Intel fires warning shots at Microsoft, says x86 emulation is a patent minefield
Years ago, I spoke with an attorney with a CS background.  He had once worked on a case like this.  Sharp guy.  He didn't tell me the parties involved, and I didn't ask, though I assume he wouldn't speak openly about it while it was ongoing.  I therefore don't know how it turned out.  It was many years ago, so I might be remembering wrong.  I'm not a lawyer, this is not legal advice (neither mine nor his).<p>Basically, there are two approaches the plaintiff might take here.  The simplest is to cite the doctrine of equivalents[1].  This is basically the notion that if you do the same thing in the same way for the same purpose, then it's the same process, even though you are using digital instructions instead of logic gates.  The legal theory here is pretty well settled.  The problem is that you'd need to justify that digital instructions are obviously equivalent to logic gates, and a skilled professional would have equated them at the time of the patent's filing.<p>The other approach is to argue that an emulator actually is a processor, and therefore fits the literal claims of the patent.  The explanation for this is pretty well-established:  it's literally the Church-Turing Thesis[2].  However, the viability of this argument depends on the language of the patent claims.  Also, it's hard enough to explain the C-T Thesis to CS students.  My undergrad had an entire 1-credit-equivalent course that basically just covered this and the decidability problem.  Explaining it to a judge, who (while likely highly intelligent) probably has no CS background, over the course of litigation is likely to be <i>really</i> hard.<p>Now, Intel certainly has enough resources to do both of these things (and they may also have precedent to cite, that didn't exist back then or that wasn't relevant to that case).  Don't take this as an opinion on any possible result, it's just information such as I remember it.<p>[1]- <a href="https://en.wikipedia.org/wiki/Doctrine_of_equivalents" rel="nofollow">https://en.wikipedia.org/wiki/Doctrine_of_equivalents</a>
[2]- <a href="https://en.wikipedia.org/wiki/Church%E2%80%93Turing_thesis" rel="nofollow">https://en.wikipedia.org/wiki/Church%E2%80%93Turing_thesis</a>