OpenSolaris is an open source version of the Solaris operating system developed by Sun Microsystems. It is based on Solaris and uses the Solaris kernel and many core components. The OpenSolaris project aims to develop Solaris further with an open development process and release components as open source. Some key features of OpenSolaris include the ZFS file system, DTrace dynamic tracing tool, virtualization using containers, logical domains and VirtualBox.