RISC OS explained

RISC OS
Logo Size:100px
Logo Caption:RISC OS cogwheel logo
Developer:Acorn ComputersOpen-source (version 5)

Proprietary (versions 4 & 6)

Working State:Current
Source Model:Closed source
open source for some versions since 2018
Released:[1]
Latest Release Version:
  • 5.30[2] /
  • 6.20 /
Latest Preview Version:5.31
Marketing Target:Acorn personal computers
Language:English
Programmed In:BBC BASIC, C, C++, assembly language
Update Model:Flash ROM, OTP ROM, or loadable ROM image
Package Manager:PackMan, RiscPkg
Supported Platforms:ARM
Kernel Type:Monolithic
Ui:GUI
License:
Preceded By:MOS
ARX (discontinued)
Website: RISC OS Open
RISCOS
Date:August 2014

RISC OS [4] is a computer operating system originally designed by Acorn Computers Ltd in Cambridge, England. First released in 1987, it was designed to run on the ARM chipset, which Acorn had designed concurrently for use in its new line of Archimedes personal computers. RISC OS takes its name from the reduced instruction set computer (RISC) architecture it supports.

Between 1987 and 1998, RISC OS was included in every ARM-based Acorn computer model, including the Acorn Archimedes line, Acorn's R line (with RISC iX as a dual-boot option), RiscPC, A7000, and prototype models such as the Acorn NewsPad and Phoebe computer. A version of the OS, named NCOS, was used in Oracle Corporation's Network Computer and compatible systems.

After the break-up of Acorn in 1998, development of the OS was forked and continued separately by several companies, including, Pace Micro Technology, and Castle Technology. Since then, it has been bundled with several ARM-based desktop computers such as the Iyonix PC[5] and A9home., the OS remains forked and is independently developed by and the community.

Most recent stable versions run on the ARMv3/ARMv4 RiscPC, the ARMv5 Iyonix,[6] ARMv7 Cortex-A8 processors[7] [8] (such as that used in the BeagleBoard and Touch Book) and Cortex-A9 processors[9] (such as that used in the PandaBoard) and the low-cost educational Raspberry Pi computer.[10] [11] [12] SD card images have been released for downloading free of charge to Raspberry Pi 1, 2, 3, & 4 users with a full graphical user interface (GUI) version[13] and a command-line interface only version (RISC OS Pico, at 3.8 MB).[14]

History

See main article: History of RISC OS.

The first version of RISC OS was originally released in 1987 as Arthur 1.20. The next version,, became and was released in April 1989. RISC OS 3.00 was released with the A5000 in 1991, and contained many new features. By 1996, RISC OS had been shipped on over 500,000 systems.[15]

Acorn officially halted work on the OS in January 1999, renaming themselves Element 14. In March 1999 a new company, RISCOS Ltd, licensed the rights to develop a desktop version of RISC OS from Element 14, and continued the development of RISC OS 3.8, releasing it as RISC OS 4 in July 1999. Meanwhile, Element 14 had also kept a copy of RISC OS 3.8 in house, which they developed into NCOS for use in set-top boxes. In 2000, as part of the acquisition of Acorn Group plc by MSDW Investment, RISC OS was sold to Pace Micro Technology,[16] who later sold it to Castle Technology Ltd.

In May 2001, RISCOS Ltd launched RISC OS Select, a subscription scheme allowing users access to the latest RISC OS 4 updates. These upgrades are released as soft-loadable ROM images, separate to the ROM where the boot OS is stored, and are loaded at boot time. Select 1 was shipped in May 2002, with Select 2 following in November 2002 and the final release of Select 3 in June 2004. In the same month, RISC OS 4.39, dubbed RISC OS Adjust, was released. RISC OS Adjust was a culmination of all the Select Scheme updates to date, released as a physical set of replaceable ROMs for the RiscPC and A7000 series of machines.

Meanwhile, in October 2002, Castle Technology released the Acorn clone Iyonix PC. This ran a 32-bit (in contrast to 26-bit) variant of RISC OS, named RISC OS 5. RISC OS 5 is a separate evolution of RISC OS based upon the NCOS work done by Pace. The following year, Castle Technology bought RISC OS from Pace for an undisclosed sum. In October 2006, Castle announced a shared source license plan, managed by RISC OS Open Limited, for elements of RISC OS 5.

