NationMaster - Encyclopedia: RISC OS

RISC OS is a computer operating system originally created by British manufacturer Acorn Computers. Image File history File links This is a lossless scalable vector image. ... Image File history File links Download high resolution version (1024x768, 264 KB) Summary Default RISC OS 4 desktop, showing the filer, !Paint, !Edit and a task window running BBC Basic. ... A website (alternatively, Web site) is a collection of Web pages, images, videos and other digital assets that is hosted on a Web server, usually accessible via the Internet or a LAN. A Web page is a document, typically written in HTML, that is almost always accessible via HTTP, a... It has been suggested that software publisher be merged into this article or section. ... A software developer is a person who is concerned with one or more facets of the software development process, a somewhat broader scope of computer programming or a specialty of project managing. ... RISCOS Ltd was a UK limited company created in 1999 to continue user-focused development of the RISC OS operating system after the collapse of Acorn. ... Castle Technology Ltd. ... The text below is generated by a template, which has been proposed for deletion. ... Shared source is a type of licensing program that allows controlled access to full or limited amounts of product source code. ... April 28 is the 118th day of the year (119th in leap years) in the Gregorian calendar. ... shelby was here 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... is the 287th day of the year (288th in leap years) in the Gregorian calendar. ... For the Manfred Mann album, see 2006 (album). ... The ARM architecture (previously, the Advanced RISC Machine, and prior to that Acorn RISC Machine) is a 32-bit RISC processor architecture developed by ARM Limited that is widely used in a number of embedded designs. ... The user interface is the part of a system exposed to users. ... A graphical user interface (GUI) is a type of user interface which allows people to interact with a computer and computer-controlled devices which employ graphical icons, visual indicators or special graphical elements called widgets, along with text labels or text navigation to represent the information and actions available to... This article or section does not adequately cite its references or sources. ... A software license is a legal agreement which may take the form of a proprietary or gratuitous license as well as a memorandum of contract between a producer and a user of computer software. ... Proprietary software is software with restrictions on using, copying and modifying as enforced by the proprietor. ... // An operating system (OS) is a set of computer programs that manage the hardware and software resources of a computer. ... forever . ...

The operating system takes its name from the RISC architecture used on supported systems. Reduced Instruction Set Computer (RISC), is a microprocessor CPU design philosophy that favors a smaller and simpler set of instructions that all take about the same amount of time to execute. ...

Features

Read-only memory (usually known by its acronym, ROM) is a class of storage media used in computers and other electronic devices. ... The three-letter acronym MIB may refer to any of several concepts: Management information base, a computing information repository used (for example) by SNMP In marbles, any marble, but esp. ... RISCOS Ltd was a UK limited company created in 1999 to continue user-focused development of the RISC OS operating system after the collapse of Acorn. ... An application programming interface (API) is a source code interface that a computer system or program library provides to support requests for services to be made of it by a Length. ... Microsoft Windows is the name of several families of proprietary software operating systems by Microsoft. ... It has been suggested that this article or section be merged into Computer_multitasking#Cooperative_multitasking. ... Pre-emption as used with respect to operating systems means the ability of the operating system to preempt or stop a currently scheduled task in favour of a higher priority task. ... In computing, multitasking is a method by which multiple tasks, also known as processes, share common processing resources such as a CPU. In the case of a computer with a single CPU, only one task is said to be running at any point in time, meaning that the CPU is... A thread in computer science is short for a thread of execution. ... Memory protection is a system that prevents one process from corrupting the memory of another process running on the same computer at the same time. ... The Advanced Disc Filing System (ADFS) is a computing file system particular to the Acorn computer range and RISC OS based successors. ... an exclamation mark An exclamation mark, exclamation point or bang, !, is usually used after an interjection or exclamation to indicate strong feeling. ... In humanâ€“computer interaction, WIMP stands for window, icon, menu, pointing device, denoting a style of interaction using these elements. ... Windows 3. ... System 7 (codenamed Big Bang) was a version of Mac OS, the operating system of the Apple Macintosh computer. ... Drag-and-drop refers to the act of (or support for the act of) clicking on a virtual object and dragging it to, or onto, another virtual object. ... In digital signal processing, anti-aliasing is the technique of minimizing the distortion artifacts known as aliasing when representing a high-resolution signal at a lower resolution. ...

