What is DragonFly BSD?DragonFly belongs to the same class of operating system as BSD and Linuxand is based on the same UNIX ideals and APIs. DragonFly gives the BSDbase an opportunity to grow in an entirely different direction from the onetaken in the FreeBSD, NetBSD, and OpenBSD series.
From 2003 (when DragonFly first forked from FreeBSD), to early 2007,the DragonFly project focused on rewriting most of the major kernelsubsystems to implement required abstractions and support mechanicsfor the second phase of the project. This involved a great deal of workin nearly every subsystem, particularly the filsystem APIs and kernel core.During all of this we have managed to keep the system updated with regardsto the third party applications and base system utilities needed to makeany system usable in production. We have also adopted the PkgSrc system formanagement of all non-base-system third-party applications in order to poolour resources with other BSD projects using the system.
In the 2007-2008 time-frame a new filesystem called HAMMER was developedfor DragonFly. HAMMER sees its first light of day in the July 20082.0 release. This filesystem has been designed to solve numerous issuesand to add many new capabilities to DragonFly, such as fine-grainedsnapshots, instant crash recovery, and near real-time mirroring.The filesytem is also intended to serve as a basis for the clusteringwork that makes up the second phase of the project.
The second phase of the project is now upon us. The DragonFly project'sultimate goal is to provide native clustering support in the kernel.This involves the creation of a sophisticated cache managementframework for filesystem namespaces, file spaces, and VM spaces, whichallows heavily interactive programs to run across multiple machines withcache coherency fully guaranteed in all respects. This also involves beingable to chop up resources, including the cpu by way of a controlled VMcontext, for safe assignment to unsecured third-party clusters over theinternet (though the security of such clusters itself might be in doubt,the first and most important thing is for systems donating resources to notbe made vulnerable through their donation).