In October 2018, RISC OS 5 was re-licensed under the Apache 2.0 license.[17]

In December 2020, the source code of RISC OS 3.71 was leaked to The Pirate Bay.

Supported hardware

Versions of RISC OS run or have run on the following hardware.

Machine !! style="vertical-align:bottom;" rowspan="2"
ARM architecture !Introduced Acorn version RISCOS Ltd version Castle Technology, RISC OS Open version
First Last First Last First Latest
ARM with 26-bit program counter
ARMv2 1987–1992 0.20 3.1x
ARM with 26- & 32-bit program counter
ARMv3 / v4 1994[18] 3.50 3.71 4.00 6.20[19] 5.15 5.30[20] /5.31
ARMv3 1995[21] 1997[22] 3.60
Acorn Phoebe (cancelled) ARMv4 1998 3.80 (Ursula)
MicroDigital Medi[23] ARMv3 1998[24] 3.71 4.02 6.20
MicroDigital Mico 1999[25] 4.03 4.39
RiscStation R7500 1999[26] 4.03 4.39
Castle Kinetic RiscPC ARMv4 2000[27] 4.03 6.20 5.19[28] 5.30/5.31
2003[29] 4.03[30] 4.39
Advantage Six A75 ARMv3 2004[31] 4.39[32]
ARM with 32-bit program counter
ARMv5TE 2002 5.01 5.30[33] /5.31
Advantage Six A9 (Home/RM/Loc) ARMv5TE 2005 4.42
ARMv7-A 2008 5.15 5.30[34] /5.31
IGEPv2[35] 2009
?
2009
2010 5.17[36]
PandaBoard[37] 2011 5.17 5.30/5.31
Raspberry Pi (1 - 4 and compatible)[38] [39] [40] ARMv6, v7-A, v8-A 2012 5.19 5.30/5.31
IGEPv5[41] ARMv7-A 2014 5.23 5.30/5.31
Wandboard Quad[42] [43] 2015 5.21 5.31
Titanium[44] 5.23 5.30/5.31
Pinebook[45] ARMv8-A 2017 5.27 5.31

RISC OS Open Limited adopted[46] the 'even numbers are stable' version numbering scheme post version 5.14, hence some table entries above include two latest releases – the last stable one and the more recent development one.

A special cut down RISC OS Pico (for 16MiB cards and larger) styled to start up like a BBC Micro was released for BASIC's 50th anniversary.[47]

RISC OS has also been used by both Acorn and Pace Micro Technology in various TV connected set-top boxes, sometimes referred to instead as NCOS.

RISC OS can also run on a range of computer system emulators that emulate the earlier Acorn machines listed above.

RISC OS capable hardware emulators
Emulator Machines emulated Host platforms supported Latest release
!A310Emu[48] Archimedes RISC OS 0.59
Archie[49] 0.9 – 10 February 2001
ArchiEmu[50] RISC OS 0.53.3 – 7 December 2014
ArcEm[51] Windows, Linux, macOS, RISC OS 1.50.1 – 18 December 2015
Arculator[52] Windows, Linux 2.2 – 24 June 2023
Windows 1.4
Red Squirrel[53] Archimedes, Risc PC, A7000 0.6 – 28 October 2002
RPCEmu[54] Risc PC, A7000, Phoebe 0.9.4 – 30 October 2021
VirtualRPCRisc PC Windows, macOS 5 September 2014[55]

Features

OS core

The OS is single-user and employs cooperative multitasking (CMT).[56] While most current desktop OSes use preemptive multitasking (PMT) and multithreading, remains with a CMT system. By 2003, many users had called for the OS to migrate to PMT.[57] The OS memory protection is not comprehensive.[58] [59]

The core of the OS is stored in ROM, giving a fast bootup time and safety from operating system corruption. RISC OS 4 and 5 are stored in of flash memory, or as a ROM image on SD Card on single board computers such as the Beagleboard or Raspberry Pi, allowing the operating system to be updated without having to replace the ROM chip. The OS is made up of several modules. These can be added to and replaced, including soft-loading of modules not present in ROM at run time and on-the-fly replacement. This design has led to OS developers releasing rolling updates to their versions of the OS, while third parties are able to write OS replacement modules to add new features. OS modules are accessed via software interrupts (SWIs), similar to system calls in other operating systems.

