Input devices. Oracle VM VirtualBox can emulate a standard PS/2 keyboard and mouse. These devices are supported by most guest OSes.

In addition, Oracle VM VirtualBox can provide virtual USB input devices to avoid having to capture mouse and keyboard, as described in Section 1.8.2, “Capturing and Releasing Keyboard and Mouse”.

Graphics. The default Oracle VM VirtualBox graphics device for Windows guests is an SVGA device. For Linux guests, the default graphics device emulates a VMware SVGA graphics device. See Section 3.6.1, “Screen Tab”.

For legacy guest OSes, a VGA-compatible graphics device is available.

Storage. Oracle VM VirtualBox emulates the most common types of hard disk controllers. See Section 5.1, “Hard Disk Controllers”. Whereas supporting only one of these controllers would be enough for Oracle VM VirtualBox by itself, this multitude of storage adapters is required for compatibility with other hypervisors. Windows is very selective about its boot devices, and migrating VMs between hypervisors is very difficult or impossible if the storage controllers are different.

Networking. See Section 6.1, “Virtual Networking Hardware”.

USB. Oracle VM VirtualBox emulates these types of USB host controllers: xHCI, EHCI, and OHCI. While xHCI handles all USB transfer speeds, some legacy guest OSes may not support xHCI. Note that for some legacy Windows guests, third party drivers must be installed for xHCI support.

Legacy guest OSes typically support OHCI and EHCI. These two controllers are needed because OHCI only handles USB low-speed and full-speed devices (both USB 1.x and 2.0), while EHCI only handles high-speed devices (USB 2.0 only).

The emulated USB controllers do not communicate directly with devices on the host. Instead they communicate with a virtual USB layer which abstracts the USB protocol and enables the use of remote USB devices.

Audio. See Section 3.8, “Audio Settings”.