Haiku is a free and open source operating system that is compatible with BeOS. It began development in 2001 as the OpenBeOS project after Be Inc. discontinued BeOS development. The first alpha version was released in 2009. Haiku aims to maintain compatibility with BeOS to allow existing BeOS software to run without modifications. Development involves recreating BeOS components like the kernel, file system, and GUI toolkit. While some components are complete, others remain in development stages.