Linux: Difference between revisions

Revision as of 21:05, 2 August 2009

Revision as of 01:31, 4 August 2009

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The Linux kernel and most GNU software are [[software license|license]]d under the [[GNU General Public License]] (GPL). The GPL requires that anyone who distributes the Linux kernel must make the source code (and any modifications) available to the recipient under the same terms. In 1997, Linus Torvalds stated, “Making Linux GPL'd was definitely the best thing I ever did.”<ref>{{cite web | url = http://kde.sw.com.sg/food/linus.html | title = Linus Torvalds interview | accessdate = 2007-09-13 |archiveurl=http://web.archive.org/web/20070311190841/http://kde.sw.com.sg/food/linus.html |archivedate=2007-03-11}}</ref> Other key components of a Linux system may use other licenses; many libraries use the [[GNU Lesser General Public License]] (LGPL), a more permissive variant of the GPL, and the [[X Window System]] uses the [[MIT License]].

Torvalds has publicly statedstates that he would not move the Linux kernel (currentlywill licensednot undermove GPLfrom version 2) to version 3 of the GPL, releasedto inversion mid-2007,3. He specifically citingdislikes some provisions in the new license which prohibit the use of the software in [[digital rights management]].,<ref>{{cite web | url=http://lkml.org/lkml/2006/1/25/273 | title=Re: GPL V3 and Linux ─ Dead Copyright Holders | author=Torvalds, Linus | date=2006-01-26 | publisher=[[Linux Kernel Mailing List]]}}</ref><ref>{{cite web | url=http://lkml.org/lkml/2006/9/25/161 | title=Re: GPLv3 Position Statement | author=Torvalds, Linus | date=2006-09-25 | publisher=[[Linux Kernel Mailing List]]}}</ref> and it would also be impractical to obtain permission from all the copyright holders, who number in the thousands.<ref>http://www.linux-watch.com/news/NS3301105877.html</ref>

A 2001 study of [[Red Hat Linux]] 7.1 found that this distribution contained 30 million [[source lines of code]]. Using the [[COCOMO|Constructive Cost Model]], the study estimated that this distribution required about eight thousand man-years of development time. According to the study, if all this software had been developed by conventional [[proprietary software|proprietary]] means, it would have cost about ${{formatprice|{{inflation|US|1080000000|2000}}|0}} ({{CURRENTISOYEAR}} US dollars) to develop in the United States.<ref name = "estimating_size">{{cite web | first = David A | last = Wheeler | date = 2002-07-29 | url = http://www.dwheeler.com/sloc/redhat71-v1/redhat71sloc.html | title = More Than a Gigabuck: Estimating GNU/Linux's Size | accessdate = 2006-05-11 }}</ref>