Tuesday, February 14, 2012

Tivoization

Tivoization (pronounced "Teevo-ization") is a appellation coined to call the conception of a arrangement that incorporates software beneath the agreement of a copyleft software authorization (like the GPL), but uses accouterments restrictions to anticipate users from active adapted versions of the software on that hardware. Richard Stallman coined the appellation and believes this convenance denies users some of the abandon that the GNU General Public Authorization (GNU GPL) was advised to protect.1 The appellation came about in advertence to TiVo's use of GNU GPL accountant software on the TiVo cast agenda video recorders (DVR) which actively blocks users from active adapted software on its accouterments by design.23

Overview

TiVo's software incorporates the Linux atom and GNU software, both of which are accountant beneath adaptation 2 of the GNU General Public License (GPLv2). GPLv2 requires distributors to accomplish the agnate antecedent cipher accessible to anniversary being who receives the software. The ambition of this claim is to acquiesce users of GPL'd software to adapt the software to bigger clothing their purposes.4

However, Stallman believes TiVo baffled this ambition by authoritative their articles run programs alone if the program's agenda signature matches those accustomed by the architect of the TiVo.5 So while TiVo has complied with the GPL v2 claim to absolution the antecedent cipher for others to modify, any adapted software will not run on TiVo's hardware.

On the added hand, Linus Torvalds, the aboriginal columnist of the Linux kernel, has argued that it is adapted for TiVo to use agenda signatures to absolute what software may run on the systems that they sell. Torvalds has declared that he believes the use of clandestine agenda signatures on software is a benign aegis tool. Torvalds aswell believes that software licenses should attack to ascendancy alone software, not the accouterments on which it runs. So, as continued as one has admission to the software, and can adapt it to run on some added hardware, Torvalds believes there is annihilation bent about application agenda signatures to anticipate active adapted copies of Linux.6 Added Linux developers, including Alan Cox, accept bidding aberrant opinions.7

Stallman and the Free Software Foundation accept attempted to acknowledge to some of these concerns. They accept declared that their ambition is for GPLv3 to acquiesce clandestine agenda signatures for aegis purposes, but to still anticipate Tivoization.

Response

In 2006, Free Software Foundation (FSF) absitively to action TiVo's abstruse arrangement of blocking users from active adapted software. The convenance was tackled by creating a new adaptation of the GNU General Public Authorization (GPL v3) prohibiting this activity.8 The operating arrangement atom included in the TiVo is broadcast beneath the agreement of the GPL, and the FSF's ambition is to ensure that all recipients of software accountant beneath the new GPL are not belted by accouterments constraints on the modification of broadcast software. This new authorization accouterment was accustomed by TiVo in its April 2007 SEC filing: "we may be clumsy to absorb approaching enhancements to the GNU/Linux operating arrangement into our software, which could abnormally affect our business".9 Regardless, the Linux atom has not been afflicted to use GPL v3.

GPLv3

One of the goals of GPL Version 3 is to anticipate "Tivoization". According to Eben Moglen, "the licence should prohibit abstruse agency of artifice of its rules, with the aforementioned accuracy that it prohibits accustomed artifice of its rules."10

Draft 2 of GPLv3 attempted to analyze this.11 However, some Linux atom developers were still anxious that abstract 2 GPLv3 may still prohibit benign uses of agenda signatures.12

In the third and fourth altercation drafts of GPLv3, appear March 28, 2007 and May 31, 2007 respectively, the anti-tivoization article was bound so as not to administer if the software is broadcast to a business.13 Thus, medical accessories and voting machines would not be covered. The final, official GPLv3 was appear on June 29, 2007 with no above changes in account to tivoization about to the fourth draft.

Linus Torvalds said he was "pretty pleased" with the new draft's attitude on DRM.14 However, he still does not abutment relicensing the Linux atom beneath GPLv3:

“ Stallman calls it "tivoization", but that's a chat he has fabricated up, and a appellation I acquisition offensive, so I don't accept to use it. It's abhorrent because Tivo never did annihilation wrong, and the FSF even accustomed that. The actuality that they do their accouterments and accept some DRM issues with the agreeable producers and appropriately wish to assure the candor of that hardware.

The atom authorization covers the *kernel*. It does not awning cossack loaders and hardware, and as far as I'm concerned, humans who accomplish their own accouterments can architecture them any which way they want. Whether that agency "booting alone a specific kernel" or "sharks with lasers", I don't care.

sharks

In any case, alteration the authorization of the Linux atom would acceptable be absurd due to its actual ample amount of absorb holders. Unlike a lot of GPL software, the atom is accountant alone beneath GPLv2 after the diction "or, at your option, any after version", accordingly the acceding of all absorb holders would be appropriate to relicense beneath a new version.16

Some added projects broadly acclimated in Tivoized anchored systems, such as Busybox, accept aswell beneath to move to GPLv3.17