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<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN"
<chapter id="Introduction">
<title>First steps</title>
<para>Welcome to $VBOX_PRODUCT!</para>
<para>VirtualBox is a cross-platform virtualization application. What does
that mean? For one thing, it installs on your existing Intel or AMD-based
computers, whether they are running Windows, Mac, Linux or Solaris operating
systems. Secondly, it extends the capabilities of your existing computer so
that it can run multiple operating systems (inside multiple virtual
machines) at the same time. So, for example, you can run Windows and Linux
on your Mac, run Windows Server 2008 on your Linux server, run Linux on your
Windows PC, and so on, all alongside your existing applications. You can
install and run as many virtual machines as you like -- the only practical
limits are disk space and memory.</para>
<para>VirtualBox is deceptively simple yet also very powerful. It can run
everywhere from small embedded systems or desktop class machines all the way
up to datacenter deployments and even Cloud environments.</para>
<para>The following screenshot shows you how VirtualBox, installed on a Mac
computer, is running Windows 7 in a virtual machine window:</para>
<para><mediaobject>
<imageobject>
width="14cm" />
</imageobject>
</mediaobject></para>
<para>In this User Manual, we'll begin simply with a quick introduction to
virtualization and how to get your first virtual machine running with the
easy-to-use VirtualBox graphical user interface. Subsequent chapters will go
into much more detail covering more powerful tools and features, but
fortunately, it is not necessary to read the entire User Manual before you
can use VirtualBox.</para>
<para>You can find a summary of VirtualBox's capabilities in <xref
linkend="features-overview" />. For existing VirtualBox users who just want
to see what's new in this release, there is a detailed list in <xref
linkend="ChangeLog" />.</para>
<sect1>
<title>Why is virtualization useful?</title>
<para>The techniques and features that VirtualBox provides are useful for
several scenarios:</para>
<itemizedlist>
<listitem>
<para><emphasis role="bold">Running multiple operating systems
simultaneously.</emphasis> VirtualBox allows you to run more than one
operating system at a time. This way, you can run software written for
one operating system on another (for example, Windows software on
Linux or a Mac) without having to reboot to use it. Since you can
configure what kinds of "virtual" hardware should be presented to each
such operating system, you can install an old operating system such as
DOS or OS/2 even if your real computer's hardware is no longer
supported by that operating system.</para>
</listitem>
<listitem>
<para><emphasis role="bold">Easier software installations.</emphasis>
Software vendors can use virtual machines to ship entire software
configurations. For example, installing a complete mail server
solution on a real machine can be a tedious task. With VirtualBox,
such a complex setup (then often called an "appliance") can be packed
into a virtual machine. Installing and running a mail server becomes
as easy as importing such an appliance into VirtualBox.</para>
</listitem>
<listitem>
<para><emphasis role="bold">Testing and disaster recovery.</emphasis>
Once installed, a virtual machine and its virtual hard disks can be
considered a "container" that can be arbitrarily frozen, woken up,
copied, backed up, and transported between hosts.</para>
<para>On top of that, with the use of another VirtualBox feature
called "snapshots", one can save a particular state of a virtual
machine and revert back to that state, if necessary. This way, one can
freely experiment with a computing environment. If something goes
wrong (e.g. after installing misbehaving software or infecting the
guest with a virus), one can easily switch back to a previous snapshot
and avoid the need of frequent backups and restores.</para>
<para>Any number of snapshots can be created, allowing you to travel
back and forward in virtual machine time. You can delete snapshots
while a VM is running to reclaim disk space.</para>
</listitem>
<listitem>
<para><emphasis role="bold">Infrastructure consolidation.</emphasis>
Virtualization can significantly reduce hardware and electricity
costs. Most of the time, computers today only use a fraction of their
potential power and run with low average system loads. A lot of
hardware resources as well as electricity is thereby wasted. So,
instead of running many such physical computers that are only
partially used, one can pack many virtual machines onto a few powerful
hosts and balance the loads between them.</para>
</listitem>
</itemizedlist>
</sect1>
<sect1 id="virtintro">
<title>Some terminology</title>
<para>When dealing with virtualization (and also for understanding the
following chapters of this documentation), it helps to acquaint oneself
with a bit of crucial terminology, especially the following terms:</para>