Most of the OS has defined application binary interfaces (ABIs) to handle filters and vectors. The OS provides many ways in which a program can intercept and modify its operation. This simplifies the task of modifying its behaviour, either in the GUI, or deeper. As a result, there are several third-party programs which allow customising the OS look and feel.

File system

The file system is volume-oriented: the top level of the file hierarchy is a volume (disc, network share) prefixed by the file system type. To determine file type, the OS uses metadata instead of file extensions. Colons are used to separate the file system from the rest of the path; the root is represented by a dollar ($) sign and directories are separated by a full stop (.). Extensions from foreign file systems are shown using a slash (example.txt becomes example/txt).[60] For example, ADFS::HardDisc4.$ is the root of the disc named HardDisc4 using the Advanced Disc Filing System (ADFS) file system. filetypes can be preserved on other systems by appending the hexadecimal type as ',xxx' to filenames.[61] When using cross-platform software, filetypes can be invoked on other systems by naming appending '/[extension]' to the filename under .

A file system can present a file of a given type as a volume of its own, similar to a loop device. The OS refers to this function as an image filing system. This allows transparent handling of archives and similar files, which appear as directories with some special properties. Files inside the image file appear in the hierarchy underneath the parent archive. It is not necessary for the archive to contain the data it refers to: some symbolic link and network share file systems put a reference inside the image file and go elsewhere for the data.

The file system abstraction layer API uses 32-bit file offsets, making the largest single file 4 GiB (minus 1 byte) long. However, prior to RISC OS 5.20 the file system abstraction layer and many RISC OS-native file systems limited support to 31 bits (just under 2 GiB) to avoid dealing with apparently negative file extents when expressed in two's complement notation.

File formats

See main article: List of RISC OS filetypes. The OS uses metadata to distinguish file formats. Some common file formats from other systems are mapped to filetypes by the MimeMap module.[62]

Kernel

The RISC OS kernel is single-tasking and controls handling of interrupts, DMA services, memory allocation and the video display; the cooperative multi-tasking is provided by the WindowManager module.

Desktop

The WIMP interface is based on a stacking window manager and incorporates three mouse buttons[63] (named Select, Menu and Adjust), context-sensitive menus, window order control (i.e. send to back) and dynamic window focus (a window can have input focus at any position on the stack). The icon bar (Dock) holds icons which represent mounted disc drives, RAM discs, running applications, system utilities and docked: files, directories or inactive applications. These icons have context-sensitive menus and support drag-and-drop operation. They represent the running application as a whole, irrespective of whether it has open windows.

The GUI functions on the concept of files. The Filer, a spatial file manager, displays the contents of a disc. Applications are run from the Filer view and files can be dragged to the Filer view from applications to perform saves, rather than opening a separate 'Save' dialog box where the user must navigate to a location already visible in the Finder. In addition, files can be directly transferred between applications by dragging a save icon into another application's window.

Application directories are used to store applications. The OS differentiates them from normal directories through the use of an exclamation mark (also called a pling or shriek) prefix. Double-clicking on such a directory launches the application rather than opening the directory. The application's executable files and resources are contained within the directory, but normally they remain hidden from the user. Because applications are self-contained, this allows drag-and-drop installing and removing.

The Style Guide encourages a consistent look and feel across applications. This was introduced in and specifies application appearance and behaviour. Acorn's own main bundled applications were not updated to comply with the guide until 's Select release in 2001.[64]

Font manager

RISC OS was the first operating system to provide scalable anti-aliased fonts.[65] [66] [67] [68] Anti-aliased fonts were already familiar from Arthur, and their presence in RISC OS was confirmed in an early 1989 preview,[69] featuring in the final RISC OS 2 product, launched in April 1989.[70]

A new version of the font manager employing "new-style outline fonts" was made available after the release of RISC OS,[71] offering full support for the printing of scalable fonts, and was provided with Acorn Desktop Publisher.[72] It was also made available separately and bundled with other applications.[73] This outline font manager provides support for the rendering of font outlines to bitmaps for screen and printer use, employing anti-aliasing for on-screen fonts, utilising sub-pixel anti-aliasing and caching for small font sizes.[74] At the time of the introduction of Acorn's outline font manager, the developers of rival desktop systems were either contemplating or promising outline font support for still-unreleased products such as Macintosh System 7 and OS/2 version 2.[75]

