Favorite quote from the articles so far about BPF: Gregg started with a demonstration tool that he had just written: it's immediate manifestation was in the cr

Favorite quote from the articles so far about BPF: Gregg started with a demonstration tool that he had just written: it's immediate manifestation was in the creation of a high-pitched tone that varied in frequency as he walked around the lectern. It was, it turns out, a BPF-based tool that extracts the signal strength of the laptop's WiFi connection from the kernel and creates a noise in response. As he interfered with that signal with his body, the strength (and thus the pitch of the tone) varied. By tethering the laptop to his phone, he used the tool to measure how close he was to the laptop. It may not be the most practical tool, but it did demonstrate how BPF can be used to do unexpected things.