reactosfanboy writes "DRM Hacker Alex Ionescu explained the internals of ReactOS in a recent talk. Ionescu indicates that ReactOS is nearly 100% binary and API compatible with the Windows 2003 kernel, and that they are aiming for full Vista compatibility. Ionescu attempted to demonstrate ReactOS but only succeeded in installing it after two BSoDs. This alone should make it clear that ReactOS is still not ready for prime time." In what may be a red flag for Microsoft's lawyers, ReactOS is described as "an environment identical to Windows, both visually and internally." Here are slides from Ionescu's talk (PDF), which might prove more useful than the video offered in various forms at over 450 MB.