Since 1994, in RISC OS 3.5, it has been possible to use an outline anti-aliased font in the WindowManager for UI elements, rather than the bitmap system font from previous versions.[76] RISC OS 4 does not support Unicode but "RISC OS 5 provides a Unicode Font Manager which is able to display Unicode characters and accept text in UTF-8, UTF-16 and UTF-32. Other parts of the RISC OS kernel and core modules support text described in UTF-8."[77]

Support for the characters of RISC OS (and some other historic computers) was added to Unicode 13.0 (in 2020).[78]

Bundled applications

See main article: List of RISC OS bundled applications. is available in several distributions, all of which include a small standard set of desktop applications, but some of which also include a much wider set of useful programs. Some of those richer distributions are freely available, some are paid for.

Backward compatibility

Limited software portability exists with subsequent versions of the OS and hardware. Single-tasking BBC BASIC applications often require only trivial changes, if any. Successive OS upgrades have raised more serious issues of backward compatibility for desktop applications and games.[79] Applications still being maintained by their author(s) or others have sometimes historically been amended to provide compatibility.

The introduction of the RiscPC in 1994 and its later StrongARM upgrade raised issues of incompatible code sequences and proprietary squeezing (data compression). Patching of applications for the StrongARM was facilitated and Acorn's UnsqueezeAIF software unsqueezed images according to their AIF header.[80] The incompatibilities prompted release by The ARM Club of its Game On![81] [82] and StrongGuard software.[83] [84] They allowed some formerly incompatible software to run on new and upgraded systems. The version of the OS for the A9home prevented the running of software without an AIF header (in accord with Application Note 295)[85] to stop "trashing the desktop".[86]

The Iyonix PC and A9home (custom) saw further software incompatibility because of the deprecated addressing modes. Most applications under active development have since been rewritten.[87] [88] [89] Static code analysis to detect -only sequences can be undertaken using ARMalyser.[90] Its output can be helpful in making 32-bit versions of older applications for which the source code is unavailable.[91] [92] Some older 26-bit software can be run without modification using the Aemulor emulator.

Additional incompatibilities were introduced with newer ARM cores, such as ARMv7 in the BeagleBoard and ARMv8 in the . This includes changes to unaligned memory access in ARMv6/v7 and removal of the SWP instructions in ARMv8.[93]

