Haiku

Haiku is an open-source operating system, currently in development, that specifically targets personal computing. Inspired by the Be Operating System (BeOS), Haiku aims to become a fast, efficient, simple to use, easy to learn and yet very powerful system for computer users of all levels. The key highlights that distinguish Haiku from other operating systems include: specific focus on personal computing, custom kernel designed for responsiveness, fully threaded design for great efficiency with multi-processor/core CPUs, rich object-oriented API for faster development, database-like file system (BFS) with support for indexed metadata, and unified, cohesive interface.