1 First steps In particular, Guest Additions provide for “shared folders”, which let you access files from the host system from within a guest machine. Shared folders are described in chapter 4.3, Shared folders, page 62. • Great hardware support. Among others, VirtualBox supports: – Guest multiprocessing (SMP). VirtualBox can present up to 32 virtual CPUs to each virtual machine, irrespective of how many CPU cores are physically present on your host. – USB device support. VirtualBox implements a virtual USB controller and allows you to connect arbitrary USB devices to your virtual machines without having to install device-specific drivers on the host. USB support is not limited to certain device cate- gories. For details, see chapter 3.10.1, USB settings, page 49. – Hardware compatibility. VirtualBox virtualizes a vast array of virtual devices, among them many devices that are typically provided by other virtualization platforms. That includes IDE, SCSI and SATA hard disk controllers, several virtual network cards and sound cards, virtual serial and parallel ports and an Input/Output Advanced Pro- grammable Interrupt Controller (I/O APIC), which is found in many modern PC sys- tems. This eases cloning of PC images from real machines and importing of third-party virtual machines into VirtualBox. – Full ACPI support. The Advanced Configuration and Power Interface (ACPI) is fully supported by VirtualBox. This eases cloning of PC images from real machines or third- party virtual machines into VirtualBox. With its unique ACPI power status support, VirtualBox can even report to ACPI-aware guest operating systems the power status of the host. For mobile systems running on battery, the guest can thus enable energy saving and notify the user of the remaining power (e.g. in fullscreen modes). – Multiscreen resolutions. VirtualBox virtual machines support screen resolutions many times that of a physical screen, allowing them to be spread over a large number of screens attached to the host system. – Built-in iSCSI support. This unique feature allows you to connect a virtual machine directly to an iSCSI storage server without going through the host system. The VM accesses the iSCSI target directly without the extra overhead that is required for virtu- alizing hard disks in container files. For details, see chapter 5.10, iSCSI servers, page 82. – PXE Network boot. The integrated virtual network cards of VirtualBox fully support remote booting via the Preboot Execution Environment (PXE). • Multigeneration branched snapshots. VirtualBox can save arbitrary snapshots of the state of the virtual machine. You can go back in time and revert the virtual machine to any such snapshot and start an alternative VM configuration from there, effectively creating a whole snapshot tree. For details, see chapter 1.9, Snapshots, page 23. You can create and delete snapshots while the virtual machine is running. • Clean architecture unprecedented modularity. VirtualBox has an extremely modular design with well-defined internal programming interfaces and a clean separation of client and server code. This makes it easy to control it from several interfaces at once: for example, you can start a VM simply by clicking on a button in the VirtualBox graphical user interface and then control that machine from the command line, or even remotely. See chapter 1.13, Alternative front-ends, page 28 for details. Due to its modular architecture, VirtualBox can also expose its full functionality and con- figurability through a comprehensive software development kit (SDK), which allows for integrating every aspect of VirtualBox with other software systems. Please see chapter 11, VirtualBox programming interfaces, page 163 for details. 12