<glosslist>
<glossentry>
<glossterm>Host operating system (host OS).</glossterm>
<glossdef>
<para>This is the operating system of the physical computer on which
VirtualBox was installed. There are versions of VirtualBox for
Windows, Mac OS X, Linux and Solaris hosts; for details, please see
<xref linkend="hostossupport" />.</para>
<para>Most of the time, this User Manual discusses all VirtualBox
versions together. There may be platform-specific differences which
we will point out where appropriate.</para>
</glossdef>
</glossentry>
<glossentry>
<glossterm>Guest operating system (guest OS).</glossterm>
<glossdef>
<para>This is the operating system that is running inside the
virtual machine. Theoretically, VirtualBox can run any x86 operating
system (DOS, Windows, OS/2, FreeBSD, OpenBSD), but to achieve
near-native performance of the guest code on your machine, we had to
go through a lot of optimizations that are specific to certain
operating systems. So while your favorite operating system
<emphasis>may</emphasis> run as a guest, we officially support and
optimize for a select few (which, however, include the most common
ones).</para>
<para>See <xref linkend="guestossupport" /> for details.</para>
</glossdef>
</glossentry>
<glossentry>
<glossterm>Virtual machine (VM).</glossterm>
<glossdef>
<para>This is the special environment that VirtualBox creates for
your guest operating system while it is running. In other words, you
run your guest operating system "in" a VM. Normally, a VM will be
shown as a window on your computer's desktop, but depending on which
of the various frontends of VirtualBox you use, it can be displayed
in full screen mode or remotely on another computer.</para>
<para>In a more abstract way, internally, VirtualBox thinks of a VM
as a set of parameters that determine its behavior. They include
hardware settings (how much memory the VM should have, what hard
disks VirtualBox should virtualize through which container files,
what CDs are mounted etc.) as well as state information (whether the
VM is currently running, saved, its snapshots etc.). These settings
are mirrored in the VirtualBox Manager window as well as the
<computeroutput>VBoxManage</computeroutput> command line program;
see <xref linkend="vboxmanage" />. In other words, a VM is also what
you can see in its settings dialog.</para>
</glossdef>
</glossentry>
<glossentry>
<glossterm>Guest Additions.</glossterm>
<glossdef>
<para>This refers to special software packages which are shipped
with VirtualBox but designed to be installed
<emphasis>inside</emphasis> a VM to improve performance of the guest
OS and to add extra features. This is described in detail in <xref
linkend="guestadditions" />.</para>
</glossdef>
</glossentry>
</glosslist>
</sect1>
<sect1 id="features-overview">
<title>Features overview</title>
<para>Here's a brief outline of VirtualBox's main features:</para>
<itemizedlist>
<listitem>
<para><emphasis role="bold">Portability.</emphasis> VirtualBox runs on
a large number of 32-bit and 64-bit host operating systems (again, see
<xref linkend="hostossupport" /> for details).</para>
<para>VirtualBox is a so-called "hosted" hypervisor (sometimes
referred to as a "type 2" hypervisor). Whereas a "bare-metal" or "type
1" hypervisor would run directly on the hardware, VirtualBox requires
an existing operating system to be installed. It can thus run
alongside existing applications on that host.</para>
<para>To a very large degree, VirtualBox is functionally identical on
all of the host platforms, and the same file and image formats are
used. This allows you to run virtual machines created on one host on
another host with a different host operating system; for example, you
can create a virtual machine on Windows and then run it under
Linux.</para>
<para>In addition, virtual machines can easily be imported and
exported using the Open Virtualization Format (OVF, see <xref
linkend="ovf" />), an industry standard created for this purpose. You
can even import OVFs that were created with a different virtualization
software.</para>
</listitem>
<listitem>
<para><emphasis role="bold">No hardware virtualization
required.</emphasis> For many scenarios, VirtualBox does not require
the processor features built into newer hardware like Intel VT-x or
AMD-V. As opposed to many other virtualization solutions, you can
therefore use VirtualBox even on older hardware where these features
are not present. The technical details are explained in <xref
linkend="hwvirt" />.</para>
</listitem>
<listitem>
<para><emphasis role="bold">Guest Additions: shared folders, seamless
windows, 3D virtualization.</emphasis> The VirtualBox Guest Additions
are software packages which can be installed
<emphasis>inside</emphasis> of supported guest systems to improve
their performance and to provide additional integration and
communication with the host system. After installing the Guest
Additions, a virtual machine will support automatic adjustment of
video resolutions, seamless windows, accelerated 3D graphics and more.
