Anthony does an excellent job of making the arguments in favor of the Linux kernel as a joint work and/or a collective work containing multiple components under separate authorship; but I simply don't agree.
The collective work theory doesn't hold water at all (except with regard to firmware blobs, which indeed are not part of the kernel). The kernel, drivers and all, is a single work of authorship subject to periodic systematic overhaul when internal APIs change. Any piece of the code could get refactored or replicated anywhere else in the kernel at any time without the involvement or approval of its contributor. Nor is anyone else a joint author; Linus doesn't exercise a heavy hand when he doesn't have to; but he alone has the power to approve contributions to the active development branch, and exerts a degree of creative control that no one else can claim. A lot of authority is delegated to maintenance series editors, but that's not where the action is, and they serve at his pleasure and their individual decisions are subject to his veto. You might say that Aalmuhammed was Spike Lee's Alan Cox or David Miller, by analogy with the facts of the case: <quote> [4] Aalmuhammed joined Washington on the movie set. The movie was filmed in the New York metropolitan area and Egypt. Aalmuhammed presented evidence that his involvement in making the movie was very extensive. He reviewed the shooting script for Spike Lee and Denzel Washington and suggested extensive script revisions. Some of his script revisions were included in the released version of the film; others were filmed but not included in the released version. Most of the revisions Aalmuhammed made were to ensure the religious and historical accuracy and authenticity of scenes depicting Malcolm X's religious conversion and pilgrimage to Mecca. [5] Aalmuhammed submitted evidence that he directed Denzel Washington and other actors while on the set, created at least two entire scenes with new characters, translated Arabic into English for subtitles, supplied his own voice for voice-overs, selected the proper prayers and religious practices for the characters, and edited parts of the movie during post production. Washington testified in his deposition that Aalmuhammed's contribution to the movie was "great" because he "helped to rewrite, to make more authentic." Once production ended, Aalmuhammed met with numerous Islamic organizations to persuade them that the movie was an accurate depiction of Malcolm X's life. </quote> But Aalmuhammed still lost the portion of his case that depended on a claim of co-authorship: <quote> [24] Aalmuhammed did not at any time have superintendence of the work. Warner Brothers and Spike Lee controlled it. Aalmuhammed was not the person "who has actually formed the picture by putting the persons in position, and arranging the place. . . ." Spike Lee was, so far as we can tell from the record. Aalmuhammed, like Larson's dramaturg, could make extremely helpful recommendations, but Spike Lee was not bound to accept any of them, and the work would not benefit in the slightest unless Spike Lee chose to accept them. Aalmuhammed lacked control over the work, and absence of control is strong evidence of the absence of co-authorship. ... [27] The Constitution establishes the social policy that our construction of the statutory term "authors" carries out. The Founding Fathers gave Congress the power to give authors copyrights in order "[t]o promote the progress of Science and useful arts." Progress would be retarded rather than promoted, if an author could not consult with others and adopt their useful suggestions without sacrificing sole ownership of the work. Too open a definition of author would compel authors to insulate themselves and maintain ignorance of the contributions others might make. Spike Lee could not consult a scholarly Muslim to make a movie about a religious conversion to Islam, and the arts would be the poorer for that. </quote> Notwithstanding the various degrees of autonomy that driver writers and subsystem maintainers possess, I think that the Linux kernel is neither a joint work nor a collective work, and irrespective of acknowledgments and copyright notices no one other than Linus can claim "authorship" under US law of any portion of the mainstream kernel. Not, that is, unless and until he burns out and hands the reins to a new benevolent dictator. Cheers, - Michael (IANAL, TINLA)