Bundled applications

Applications bundled with RISC OS vary slightly between versions, but usually include the following core apps:

This example shows an image with a portion greatly enlarged, in which the individual pixels are rendered as little squares and can easily be seen. ... Example showing effect of vector graphics versus raster graphics. ... Notepad is the standard text editor for Microsoft Windows A text editor is a piece of computer software for editing plain text. ...

Early years

RISC OS was designed in Cambridge, England by Acorn for the 32-bit ARM-based Acorn Archimedes and released in its first version in 1987 as the Arthur operating system. A screenshot of Arthurs GUI desktop and its bundled accessory applications Arthur is an early GUI operating System (OS) that was used on Acorn ARM-cpu-based computers from about 1987 until the much-superior RISC OS 2 was completed and made available in April 1989. ... The Acorn Arthur operating system desktop This is a screenshot of copyrighted computer software. ... The Acorn Arthur operating system desktop This is a screenshot of copyrighted computer software. ... Geography Status City (1951) Region East of England Admin. ... Motto (French) God and my right Anthem No official anthem - the United Kingdom anthem God Save the Queen is commonly used England() â€“ on the European continent() â€“ in the United Kingdom() Capital (and largest city) London (de facto) Official languages English (de facto) Unified - by Athelstan 927 AD Area - Total 130... Acorn Computers Ltd. ... 32-bit is a term applied to processors, and computer architectures which manipulate the address and data in 32-bit chunks. ... The ARM architecture (previously, the Advanced RISC Machine, and prior to that Acorn RISC Machine) is a 32-bit RISC processor architecture developed by ARM Limited that is widely used in a number of embedded designs. ... This article or section does not cite its references or sources. ... A screenshot of Arthurs GUI desktop and its bundled accessory applications Arthur is an early GUI operating System (OS) that was used on Acorn ARM-cpu-based computers from about 1987 until the much-superior RISC OS 2 was completed and made available in April 1989. ...

RISC OS 2

RISC OS was a rapid development of Arthur 1.2 after the failure of the ARX project. The first release was to be called Arthur 2, but was renamed to RISC OS 2, and was first sold as RISC OS 2.00 in April 1989. The operating system implements co-operative multitasking with some limitations but is not multithreaded. It uses the ADFS filesystem for both floppy and hard disc access. It initially ran from a 512 KiB ROM module. The WIMP interface offers all the standard features and fixes many of the bugs that had hindered Arthur. It lacks virtual memory and extensive memory protection (applications are protected from each other, but many functions have to be implemented as 'modules' which have full access to the memory). At the time of release, the main advantage of the OS was its ROM; it booted very quickly and while it was easy to crash it was impossible to permanently break the OS from software. Its high performance was due to much of the system being written in ARM assembly language. The OS is organised as a relatively small kernel which defines a standard software interface to which extension modules are required to conform. Much of the system's functionality is implemented in modules coded in the ROM, though these can be supplanted by more evolved versions loaded into RAM. Among the kernel facilities are a general mechanism, named the callback handler, which allows a supervisor module to perform process multiplexing. This facility is used by a module forming part of the standard editor program to provide a terminal emulator window for console applications. The same approach made it possible for advanced users to implement modules giving RISC OS the ability to do pre-emptive multitasking. ARX was a Unix-like operating system developed by Acorn Computers Ltd in the UK and at the Acorn Research Centre (ARC) at Palo Alto for their new ARM RISC processors. ... Year 1989 (MCMLXXXIX) was a common year starting on Sunday (link displays 1989 Gregorian calendar). ... It has been suggested that this article or section be merged into Computer_multitasking#Cooperative_multitasking. ... Many programming languages, operating systems, and other software development environments support what are called threads of execution. ... The Advanced Disc Filing System (ADFS) is a computing file system particular to the Acorn computer range and RISC OS based successors. ... A kibibyte (a contraction of kilo binary byte) is a unit of information or computer storage, commonly abbreviated KiB (never kiB). 1 kibibyte = 210 bytes = 1,024 bytes The kibibyte is closely related to the kilobyte, which can be used either as a synonym for kibibyte or to refer to... Read-only memory (usually known by its acronym, ROM) is a class of storage media used in computers and other electronic devices. ... In humanâ€“computer interaction, WIMP stands for window, icon, menu, pointing device, denoting a style of interaction using these elements. ... A computer bug is an error, flaw, mistake, failure, or fault in a computer program that prevents it from working as intended, or produces an incorrect result. ... How virtual memory maps to physical memory Virtual memory is an addressing scheme implemented in hardware and software that allows non-contiguous memory to be addressed as if it were contiguous. ... Memory protection is a system that prevents one process from corrupting the memory of another process running on the same computer at the same time. ... The ARM architecture (previously, the Advanced RISC Machine, and prior to that Acorn RISC Machine) is a 32-bit RISC processor architecture developed by ARM Limited that is widely used in a number of embedded designs. ... See the terminology section, below, regarding inconsistent use of the terms assembly and assembler. ... Random access memory (usually known by its acronym, RAM) is a type of data storage used in computers. ... Apple Terminal. ... Pre-emptive multitasking is a form of multitasking. ...

