Gazelle was a research web browser project by Microsoft Research, first announced in early 2009.[1] The central notion of the project was to apply operating system (OS) principles to browser construction.[2] In particular, the browser had a secure kernel, modeled after an OS kernel, and various web sources run as separate "principals" above that, similar to user space processes in an OS.[2] The goal of doing this was to prevent bad code from one web source to affect the rendering or processing of code from other web sources.[2] Browser plugins are also managed as principals.[2]
Gazelle had a predecessor project, MashupOS, but with Gazelle the emphasis was on a more secure browser.[3][4]
By the July 2009 announcement of ChromeOS, Gazelle was seen as a possible alternative Microsoft architectural approach compared to Google's direction.[5][6][7] That is, rather than the OS being reduced in role to that of a browser, the browser would be strengthened using OS principles.[5]
The Gazelle project became dormant, and ServiceOS arose as a replacement project also related to browser architectures.[8][9] But by 2015, the SecureOS project was also dormant, after Microsoft decided that its new flagship browser would be Edge.[10][11]