Microsoft library OS ‘Drawbridge’ mixes app compatibility with security


Some of our readers may remember Microsoft’s Singularity project, an experimental operating system built by Microsoft as a test case for a secure, microkernel OS written using managed code. While its practical applications are still limited, Microsoft are now developing a new library operating system codenamed “Drawbridge” with the purpose of running Windows applications.

Mary Jo Foley reports that Drawbridge follows similar ideas seen in earlier exokernel OS designs where the primary goal “is to avoid forcing any particular abstraction upon applications, instead allowing them to use or implement whatever abstractions are best suited to their task without having to layer them on top of other abstractions which may impose limits or unnecessary overhead”. Drawbridge may be an early design from Microsoft with the ultimate goal of being able to make substantial changes to the OS kernel without having to sacrifice Windows’ longstanding backwards compatibility of applications…