One unusual and innovative feature of the operating system at the time of its release was its support for high-quality, hinted and anti-aliased outline font rendering, a feature that only became widespread in other operating systems much later.

A slightly updated version RISC OS 2.01 was released later to support the ARM3 processor that was shipped with the Acorn Archimedes A540, Acorn R225/R260 and Acorn A3000. This article or section does not cite its references or sources. ...

RISC OS 3

RISC OS 3.00 was released with the A5000 in 1991; it is almost four times the size of RISC OS 2 and runs from a 2 MiB ROM. It improves multitasking and also places some of the more popular base applications in the ROM. Download high resolution version (1112x834, 126 KB) This image has been released into the public domain by the copyright holder, its copyright has expired, or it is ineligible for copyright. ... Download high resolution version (1112x834, 126 KB) This image has been released into the public domain by the copyright holder, its copyright has expired, or it is ineligible for copyright. ... Year 1991 (MCMXCI) was a common year starting on Tuesday (link will display the 1991 Gregorian calendar). ... The three-letter acronym MIB may refer to any of several concepts: Management information base, a computing information repository used (for example) by SNMP In marbles, any marble, but esp. ...

RISC OS 3.1 was released later and sold built-in to the A3010, A3020, A4000, A4 and later A5000 models. It was also made available as replacement ROMs for the A5000 and earlier Archimedes machines (this is the last RISC OS version suitable for those machines). Three variants were released - RISC OS 3.10 the base version, RISC OS 3.11 which included a slight update that fixes some serial port issues and RISC OS 3.19 which was a German translation. This article or section does not cite its references or sources. ...

RISC OS 3.50 was sold from 1994 with the first Risc PCs. Due to the very different hardware architecture of the Risc PC, including an ARM 6 processor, 16 and 24bit colour and a different IO chip (IOMD), RISC OS 3.50 was not made available for the older Archimedes and A Series ARM 2 and 3 machines. The Risc PC (codenamed Medusa) was Acorn Computers Ltds next generation RISC OS/Acorn RISC Machine computer, launched in 1994, which superseded the Acorn Archimedes. ... The Risc PC (codenamed Medusa) was Acorn Computers Ltds next generation RISC OS/Acorn RISC Machine computer, launched in 1994, which superseded the Acorn Archimedes. ... This article or section does not cite its references or sources. ...