The Guest Additions are described in detail in <xref
linkend="guestadditions" />.</para>
<para>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 <xref
linkend="sharedfolders" />.</para>
</listitem>
<listitem>
<para><emphasis role="bold">Great hardware support.</emphasis> Among
others, VirtualBox supports:</para>
<itemizedlist>
<listitem>
<para><emphasis role="bold">Guest multiprocessing
(SMP).</emphasis> VirtualBox can present up to 32 virtual CPUs to
each virtual machine, irrespective of how many CPU cores are
physically present on your host.</para>
</listitem>
<listitem>
<para><emphasis role="bold">USB device support.</emphasis>
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 categories. For details, see
<xref linkend="settings-usb" />.</para>
</listitem>
<listitem>
<para><emphasis role="bold">Hardware compatibility.</emphasis>
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
Controller (I/O APIC), which is found in many modern PC systems.
This eases cloning of PC images from real machines and importing
of third-party virtual machines into VirtualBox.</para>
</listitem>
<listitem>
<para><emphasis role="bold">Full ACPI support.</emphasis> 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 <emphasis role="bold">ACPI power status support,</emphasis>
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 full screen modes).</para>
</listitem>
<listitem>
<para><emphasis role="bold">Multiscreen resolutions.</emphasis>
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.</para>
</listitem>
<listitem>
<para><emphasis role="bold">Built-in iSCSI support.</emphasis>
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 virtualizing hard disks in
container files. For details, see <xref
linkend="storage-iscsi" />.</para>
</listitem>
<listitem>
<para><emphasis role="bold">PXE Network boot.</emphasis> The
integrated virtual network cards of VirtualBox fully support
remote booting via the Preboot Execution Environment (PXE).</para>
</listitem>
</itemizedlist>
</listitem>
<listitem>
<para><emphasis role="bold">Multigeneration branched
snapshots.</emphasis> 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 <xref linkend="snapshots" />. You can create and
delete snapshots while the virtual machine is running.</para>
</listitem>
<listitem>
<para><emphasis role="bold">VM groups.</emphasis> VirtualBox provides a
groups feature that enables the user to organize and control virtual machines
collectively, as well as individually. In addition to basic groups, it
is also possible for any VM to be in more than one group, and for
groups to be nested in a hierarchy -- i.e. groups of groups. In
general, the operations that can be performed on groups are the same as
those that can be applied to individual VMs i.e. Start, Pause, Reset,
Close (Save state, Send Shutdown, Poweroff), Discard Saved State, Show
in fileSystem, Sort.</para>
</listitem>
<listitem>
<para><emphasis role="bold">Clean architecture; unprecedented
modularity.</emphasis> 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
<xref linkend="frontends" /> for details.</para>
<para>Due to its modular architecture, VirtualBox can also expose its
full functionality and configurability through a comprehensive
<emphasis role="bold">software development kit (SDK),</emphasis> which
allows for integrating every aspect of VirtualBox with other software
systems. Please see <xref linkend="VirtualBoxAPI" /> for
details.</para>
</listitem>
<listitem>
<para><emphasis role="bold">Remote machine display.</emphasis> The
VirtualBox Remote Desktop Extension (VRDE) allows for high-performance
remote access to any running virtual machine. This extension supports
the Remote Desktop Protocol (RDP) originally built into Microsoft
Windows, with special additions for full client USB support.</para>
<para>The VRDE does not rely on the RDP server that is built into
Microsoft Windows; instead, it is plugged directly into the
virtualization layer. As a result, it works with guest operating
systems other than Windows (even in text mode) and does not require
application support in the virtual machine either. The VRDE is
described in detail in <xref linkend="vrde" />.</para>
<para>On top of this special capacity, VirtualBox offers you more
unique features:<itemizedlist>
<listitem>
<para><emphasis role="bold">Extensible RDP
authentication.</emphasis> VirtualBox already supports Winlogon
on Windows and PAM on Linux for RDP authentication. In addition,
it includes an easy-to-use SDK which allows you to create
arbitrary interfaces for other methods of authentication; see
<xref linkend="vbox-auth" /> for details.</para>
</listitem>
<listitem>
<para><emphasis role="bold">USB over RDP.</emphasis> Via RDP
virtual channel support, VirtualBox also allows you to connect
arbitrary USB devices locally to a virtual machine which is
running remotely on a VirtualBox RDP server; see <xref
linkend="usb-over-rdp" /> for details.</para>
</listitem>
</itemizedlist></para>
</listitem>
</itemizedlist>
</sect1>
<sect1 id="hostossupport">
<title>Supported host operating systems</title>