See also

External links

Notes and References

  1. copyright notice Arthur 1.20 (25 September 1987)
  2. Web site: RISC OS 5.30 now available . 2024-04-30 . Revill . Steve . 27 April 2024 . .
  3. https://www.riscosopen.org/news/articles/2018/10/22/risc-os-is-open-for-business RISC OS is open for business!
  4. News: RISC OS . ISV Department news from Acorn . Acorn Computers Limited . May 1989 . 14 . 2021-02-14 . 2 . It is RISC OS (pronounced risk oh ess, not risk oss) . 21 May 2021 . https://web.archive.org/web/20210521002744/http://chrisacorns.computinghistory.org.uk/docs/Acorn/DN/Acorn_DevNL14.pdf . live .
  5. Acorn Computers Ltd . Acorn announces distribution deal with Castle Technology for RISC based products . 12 October 1998 . 2011-01-06 . (October 12th 1998), Cambridge, UK-Acorn announced today that it has completed negotiations with Castle Technology for them to distribute Acorn products. . https://web.archive.org/web/19990506180305/http://www.acorn.co.uk/acorn/news/press/castle.html . 6 May 1999.
  6. Web site: RISC OS 5 features . 2011-01-31 . Iyonix Ltd . All IYONIX pcs ship with RISC OS 5 in flash ROM. . dead . https://web.archive.org/web/20101110111706/http://www.iyonix.com/iyonix/features/osfeatures.shtml . 10 November 2010.
  7. Web site: Snaps leak of RISC OS5 on BeagleBoard . https://web.archive.org/web/20090519184833/http://www.theinquirer.net/inquirer/news/1051924/snaps-leak-risc-os5-beagleboard . unfit . 19 May 2009 . . 27 April 2009 . 2011-06-28 . Farrell . Nick . A snap of an RISC OS 5, running on a BeagleBoard device powered by a 600MHz ARM Cortex-A8 processor with a built-in graphics chip, has tipped up on the world wide wibble. The port developed by Jeffrey Lee is a breakthrough for the shared-source project because it has ported the OS without an army of engineers..
  8. Web site: Cortex-A8 port status . 2011-01-31 . . [The port includes] a modified version of the RISC OS kernel containing support for (all) Cortex-A8 CPU cores. . 26 October 2021 . https://web.archive.org/web/20211026212426/https://www.riscosopen.org/hub/account/login . live .
  9. Web site: RISC OS 5.22 stable is now available . 2015-04-25 . Revill . Steve . 25 April 2015 . RISC OS Open.
  10. Web site: Newsround . . 17 October 2011 . Lee . Jeffrey . 4 January 2016 . https://web.archive.org/web/20160104182418/http://www.iconbar.com/articles/Newsround/index1271.html . live .
  11. Web site: Raspberry Pi To Embrace RISC OS . . 31 October 2011 . 1 November 2011 . Holwerda . Thom . 4 January 2016 . https://web.archive.org/web/20160104182418/http://www.osnews.com/story/25276/Raspberry_Pi_To_Embrace_RISC_OS . live .
  12. News: The London show 2011 . . December 2011 . Dewhurst . Christopher . 23 . 3 . 3.
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  15. Web site: ART – Acorn RISC OS. acorn.chriswhy.co.uk. 8 July 2011. 27 May 2013. https://web.archive.org/web/20130527220851/http://acorn.chriswhy.co.uk/docs/Acorn/ART/ART_DS013_AcornRISCOS.pdf. live.
  16. News: ARM denies role in Acorn dismemberment . . 24 April 1999 . 31 January 2021 . Cullen . Drew .
  17. Web site: Roughly 30 years after its birth at UK's Acorn Computers, RISC OS 5 is going open source. Richard. Speed. www.theregister.com. 26 October 2021. 23 September 2021. https://web.archive.org/web/20210923185001/https://www.theregister.com/2018/10/23/risc_os_open_source/. live.
  18. Web site: Chris's Acorns: Risc PC Computers. chrisacorns.computinghistory.org.uk. 22 July 2015. 21 October 2017. https://web.archive.org/web/20171021213428/http://chrisacorns.computinghistory.org.uk/Computers/RiscPCComputers.html. live.
  19. Web site: RISC OS Six Frequently Asked Questions. https://archive.today/20121208135752/http://select.riscos.com/RISCOS6/faq.html . 8 December 2012.
  20. Web site: RISC OS Open: RiscPC. www.riscosopen.org. 25 April 2015. 11 April 2015. https://web.archive.org/web/20150411175939/https://www.riscosopen.org/content/downloads/riscpc. live.
  21. Web site: Chris's Acorns: Acorn A7000. computinghistory.org.uk. 22 July 2015. 11 October 2015. https://web.archive.org/web/20151011194352/http://chrisacorns.computinghistory.org.uk/Computers/A7000.html. live.
  22. Web site: Chris's Acorns: Acorn A7000+. computinghistory.org.uk. 22 July 2015. 11 October 2015. https://web.archive.org/web/20151011194330/http://chrisacorns.computinghistory.org.uk/Computers/A7000+.html. live.
  23. repackaged A7000+
  24. Web site: Chris's Acorns: MicroDigital. computinghistory.org.uk. 22 July 2015. 22 July 2015. https://web.archive.org/web/20150722224655/http://chrisacorns.computinghistory.org.uk/AfterAcorn/Microdigital.html#Medi. live.
