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The Linux kernel is a Unix-like computer operating system kernel. It is used world-wide: the Linux operating system is based on it and deployed on both traditional computer systems such as personal computers and servers, usually in the form of Linux distributions,〔(【引用サイトリンク】publisher=git.kernel.org )〕 and on various embedded devices such as routers and NAS appliances. The Android operating system for tablet computers, smartphones and smartwatches is also based atop the Linux kernel. The Linux kernel was initially conceived and created in 1991 by Finnish computer science student Linus Torvalds, for his personal computer and with no cross-platform intentions, but has since expanded to support a huge array of computer architectures, many more than other operating systems or kernels. Linux rapidly attracted developers and users who adapted code from other free software projects for use with the new operating system. The Linux kernel has received contributions from nearly 12,000 programmers from more than 1,200 companies, including some of the largest software and hardware vendors. The Linux kernel API, the application programming interface (API) through which user programs interact with the kernel, is meant to be very stable and to not break userspace programs (some programs, such as those with GUIs, rely on other APIs as well). As part of the kernel's functionality, device drivers control the hardware; "mainlined" device drivers are also meant to be very stable. However, the interface between the kernel and loadable kernel modules (LKMs), unlike in many other kernels and operating systems, is not meant to be very stable by design. The Linux kernel, developed by contributors worldwide, is a prominent example of free and open source software. Day-to-day development discussions take place on the Linux kernel mailing list (LKML). The Linux kernel is released under the GNU General Public License version 2 (GPLv2),〔(【引用サイトリンク】url=http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blob;f=COPYING )〕 with some firmware images released under various non-free licenses.〔 ==History== In April 1991, Linus Torvalds, a 21-year-old student at the University of Helsinki, Finland started working on some simple ideas for an operating system. He started with a task switcher in Intel 80386 assembly language and a terminal driver. On 25 August 1991, Torvalds posted the following to ''comp.os.minix'', a newsgroup on Usenet: After that, many people contributed code to the project. Early on, the MINIX community contributed code and ideas to the Linux kernel. At the time, the GNU Project had created many of the components required for a free operating system, but its own kernel, GNU Hurd, was incomplete and unavailable. The BSD operating system had not yet freed itself from legal encumbrances. Despite the limited functionality of the early versions, Linux rapidly accumulated developers and users. By September 1991, version 0.01 of the Linux kernel was released on the FTP server (ftp.funet.fi) of the Finnish University and Research Network (FUNET). It had 10,239 lines of code. In October 1991, version 0.02 of the Linux kernel was released. In December 1991, Linux kernel 0.11 was released. This version was the first to be self-hosted as Linux kernel 0.11 could be compiled by a computer running the same kernel version. When Torvalds released version 0.12 in February 1992, he adopted the GNU General Public License (GPL) over his previous self-drafted license, which had not permitted commercial redistribution. A newsgroup known as ''alt.os.linux'' was started, and on 19 January 1992, the first post to alt.os.linux was made. On 31 March 1992, alt.os.linux became ''comp.os.linux''. The X Window System was soon ported to Linux. In March 1992, Linux version 0.95 was the first to be capable of running X. This large version number jump (from 0.1x to 0.9x) was due to a feeling that a version 1.0 with no major missing pieces was imminent. However, this proved to be somewhat overoptimistic, and from 1993 to early 1994, 15 development versions of version 0.99 appeared. On 14 March 1994, Linux kernel 1.0.0 was released, with 176,250 lines of code. In March 1995, Linux kernel 1.2.0 was released, with 310,950 lines of code. Version 2 of the Linux kernel, released on 9 June 1996, was followed by additional major versions under the version 2 header: * 25 January 1999 release of Linux kernel 2.2.0 (1,800,847 lines of code) * 18 December 1999 – IBM mainframe patches for 2.2.13 were published, allowing Linux kernel to be used on enterprise-class machines * 4 January 2001 release of Linux kernel 2.4.0 (3,377,902 lines of code) * 17 December 2003 release of Linux kernel 2.6.0 (5,929,913 lines of code) Starting in 2004, the release process changed and new kernels started coming out on a regular schedule every 2–3 months, numbered 2.6.0, 2.6.1, up through 2.6.39. On 21 July 2011, Torvalds announced the release of Linux kernel 3.0: "Gone are the 2.6. Version 3.10 of the Linux kernel, released in June 2013, contains 15,803,499 lines of code, while the version 4.1, released in June 2015, has grown to over 19.5 million lines of code contributed by almost 14,000 programmers. 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「Linux kernel」の詳細全文を読む スポンサード リンク
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