<para>Currently, VirtualBox runs on the following host operating
systems:</para>
<itemizedlist>
<listitem>
<para><emphasis role="bold">Windows</emphasis> hosts:<itemizedlist>
<listitem>
<para>Windows Vista SP1 and later (32-bit and 64-bit<footnote>
<para>Support for 64-bit Windows was added with VirtualBox
1.5.</para>
</footnote>).</para>
</listitem>
<listitem>
<para>Windows Server 2008 (64-bit)</para>
</listitem>
<listitem>
<para>Windows Server 2008 R2 (64-bit)</para>
</listitem>
<listitem>
<para>Windows 7 (32-bit and 64-bit)</para>
</listitem>
<listitem>
<para>Windows 8 (32-bit and 64-bit)</para>
</listitem>
<listitem>
<para>Windows 8.1 (32-bit and 64-bit)</para>
</listitem>
<listitem>
<para>Windows Server 2012 (64-bit)</para>
</listitem>
<listitem>
<para>Windows Server 2012 R2 (64-bit)</para>
</listitem>
</itemizedlist></para>
</listitem>
<listitem>
<para><emphasis role="bold">Mac OS X</emphasis> hosts:<footnote>
<para>Preliminary Mac OS X support (beta stage) was added with
VirtualBox 1.4, full support with 1.6. Mac OS X 10.4 (Tiger)
support was removed with VirtualBox 3.1. Mac OS X 10.7 (Lion)
and earlier was removed with VirtualBox 5.0.</para>
</footnote></para>
<itemizedlist>
<listitem>
<para>10.8 (Mountain Lion)</para>
</listitem>
<listitem>
<para>10.9 (Mavericks)</para>
</listitem>
<listitem>
<para>10.10 (Yosemite)</para>
</listitem>
</itemizedlist>
<para>Intel hardware is required; please see <xref
linkend="KnownIssues" /> also.</para>
</listitem>
<listitem>
<para><emphasis role="bold">Linux</emphasis> hosts (32-bit and
64-bit<footnote>
<para>Support for 64-bit Linux was added with VirtualBox
1.4.</para>
</footnote>). Among others, this includes:<itemizedlist>
<listitem>
<para>Ubuntu 10.04 to 14.10</para>
</listitem>
<listitem>
</listitem>
<listitem>
<para>Oracle Enterprise Linux 5, Oracle Linux 6</para>
</listitem>
<listitem>
<para>Redhat Enterprise Linux 5 and 6</para>
</listitem>
<listitem>
<para>Fedora Core 6 to 20</para>
</listitem>
<listitem>
<para>Gentoo Linux</para>
</listitem>
<listitem>
<para>openSUSE 11.0, 11.1, 11.2, 11.3, 11.4, 12.1, 12.2, 13.1</para>
</listitem>
<listitem>
<para>Mandriva 2011</para>
</listitem>
</itemizedlist></para>
<para>It should be possible to use VirtualBox on most systems based on
Linux kernel 2.6 or 3.x using either the VirtualBox installer or by doing a
manual installation; see <xref linkend="install-linux-host" />. However,
the formally tested and supported Linux distributions are those for
which we offer a dedicated package.</para>
<para>Note that starting with VirtualBox 2.1, Linux 2.4-based host
operating systems are no longer supported.</para>
</listitem>
<listitem>
<para><emphasis role="bold">Solaris</emphasis> hosts (64-bit only) are
supported with the restrictions listed in <xref
linkend="KnownIssues" />:<itemizedlist>
<listitem>
<para>Solaris 11</para>
</listitem>
<listitem>
<para>Solaris 10 (U10 and higher)</para>
</listitem>
</itemizedlist></para>
</listitem>
</itemizedlist>
<para>Note that the above list is informal. Oracle support for customers
who have a support contract is limited to a subset of the listed host
operating systems. Also, any feature which is marked as <emphasis
role="bold">experimental</emphasis> is not supported. Feedback and
suggestions about such features are welcome.</para>
</sect1>
<sect1 id="intro-installing">
<title>Installing VirtualBox and extension packs</title>
<para>VirtualBox comes in many different packages, and installation
depends on your host operating system. If you have installed software
before, installation should be straightforward: on each host platform,
VirtualBox uses the installation method that is most common and easy to
use. If you run into trouble or have special requirements, please refer to
<xref linkend="installation" /> for details about the various installation
methods.</para>
<para>Starting with version 4.0, VirtualBox is split into several
components.<orderedlist>
<listitem>
<para>The base package consists of all open-source components and is
licensed under the GNU General Public License V2.</para>
</listitem>
<listitem>
<para>Additional extension packs can be downloaded which extend the
functionality of the VirtualBox base package. Currently, Oracle
provides the one extension pack, which can be found at <ulink
and provides the following added functionality:<orderedlist>
<listitem>
<para>The virtual USB 2.0 (EHCI) device; see <xref
linkend="settings-usb" />.</para>
</listitem>
<listitem>
<para>The virtual USB 3.0 (xHCI) device; see <xref
linkend="settings-usb" />.</para>
</listitem>
<listitem>
<para>VirtualBox Remote Desktop Protocol (VRDP) support; see
<xref linkend="vrde" />.</para>
</listitem>
<listitem>
<para>Host webcam passthrough; see chapter <xref
linkend="webcam-passthrough" />.</para>
</listitem>
<listitem>
<para>Intel PXE boot ROM.</para>
</listitem>
<listitem>
<para>Experimental support for PCI passthrough on Linux hosts;
see <xref linkend="pcipassthrough" />.</para>
</listitem>
</orderedlist></para>
<para>VirtualBox extension packages have a
<computeroutput>.vbox-extpack</computeroutput> file name extension.
