url=http://chrisacorns.computinghistory.org.uk/docs/Acorn/Manuals/Acorn_A500R200SM.pdf |title=Acorn Archimedes 500 series Acorn R200 series Service Manual |publisher=Acorn Computers Limited |date=June 1991 |isbn=185250093X |pages=vi}}</ref> the R260 originally contained a 30&nbsp;MHz [[ARM3]] processor, 8&nbsp;MB RAM (upgradable to 16&nbsp;MB) SCSI adapter and a 100&nbsp;MB<ref name="acornuser199008" /><ref name="pcw199008" /> or 120&nbsp;MB<ref name="AcornR260">{{cite book |url=http://chrisacorns.computinghistory.org.uk/docs/Acorn/Brochures/Acorn_APP480_R260.pdf |title=Acorn R260 |publisher=Acorn Computers Limited |edition=1 |date=August 1992 |access-date=8 September 2020 |pages=2}}</ref> SCSI hard drive (typically a [[Conner Peripherals|Conner CP30100]]). It booted in the same style as the earlier R140, but was normally configured for customers to boot straight into RISC iX.<ref name="byte199012">{{cite news |url=https://vintagecomputers.sdfeu.org/mags/byte/Acorn_R260_review.pdf |title=A RISC Workstation from Acorn |work=Byte |date=December 1990 |last1=Pountain |first1=Dick |pages=72IS–15 |quote=As normally delivered to customers, though, the R260 boots straight into RISCiX multi-user mode; you never see RISC OS. To enter RISC OS, you must log out of Unix by typing halt -RISCOS.}}</ref> The machine was supplied with an [[Ethernet]] adapter.

The system was released in 1990 priced at £3995 plus VAT,<ref name="acorn_news16">{{cite news |url=http://chrisacorns.computinghistory.org.uk/docs/Acorn/NL/Acorn_NewsIss16.pdf |title=Acorn Newsletter |date=1990 |issue=16 |publisher=Acorn Computers Limited |pages=1}}</ref> having been announced with a price of £5000 plus VAT.<ref name="acornuser199008" /> A [[floating-point unit|floating point accelerator]] or "arithmetic co-processor", the FPA10, was made available in 1993 for the R260, as well as for the A540 and A5000 machines, priced at £99 plus VAT. These machines were designed to support the FPA device via a dedicated socket on the processor card (or, in the case of the A5000, on the motherboard), and 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=1993 |access-date=7 April 2021}}</ref>

A similarly configured A540 could run RISC iX.<ref name="acorn_a252unix" /> Production of the A540 and R260 was discontinued in mid-1993.<ref name="acornsn_issue76">{{cite news |url=http://chrisacorns.computinghistory.org.uk/docs/Acorn/SN/Acorn_SalesNews76.pdf |title=Sales News |publisher=Acorn Computers Limited |date=5 July 1993 |issue=76 |access-date=14 February 2021}}</ref>

=== R225 ===

The R225 was a [[diskless workstation|diskless]] version of the R260. It required a network file server or an R260 to boot.<ref name="acorn_a252unix" /> The system was released alongside the R260 priced at £1995 plus VAT,<ref name="acorn_news16" /> having been announced with a price of £3000 plus VAT.<ref name="acornuser199008" />