is installed on the host operating system. The host is the physical computer, such as a laptop or server, where you run VirtualBox and the virtual machines you create or import. There are versions of for Windows, macOS, Linux, and Oracle Solaris hosts. See for more information. The VirtualBox Platform Package consists of all open source components and is licensed under the GNU General Public License V3.

The Extension Pack is an optional, separately licensed, installation package that includes these additional features:

• VirtualBox Remote Desktop Protocol (VRDP) server. See Remote Display (VRDP Support). This allows remote clients to connect to a VM using RDP. For example in the case of a server running several applications in different VMs. There is no need for a GUI for any of these on the host machine, but you may wish to connect to them remotely for troubleshooting or maintenance.

• Host webcam passthrough. See Webcam Passthrough.

• Intel PXE boot ROM.

• Disk image encryption with AES algorithm. See Encryption of Disk Images.

• Cloud integration features. See .

The guest operating system (guest OS)is the OS that is running inside a virtual machine. Theoretically, can run any x86 OS such as DOS, Windows, OS/2, FreeBSD, and OpenBSD on an x86_64 host. It can also run a selection of Arm guests on Arm hosts. See .

The virtual machine (VM) is the special environment that creates for your guest OS while it is running. In other words, you run your guest OS in a VM. Normally, a VM is shown as a window on your computer's desktop. Depending on which of the various frontends of you use, the VM might be shown in full screen mode or remotely on another computer.

Internally, treats a VM as a set of parameters that specify its behavior. Some parameters describe hardware settings, such as the amount of memory and number of CPUs assigned. Other parameters describe the state information, such as whether the VM is running or saved.

You can view these VM settings in , in the Settings window, and by running the VBoxManage command. See .

Guest Additions for OSs that qualify for Oracle Premier Support are included in the VirtualBox base package. These are installed inside a VM, once the OS is installed and running, to improve performance of the guest OS and to add extra features. See .