This is the suplementary kernel driver for the VirtualBox virtualisation environment. To build the package for a kernel different from the running one, start the script setting the KERNEL variable as in KERNEL=2.6.27.16 ./virtualbox-kernel.SlackBuild If you want to build a kernel module for an other virtualbox version you can use the included "virtualbox-kernel-mksrctarball.sh" which will generate the needed source package for you. You will need to have the coresponding virtualbox-ose version already installed.