| The ship has sailed on neighbor detection BTW. In the crudest sense of "do I have a neighbour", sure. Of course, that's hardly secret -- if you're in EC2 you can just count your CPUs to figure that out. But there's more questions you can ask: 1. Is my neighbour busy right now? 2. Is my neighbour a busy web server, a busy database, or a busy application server? 3. Is my neighbour hosting Brendan's website? 4. Is my neighbour hosting Brendan's website and he's logged in writing a blog post in vi right now? 5. What's Brendan writing right now? It's not immediately clear which of these questions can be answered using certain capabilities! Few people would have guessed that you could read text off someone's screen using hyperthreading prior to 2005, for example. (Pretty simple although I don't know if anyone has published exploit code for it: Just look at which cache lines are fetched fetching glyphs to render to the screen.) |