To install an extension, simply double-click on the package file
and a Network Operations Manager window will appear, guiding you
through the required steps.</para>
<para>To view the extension packs that are currently installed,
please start the VirtualBox Manager (see the next section). From the
"File" menu, please select "Preferences". In the window that shows
up, go to the "Extensions" category which shows you the extensions
which are currently installed and allows you to remove a package or
add a new one.</para>
<para>Alternatively you can use VBoxManage on the command line: see
<xref linkend="vboxmanage-extpack" /> for details.</para>
</listitem>
</orderedlist></para>
</sect1>
<sect1>
<title>Starting VirtualBox</title>
<para>After installation, you can start VirtualBox as
follows:<itemizedlist>
<listitem>
<para>On a Windows host, in the standard "Programs" menu, click on
the item in the "VirtualBox" group. On Vista or Windows 7, you can
also type "VirtualBox" in the search box of the "Start" menu.</para>
</listitem>
<listitem>
<para>On a Mac OS X host, in the Finder, double-click on the
"VirtualBox" item in the "Applications" folder. (You may want to
drag this item onto your Dock.)</para>
</listitem>
<listitem>
<para>On a Linux or Solaris host, depending on your desktop
environment, a "VirtualBox" item may have been placed in either the
"System" or "System Tools" group of your "Applications" menu.
Alternatively, you can type
<computeroutput>VirtualBox</computeroutput> in a terminal.</para>
</listitem>
</itemizedlist></para>
<para>When you start VirtualBox for the first time, a window like the
following should come up:</para>
<para><mediaobject>
<imageobject>
width="10cm" />
</imageobject>
</mediaobject>This window is called the <emphasis
role="bold">"VirtualBox Manager".</emphasis> On the left, you can see a
pane that will later list all your virtual machines. Since you have not
created any, the list is empty. A row of buttons above it allows you to
create new VMs and work on existing VMs, once you have some. The pane on
the right displays the properties of the virtual machine currently
selected, if any. Again, since you don't have any machines yet, the pane
displays a welcome message.</para>
<para>To give you an idea what VirtualBox might look like later, after you
have created many machines, here's another example:</para>
<para><mediaobject>
<imageobject>
width="10cm" />
</imageobject>
</mediaobject></para>
</sect1>
<sect1 id="gui-createvm">
<title>Creating your first virtual machine</title>
<para>Click on the "New" button at the top of the VirtualBox Manager
window. A wizard will pop up to guide you through setting up a new virtual
machine (VM):</para>
<para><mediaobject>
<imageobject>
width="10cm" />
</imageobject>
</mediaobject>On the following pages, the wizard will ask you for the
bare minimum of information that is needed to create a VM, in
particular:<orderedlist>
<listitem>
<para>The <emphasis role="bold">VM name</emphasis> will later be
shown in the VM list of the VirtualBox Manager window, and it will
be used for the VM's files on disk. Even though any name could be
used, keep in mind that once you have created a few VMs, you will
appreciate if you have given your VMs rather informative names; "My
VM" would thus be less useful than "Windows XP SP2 with
OpenOffice".</para>
</listitem>
<listitem>
<para>For <emphasis role="bold">"Operating System Type",</emphasis>
select the operating system that you want to install later. The
supported operating systems are grouped; if you want to install
something very unusual that is not listed, select "Other". Depending
on your selection, VirtualBox will enable or disable certain VM
settings that your guest operating system may require. This is
particularly important for 64-bit guests (see <xref
linkend="intro-64bitguests" />). It is therefore recommended to
always set it to the correct value.</para>
</listitem>
<listitem>
<para>On the next page, select the <emphasis role="bold">memory
(RAM)</emphasis> that VirtualBox should allocate every time the
virtual machine is started. The amount of memory given here will be
taken away from your host machine and presented to the guest
operating system, which will report this size as the (virtual)
computer's installed RAM.</para>
<para><note>
<para>Choose this setting carefully! The memory you give to the