RISC OS 3.60 followed in 1995. The OS features much better hard disk access and its networking was enhanced to include TCP/IP as standard in addition to Acorn's existing proprietary Econet system. The hardware support was also improved; Risc PCs could now use ARM 7 processors. Acorn's A7000 machine with its ARM 7500 processor was also supported. Year 1995 (MCMXCV) was a common year starting on Sunday (link will display full 1995 Gregorian calendar). ... Typical hard drives of the mid-1990s. ... SHASHI KANT SHARMA For the scientific and engineering discipline studying computer networks, see Computer networking. ... The Internet protocol suite is the set of communications protocols that implement the protocol stack on which the Internet runs. ... Econet is an abbreviation of Economy Network. ... The Risc PC (codenamed Medusa) was Acorn Computers Ltds next generation RISC OS/Acorn RISC Machine computer, launched in 1994, which superseded the Acorn Archimedes. ...

RISC OS 3.70 was released in 1996. The primary changes in the OS was support for the StrongARM processor that was made available as an upgrade for the Risc PC. This required extensive code changes due to StrongARM's split data and instruction cache (Harvard architecture). Year 1996 (MCMXCVI) was a leap year starting on Monday (link will display full 1996 Gregorian calendar). ... DEC StrongARM SA-110 Microprocessor The StrongARM microprocessor is a faster version of the Advanced RISC Machines ARM design. ... The Risc PC (codenamed Medusa) was Acorn Computers Ltds next generation RISC OS/Acorn RISC Machine computer, launched in 1994, which superseded the Acorn Archimedes. ... DEC StrongARM SA-110 Microprocessor The StrongARM microprocessor is a faster version of the Advanced RISC Machines ARM design. ... The term Harvard architecture originally referred to computer architectures that used physically separate storage and signal pathways for their instructions and data (in contrast to the von Neumann architecture). ...

RISC OS 3.71 is a small update released to support the hardware in the Acorn A7000+ with its ARM 7500FE processor. The FE offered hardware support for floating point mathematics, which until then was usually emulated in one of the RISC OS Software modules).

Demise of Acorn Computers Ltd

Acorn halted work in all areas except set-top boxes in late 1998 and the company was renamed Element 14 (the 14th element of the periodic table being silicon). RISC OS development was halted during the development of OS 4.0 for the RISC PC II ("Phoebe"), whose completion was also cancelled. A beta version, OS 3.8 for the original RISC PC, had previously been released to developers. The term set-top box (STB) describes a device that connects to a television and some external source of signal, and turns the signal into content then displayed on the screen. ... The periodic table of the chemical elements is a tabular method of displaying the chemical elements, first devised by English analytical chemist John Newlands in 1863. ... It has been suggested that Silicons ranking be merged into this article or section. ...

This led to a number of rescue efforts, including the creation of the ROX Desktop to provide a RISC OS-like interface on Unix and Linux systems. Two similar projects, Impulse and Eidos's Phoenix, have both stalled. A screenshot of the ROX desktop. ... Filiation of Unix and Unix-like systems Unix (officially trademarked as UNIXÂ®) is a computer operating system originally developed in the 1960s and 1970s by a group of AT&T employees at Bell Labs including Ken Thompson, Dennis Ritchie and Douglas McIlroy. ... Linux (IPA pronunciation: ) is a Unix-like computer operating system. ...

RISC OS 4

In 1999 a new company called RISCOS Ltd was founded. They licensed the rights to RISC OS from Element 14 (and eventually from the new owner, Pace Micro) and continued the development of OS 3.8, releasing it as RISC OS 4 in July 1999. According to the company, over 6,400 copies of RISC OS 4.02 were sold up until production was ceased in mid 2005. RISCOS Ltd was a UK limited company created in 1999 to continue user-focused development of the RISC OS operating system after the collapse of Acorn. ... Pace Micro Technology is a British manufacture of set top boxes for digital and analogue satellite television, founded in 1982. ...

In 2002 the company launched RISC OS Select, a subscription scheme allowing users access to the latest OS updates in between major releases. These upgrades are released as soft-loadable patches, separate to the Flash ROM where the main OS is stored, and are loaded at boot time. The scheme was devised to accelerate RISCOS Limited's development cycle by producing extra income in between major releases. It has also allowed the company to subsidise the retail price of ROM releases, which are generally a culmination of the last few Select upgrades with a few extra minor changes.

In April 2004, RISCOS Ltd released the ROM based version 4.39, being dubbed RISC OS Adjust. RISCOS Ltd sold its 500th Adjust ROM in early 2006.

