if you're particularly attuned to tech gossip, you'll know that Google's Chrome OS announcement has prompted a lot of whispers about something called "Gazelle" being cooked up in Microsoft's labs. Part browser, part OS, the word on the street is that Gazelle will be announced soon, and ultimately compete in some way with either Chrome (the browser) or Chrome (the OS). As usual, most of this is just based on hopes and fairytales, but the scholarly folks at Ars Technica have done some digging and come up with a white paper from Microsoft Research that details some of what Gazelle is all about -- and surprise surprise, although it shares some similarities with Chrome, it's actually quite different.
At the most general level, Gazelle is an experiment in building an ultrasecure browser. Like Chrome, it breaks tasks up into different processes, but instead of separating at the page level, Gazelle breaks individual page elements into different processes, allowing content from different servers to be isolated and ultimately providing fine-grained security controls. To manage all these different processes, there's a central "kernel," which is where all the OS talk stems from -- it's all still running on Windows, and the rendering engine is still IE's Trident engine, but Gazelle manages all those separate processes independently, kind of like a virtualized OS. It's certainly interesting stuff, but it's still all just a research project for now -- Chrome OS is still vapor, but it's clear that Google intends to ship something, while Gazelle seems more suited to inspire future versions of IE.