1 First steps 1.10 Virtual machine configuration When you select a virtual machine from the list in the Manager window, you will see a summary of that machine’s settings on the right. Clicking on the “Settings” button in the toolbar at the top brings up a detailed window where you can configure many of the properties of the selected VM. But be careful: even though it is possible to change all VM settings after installing a guest operating system, certain changes might prevent a guest operating system from functioning correctly if done after installation. Note: The “Settings” button is disabled while a VM is either in the “running” or “saved” state. This is simply because the settings dialog allows you to change fundamental characteristics of the virtual computer that is created for your guest operating system, and this operating system may not take it well when, for example, half of its memory is taken away from under its feet. As a result, if the “Settings” button is disabled, shut down the current VM first. VirtualBox provides a plethora of parameters that can be changed for a virtual machine. The various settings that can be changed in the “Settings” window are described in detail in chapter 3, Configuring virtual machines, page 39. Even more parameters are available with the VirtualBox command line interface see chapter 8, VBoxManage, page 99. 1.11 Removing virtual machines To remove a virtual machine which you no longer need, right-click on it in the Manager’s VM list select “Remove” from the context menu that comes up. A confirmation window will come up that allows you to select whether the machine should only be removed from the list of machines or whether the files associated with it should also be deleted. The “Remove” menu item is disabled while a machine is running. 1.12 Importing and exporting virtual machines VirtualBox can import and export virtual machines in the industry-standard Open Virtualization Format (OVF).5 OVF is a cross-platform standard supported by many virtualization products which allows for creating ready-made virtual machines that can then be imported into a virtualizer such as VirtualBox. VirtualBox makes OVF import and export easy to access and supports it from the Manager window as well as its command-line interface. This allows for packaging so-called virtual appliances: disk images together with configuration settings that can be distributed easily. This way one can offer complete ready-to-use software packages (operating systems with applications) that need no configuration or installation except for importing into VirtualBox. Note: The OVF standard is complex, and support in VirtualBox is an ongoing process. In particular, no guarantee is made that VirtualBox supports all appliances created by other virtualization software. For a list of known limitations, please see chapter 14, Known limitations, page 181. Appliances in OVF format can appear in two variants: 5OVF support was originally introduced with VirtualBox 2.2 and has seen major improvements with every version since. 26