Tivoization
From Wikipedia, the free encyclopedia
Tivoization is the creation of a system that incorporates software under the terms of a copyleft software license, but uses hardware to prevent users from running modified versions of the software on that hardware. Richard Stallman, author of the copyleft GNU General Public License (GPL), coined the term and believes this practice denies users some of the freedom that the GPL was designed to protect.[1]
The term came about in reference to TiVo's use of GPL software on TiVo brand digital video recorders (DVR). TiVo's software incorporates the Linux kernel and parts of GNU, both of which are licensed under the GPL Version 2 (GPL v.2). The GPL v.2 requires TiVo to release the associated source code for others to use and modify. One of the goals of this GPL requirement is to allow others to modify the software to better suit their purposes.[2]
However, Stallman believes TiVo circumvented this goal by making their products run programs only if the program's digital signature matches those authorised by the manufacturer of the TiVo.[3] So while TiVo has complied with the GPL v.2 requirement to release the source code for others to modify, any modified software will not run on TiVo's hardware. As a result, one of the goals of the proposed GPL Version 3 is to prevent "Tivoization"; according to Eben Moglen, "the licence should prohibit technical means of evasion of its rules, with the same clarity that it prohibits legal evasion of its rules."[4]
On the other hand, Linus Torvalds, the author of the Linux kernel, has argued that it is appropriate for TiVo to 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 are a beneficial security tool. Torvalds also believes that software licenses should only attempt to control software, not the hardware on which it runs. So 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.[5] Other Linux developers have expressed divergent opinions, including Alan Cox.[6]
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. Draft 2 of GPLv3 attempted to clarify this.[7] However, many Linux developers were still concerned that draft 2 GPLv3 may still prohibit beneficial uses of digital signatures.[8] A third draft was released on March 28, 2007.[9] This draft restricts the anti-Tivoization clauses to the legal definition of "consumer products". Linus Torvalds has said he is "pretty pleased" with the new draft and its stance on DRM.[10]
[edit] Notes
- ^ http://gplv3.fsf.org/pipermail/info-gplv3/2006-February/000001.html
- ^ http://www.gnu.org/philosophy/free-sw.html
- ^ http://www.gratisoft.us/tivo/bigdisk.html
- ^ http://www.fsfeurope.org/projects/gplv3/barcelona-moglen-transcript.en.html#drm
- ^ http://groups.google.com/group/fa.linux.kernel/browse_frm/thread/2f93510ff38d9089/
- ^ http://news.zdnet.co.uk/software/0,1000000121,39249913,00.htm
- ^ http://gplv3.fsf.org/drm-dd2.html
- ^ http://groups.google.com/group/linux.kernel/msg/36ad030397f575f5
- ^ http://gplv3.fsf.org/gpl-draft-2007-03-28.html
- ^ http://news.com.com/2061-10795_3-6171300.html
[edit] External links
- An Introduction to Tivoization by The Linux Information Project (LINFO)
- Stallman, Torvalds, Moglen share views on DRM and GPLv3 - by Shashank Sharma August 09, 2006, from Newsforge
- TiVo's GPL-required modifications to the Linux kernel, glibc, and other software
- Richard Stallman's explanations of "tivoisation":
- Eben Moglen's explanations:
- Ciaran O'Riordan's explanations:
