![Image](http://c.fsdn.com/fm/screenshots/8873_thumb.png)
ReactOS is an advanced operating system providing a ground-up implementation of a Microsoft Windows XP compatible operating system. It aims to achieve complete binary compatibility with both applications and device drivers meant for NT and XP operating systems by using a similar architecture and providing a complete and equivalent public interface.
License: GNU General Public License (GPL)
Changes:
Various bugfixes and enhancements to kernel core services (e.g. registry, system information routines, sync primitives like guarded mutex, I/O support, and others). An initiative has been started to fix the remaining unstable parts of the kernel: Memory Manager, caching code, and filesystem driver APIs and other dependencies of Mm. Introduction of a new Portable Structured Exception Handling mechanism (PSEH 2.0). Various GDI drawing problems were fixed.
More...