Windows Core OS

Windows Core OS (abbreviated as WCOS) is an internal Microsoft effort that aims to provide a universal, modular base for future versions of Microsoft Windows that are not required to be fully compatible with the original desktop variant. It builds on top of the OneCore project, which unified all products previously using forks of the Windows codebase into a single source code repository, enabling everything to be built from a single codebase.

Planning for a common core for all Windows-based products started in 2002, although actual development didn't start until 2014.

List of products based on WCOS

 * Andromeda
 * Xbox One OS
 * FactoryOS
 * Polaris
 * Windows 10X
 * Windows Holographic (for Business)