DragonFly is an operating system and environment originally based on FreeBSD. DragonFly branched from FreeBSD in 2003 in order to develop a radically different approach to concurrency, SMP, and most other kernel subsystems.

DragonFly belongs to the same class of operating system as BSD and Linux and is based on the same UNIX ideals and APIs. DragonFly gives the BSD base an opportunity to grow in an entirely different direction from the one taken in the FreeBSD-5 series.

It is our belief that the correct choice of features and algorithms can yield the potential for excellent scalability, robustness, and debuggability in a number of broad system categories. Not just for SMP or NUMA, but for everything from a single-node UP system to a massively clustered system. We believe that a fairly simple but wide-ranging set of goals will lay the groundwork for future growth. The existing BSD cores, including FreeBSD-5, are still primarily based on models which could at best be called 'strained' as applied to modern systems. True innovation has given way to basically just laying on hacks to add features, such as encrypted disks and security layering that in a better environment could be developed at far less cost and with far greater flexibility.

We also believe that it is important to provide API solutions which allow reasonable backwards and forwards version compatibility, at least between userland and the kernel, in a mix-and-match environment. If one considers the situation from the ultimate in clustering... secure anonymous system clustering over the internet, the necessity of having properly specified APIs becomes apparent.

Finally, we believe that a fully integrated and feature-full upgrade mechanism should exist to allow end users and system operators of all walks of life to easily maintain their systems. In this regard, DragonFly has chosen to adopt the BSD PkgSrc system.

DragonFly's ultimate goal is to provide fully cache coherent and fully transparent single-system-image style clustering. Achieving this goal has required a great deal of groundwork to be laid down, with more on its way, in order to properly support the models and functionality required. As of 2006 we are well past the half way mark to our goal!