In 2004, RISCOS Ltd privately began work on a 32-bit version of RISC OS Adjust (Adjust 32), which is compatible with current ARM processors and designed for both embedded and desktop forms. The first machine to make use of the updated OS is the Advantage6 A9home (Photo of Portable Desktop Version). It was released in May 2006 after a 12 month Beta testing process, although the current build of Adjust 32, namely RISC OS 4.42, is not yet feature complete. Both 26- and 32-bit builds of new RISC OS 4 releases can now be compiled from the same source code, but will have to be modified to run on each individual machine supported, as the OS has no HAL at present. Instead it has a hardware-abstracted kernel, which allows specific code to be substituted for each platform supported. The A9Home is a small form factor computer running RISC OS. It was officially unveiled at the 2005 Wakefield Show, and is only the second native RISC OS computer to run a 32bit version of RISC OS. It is significantly smaller than even the Mac Mini and housed in cobalt... Source code (commonly just source or code) is any series of statements written in some human-readable computer programming language. ... A hardware abstraction layer (HAL) is an abstraction layer, implemented in software, between the physical hardware of a computer and the software that runs on that computer. ...

RISC OS 4 is also available as an emulator for Windows systems. The emulator is called Virtual Acorn and is sold by 3QD Developments. The latest version is Virtual RPC-Adjust: RO 4.39. Work on an Apple Mac version is ongoing.

RISC OS 5

RISC OS 5 is a separate evolution by Castle Technology Ltd based upon work done by Pace for their NCOS based set top boxes. RISC OS 5 was written to support Castle's Iyonix PC Acorn-compatible, which runs on the Intel XScale ARM processor. Although a wealth of software has now been updated, a few older applications can only be run on RISC OS 5 via an emulator called aemulor, since a minor 26-bit ARM CPU function was removed by Intel from the XScale. Likewise, RISC OS 5 itself had to be ported to run properly on the new CPU, and abstraction of the graphics and other hardware interfaces created, to allow it, for example, to use standard graphics cards, instead of Acorn's own VIDC chip. Castle Technology Ltd. ... The Iyonix PC is an Acorn-clone personal computer from Castle Technology. ... The XScale, a microprocessor core, is Intels implementation of the 5th generation of the ARM architecture, and consists of several distinct families: IXP, IXC, IOP and PXA (see more below). ... In ARM processor architecture, 26-bit refers to the design used in the original ARM processors, where the Program Counter(PC) and Processor Status Register(PSR) were combined into one 32-bit register (R15), the Status flags filling the high 6 bits and the Program Counter taking up the lower...

In July 2003, Castle Technology Ltd bought the head licence for RISC OS from Pace Micro.^[2] RISCOS Ltd and Castle continued maintaining separate development branches of the RISC OS operating system for some time, but as a result of a lengthy dispute over licensing during 2004 the two companies agreed to merge the two competing streams. Whether a unified version will be released is yet to be seen, however, as RISCOS Ltd have continued development of their stream of the OS in preparation to launch Version 6.

Shared Source Initiative

In October 2006, Castle Technology Ltd announced a plan to release elements of RISC OS 5 under a unique source sharing license. The Shared Source Initiative (SSI) is a joint venture between Castle and RISC OS Open Limited (ROOL), a newly formed software development company, which aims to accelerate development and encourage uptake of the OS. Under the custom dual license, released source will be freely available and may be modified and redistributed without royalty for non-commercial use, while commercial usage will incur a per-unit license fee to Castle. The full license has not yet been released. Castle Technology Ltd. ...

The SSI will initially make phased releases of the OS, starting with the following components:

In a Drobe forum, ROOL director Andrew Hodgkinson said the SSI would release as many components as possible, but it was too early to say how much of the OS that might be.

He said: "The ultimate goal would be to have a complete OS there - perhaps, for example, you could build yourself an Iyonix ROM. But that's putting the cart before the horse. We cannot promise being able to reach such a position at this stage, so we're not doing so."