  25. Web site: Chris's Acorns: MicroDigital. computinghistory.org.uk. 22 July 2015. 22 July 2015. https://web.archive.org/web/20150722224655/http://chrisacorns.computinghistory.org.uk/AfterAcorn/Microdigital.html#Mico. live.
  26. Web site: Chris's Acorns: RISC OS After Acorn. computinghistory.org.uk. 22 July 2015. 11 October 2015. https://web.archive.org/web/20151011194254/http://chrisacorns.computinghistory.org.uk/AfterAcorn.html#RiscStation. live.
  27. Web site: The Icon Bar: Castle reveal Kinetic to the press. iconbar.com. 23 February 2011. 16 July 2012. https://web.archive.org/web/20120716211137/http://www.iconbar.com/forums/viewthread.php?newsid=918. live.
  28. Web site: Bugs and sources . RISC OS Open . 2013-03-28 . 2013-09-02 . 13 April 2015 . https://web.archive.org/web/20150413035910/https://www.riscosopen.org/viewer/revisions/logs?ident=1364507316-018164.html . live .
  29. Web site: Omega production saga continues – Drobe.co.uk archives. drobe.co.uk. 8 February 2012. 16 March 2012. https://web.archive.org/web/20120316220842/http://www.drobe.co.uk/article.php?id=973. live.
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  33. Web site: RISC OS Open: Iyonix. riscosopen.org. 25 April 2015. 11 April 2015. https://web.archive.org/web/20150411180000/https://www.riscosopen.org/content/downloads/iyonix. live.
  34. Web site: RISC OS Open: BeagleBoard. riscosopen.org. 25 April 2015. 11 April 2015. https://web.archive.org/web/20150411175957/https://www.riscosopen.org/content/downloads/beagleboard. live.
  35. Web site: RISC OS on IGEPv2 . 24 January 2010 . 19 September 2023 .
  36. Web site: RISC OS Open: Forum: Let's get started with a Pandora port. riscosopen.org. 10 July 2012. 19 September 2014. https://web.archive.org/web/20140919225512/https://www.riscosopen.org/forum/forums/5/topics/166?page=14. live.
  37. Web site: Have I Got Old News For You . . 2 August 2011 . 28 September 2011 . Lee . Jeffrey . [...] Willi Theiss has recently announced that he's been working on a port of RISC OS to the PandaBoard [...] . 12 June 2012 . https://web.archive.org/web/20120612074011/http://www.iconbar.com/articles/Have_I_Got_Old_News_For_You/index1268.html . live .
  38. Web site: raspberrypi.org. 1 November 2011. 29 February 2012. https://web.archive.org/web/20120229180108/http://www.raspberrypi.org/?page_id=43. dead.
  39. Web site: Raspberry Pi B+ . 15 July 2014 . 13 August 2014 . 25 July 2014 . https://web.archive.org/web/20140725122155/https://www.riscosopen.org/news/articles/2014/07/15/raspberry-pi-model-b . live .
  40. Web site: Raspberry Pi 3 . 29 February 2016 . 26 March 2016 . 7 April 2016 . https://web.archive.org/web/20160407201218/https://www.riscosopen.org/forum/forums/1/topics/3943?page=2#posts-50397 . live .
  41. Web site: RISC OS on IGEPv5 . 9 September 2014 . 9 September 2014 . 11 April 2015 . https://web.archive.org/web/20150411204755/https://www.riscosopen.org/forum/forums/9/topics/2803 . live .
  42. Web site: ARMX6 formally announced at last . RISCOSitory . 1 February 2015 . Hudd . Vince M. . Soft Rock Software . 1 November 2015 . [...] The heart of the machine is a Freescale i.MX 6 series processor [...] . 4 January 2016 . https://web.archive.org/web/20160104182418/http://www.riscository.com/2015/armx6-formally-announced/ . live .
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  45. Web site: Pinebook port . 8 September 2023 . 19 September 2023 .
  46. Web site: Stable release criteria . 12 January 2017 . 12 January 2017 . 9 November 2018 . https://web.archive.org/web/20181109020018/https://www.riscosopen.org/content/documents/stable-releases . live .
  47. Web site: Happy birthday, BASIC. 5 January 2014. 8 May 2018. 9 November 2018. https://web.archive.org/web/20181109020010/https://www.riscosopen.org/news/articles/2014/05/01/happy-birthday-basic. live.
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  50. Web site: Tellima . 2015-12-13 . 22 December 2015 . https://web.archive.org/web/20151222081521/http://www.tellima.nl/riscos/ . live .
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  52. Web site: Arculator – The Acorn Archimedes Emulator . B-em.bbcmicro.com . 2019-09-11 . 21 June 2013 . https://web.archive.org/web/20130621075124/http://b-em.bbcmicro.com/arculator/ . live .
  53. Web site: Red Squirrel Acorn Archimedes Emulator . Redsquirrel.fsnet.co.uk . 2013-09-02 . 27 December 2005 . https://web.archive.org/web/20051227213827/http://www.redsquirrel.fsnet.co.uk/redsquirrel.html . live .
  54. Web site: RPCEmu . Marutan.net . 2017-11-07 . 16 March 2013 . https://web.archive.org/web/20130316043123/http://www.marutan.net/rpcemu/ . live .
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