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Tivoization is the creation of a system that incorporates software under the terms of a copyleft software license (like the GPL), but uses hardware restrictions to prevent users from running modified versions of the software on that hardware. Richard Stallman coined the term in reference to TiVo's use of GNU GPL licensed software on the TiVo brand digital video recorders (DVR), which actively blocks users from running modified software on its hardware by design.〔https://www.gnu.org/licenses/gpl-faq.html#Tivoization GNU.org Frequently Asked Questions about the GNU Licenses〕〔https://www.gnu.org/licenses/quick-guide-gplv3.html A Quick Guide to GPLv3〕 Stallman believes this practice denies users some of the freedom that the GNU General Public License (GNU GPL) was designed to protect.〔(【引用サイトリンク】title=() GPLv3 Update #2 )〕 The Free Software Foundation refers to tivoized hardware as "tyrant devices". ==Overview== TiVo's software incorporates the Linux kernel and GNU software, both of which are licensed under version 2 of the GNU General Public License (GPLv2). GPLv2 requires distributors to make the corresponding source code available to each person who receives the software. The goal of this requirement is to allow users of GPL-covered software to modify the software to better suit their purposes.〔(【引用サイトリンク】title=The Free Software Definition )〕 However, Stallman asserts that TiVo circumvented this goal by making their products run programs only if the program's digital signature matches those authorized by the manufacturer of the TiVo.〔(【引用サイトリンク】title=Using large disks with TiVo )〕 So while TiVo has complied with the GPL v2 requirement to release the source code for others to modify, any modified software will not run on TiVo's hardware. Linus Torvalds, the original author of the Linux kernel, has said that he personally doesn't like DRM, but on the other hand, argued that it is appropriate for TiVo to decide if they will use digital signatures to limit what software may run on the systems that they sell. Torvalds has stated that he believes the use of private digital signatures on software is a beneficial security tool. Torvalds also believes that software licenses should attempt to control only software, not the hardware on which it runs. So, as long as one has access to the software, and can modify it to run on some other hardware, Torvalds believes there is nothing unethical about using digital signatures to prevent running modified copies of Linux.〔(【引用サイトリンク】title=fa.linux.kernel: Linus Torvalds: Flame Linus to a crisp! on 2003-04-24 )〕 Other Linux developers, including Alan Cox, have expressed divergent opinions.〔(【引用サイトリンク】title=Latest Topics )〕 Stallman and the Free Software Foundation have attempted to respond to some of these concerns. They have stated that their goal is for GPLv3 to allow private digital signatures for security purposes, but to still prevent Tivoization. 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「Tivoization」の詳細全文を読む スポンサード リンク
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