ROOL will maintain the shared source tree and build an international developer community on a non-profit basis to support and encourage development. Both ROOL and Castle intend to provide RISC OS consultancy to clients requiring embedded ARM solutions, already a major market for the OS.

At this stage it is unclear whether RISC OS Ltd, developer of RISC OS 4, will co-operate with the SSI.

The company said on their website: "We await the full details of the licensing terms and conditions that will be applicable to RISC OS 5 source code. When these are known we shall be able to review the situation. However the current expectation is that there are very few features that are present in RISC OS 5 that are missing in RISC OS 6, that have a very high priority for inclusion in future releases of RISC OS 6."

ROL managing director Paul Middleton told Drobe News that the company would not be open sourcing its OS code in the same way.

He said: "It is probably worth pointing out that the 'open sourcing' of RISC OS is going to solely cover RISC OS 5 versions. We do not intend to 'open source' RISC OS 4 versions as some people seem to have assumed.

"I would point out though that we have always been happy to work with developers who require source level access to RISC OS, in the same way that Acorn made sources available for particular projects. The difference between us and ROOL is that we do require any changes made to be fed back to us, as we only want one version of RISC OS 4 to be available."

RISC OS 6

Shortly after Castle announced the SSI, ROL announced RISC OS 6, the next generation of their stream of the operating system. Significant portability, stability and internal structure improvements, including full 26/32 bit neutrality, have laid the foundations for the company's future releases, all of which will be based on Version 6.

RISC OS 6 is now highly modularised, with legacy and hardware specific features abstracted, and other code separated for easier future maintenance and development. Teletext support, device interrupt handler, software-based graphics operations, the real-time clock, the mouse pointer, CMOS RAM support, and hardware timer support have been abstracted out of the kernel and into their own separate modules. Legacy components, like the VIDC driver, and obsolete functionality for the BBC Micro have been abstracted too. AIF and transient utility executable checking has been introduced also to protect against rogue software, while graphics acceleration modules are provided for the SM501 graphics chip in the A9home and for ViewFinder AGP podule cards. The BBC Microcomputer System was a series of microcomputers and associated peripherals designed and built by Acorn Computers Ltd for the BBC Computer Literacy Project operated by the British Broadcasting Corporation. ...

A beta-version of RISC OS 6, Preview 1, is available for free download by subscribers to the Select scheme, both present and those whose subscription was renewed after 30th May 2004 - the last time the company delivered a Select release - but has since lapsed.

Select Edition 4 will be the first product to be based on RISC OS 6. Originally slated for release around mid-2005, it has been subject to lengthy delays due to the company's commitment to porting Adjust 32 to the A9home, which is taking much longer than expected. Many Select subscribers have signaled their anger with RISCOS Ltd, alleging that customers' subscription fees were inappropriately used to fund the A9home port while they had received nothing for over two years.

Select 4 will include new user functionality. As yet RISCOS Ltd have not announced any release dates for RISC OS 6 products, and have refused to speculate on any development progress.

Preview 1 and Select 4 will initially be compatible with only Acorn Risc PC and A7000 machines. RiscStation R7500, MicroDigital Omega and Mico computers will not officially be supported, as the company does not have test machines available and requires proprietary software code to which they don't have the rights. Subsequent versions of Select 4 will also be compatible with the A9home.

An Iyonix-compatible version of RISC OS 6 is described as a possibility - From the RISC OS 6 FAQ : "Some people have assumed that because we have not made any definite announcements with respect to Select 4 on the Iyonix, that we are not interested in doing the work. The facts are however that our resources are limited, and priority has been given to working with partners who actively want RISC OS Select features on their products."

References

Contents

Features

Bundled applications

Early years

RISC OS 2

RISC OS 3

Demise of Acorn Computers Ltd

RISC OS 4

RISC OS 5

Shared Source Initiative

RISC OS 6

References

See also

External links

Contents

Features GA_googleFillSlot("encyclopedia_square");

Bundled applications

Early years

RISC OS 2

RISC OS 3

Demise of Acorn Computers Ltd

RISC OS 4

RISC OS 5

Shared Source Initiative

RISC OS 6

References

See also

External links

Features