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RISC OS 〔(【引用サイトリンク】title=About us: RISC OS Open Limited FAQ )〕 is a computer operating system originally designed by Acorn Computers Ltd in Cambridge, England. First released in 1987, it was specifically 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 RISC (reduced instruction set computing) architecture supported. Between 1987 and 1998, RISC OS was bundled with every ARM-based Acorn computer model. These included the Acorn Archimedes range, Acorn's R line of computers (with RISC iX as a dual boot option), RiscPC, A7000 and also prototype models such as the Acorn NewsPad and Phoebe computer. A version of the OS (called NCOS) was also used in Oracle's Network Computer and compatible systems. After the break-up of Acorn in 1998, development of the OS was forked and separately continued by several companies, including , Pace Micro Technology and Castle Technology. Since then, it has been bundled with a number of ARM-based desktop computers such as the Iyonix 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, ARMv7 Cortex-A8 processors (such as that used in the BeagleBoard and Touch Book) and Cortex-A9 processors〔 (such as that used in the PandaBoard). There is a development version for the Raspberry Pi. SD card images have been made available free of charge to Raspberry Pi users with a full graphical user interface version and a command-line interface only version (RISC OS Pico).〔(【引用サイトリンク】title=RISC OS Open: Raspberry Pi )〕 == History == (詳細はformat=PDF )〕 Acorn officially halted work on the OS in January 1999, renaming themselves Element 14. In March 1999 a new company called 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, Element 14 sold RISC OS to a company called Pace Micro Technology, 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 (as opposed to 26-bit) variant of RISC OS, known as ''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 source sharing license plan for elements of ''RISC OS 5''. This Shared Source Initiative (SSI) is managed by RISC OS Open Limited. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「RISC OS」の詳細全文を読む スポンサード リンク
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