VM will not be available to your host OS while the VM is
running, so do not specify more than you can spare. For example,
if your host machine has 1 GB of RAM and you enter 512 MB as the
amount of RAM for a particular virtual machine, while that VM is
running, you will only have 512 MB left for all the other
software on your host. If you run two VMs at the same time, even
more memory will be allocated for the second VM (which may not
even be able to start if that memory is not available). On the
other hand, you should specify as much as your guest OS (and
your applications) will require to run properly.</para>
</note></para>
<para>A Windows XP guest will require at least a few hundred MB RAM
to run properly, and Windows Vista will even refuse to install with
less than 512 MB. Of course, if you want to run graphics-intensive
applications in your VM, you may require even more RAM.</para>
<para>So, as a rule of thumb, if you have 1 GB of RAM or more in
your host computer, it is usually safe to allocate 512 MB to each
VM. But, in any case, make sure you always have at least 256 to 512
MB of RAM left on your host operating system. Otherwise you may
cause your host OS to excessively swap out memory to your hard disk,
effectively bringing your host system to a standstill.</para>
<para>As with the other settings, you can change this setting later,
after you have created the VM.</para>
</listitem>
<listitem>
<para>Next, you must specify a <emphasis role="bold">virtual hard
disk</emphasis> for your VM.</para>
<para>There are many and potentially complicated ways in which
VirtualBox can provide hard disk space to a VM (see <xref
linkend="storage" /> for details), but the most common way is to use
a large image file on your "real" hard disk, whose contents
VirtualBox presents to your VM as if it were a complete hard disk.
This file represents an entire hard disk then, so you can even copy
it to another host and use it with another VirtualBox
installation.</para>
<para>The wizard shows you the following window:</para>
<para><mediaobject>
<imageobject>
width="10cm" />
</imageobject>
</mediaobject></para>
<para>Here you have the following options:</para>
<para><itemizedlist>
<listitem>
<para>To create a new, empty virtual hard disk, press the
<emphasis role="bold">"New"</emphasis> button.</para>
</listitem>
<listitem>
<para>You can pick an <emphasis
role="bold">existing</emphasis> disk image file.</para>
<para>The <emphasis role="bold">drop-down list</emphasis>
presented in the window contains all disk images which are
currently remembered by VirtualBox, probably because they are
currently attached to a virtual machine (or have been in the
past).</para>
<para>Alternatively, you can click on the small <emphasis
role="bold">folder button</emphasis> next to the drop-down
list to bring up a standard file dialog, which allows you to
pick any disk image file on your host disk.</para>
</listitem>
</itemizedlist>Most probably, if you are using VirtualBox for the
first time, you will want to create a new disk image. Hence, press
the "New" button.</para>
<para>This brings up another window, the <emphasis
role="bold">"Create New Virtual Disk Wizard",</emphasis> which helps
you create a new disk image file in the new virtual machine's
folder.</para>
<para>VirtualBox supports two types of image files:<itemizedlist>
<listitem>
<para>A <emphasis role="bold">dynamically allocated
file</emphasis> will only grow in size when the guest actually
stores data on its virtual hard disk. It will therefore
initially be small on the host hard drive and only later grow
to the size specified as it is filled with data.</para>
</listitem>
<listitem>
<para>A <emphasis role="bold">fixed-size file</emphasis> will
immediately occupy the file specified, even if only a fraction
of the virtual hard disk space is actually in use. While
occupying much more space, a fixed-size file incurs less
overhead and is therefore slightly faster than a dynamically
allocated file.</para>
</listitem>
</itemizedlist></para>
<para>For details about the differences, please refer to <xref
linkend="vdidetails" />.</para>
<para>To prevent your physical hard disk from running full,
VirtualBox limits the size of the image file. Still, it needs to be
large enough to hold the contents of your operating system and the
applications you want to install -- for a modern Windows or Linux
guest, you will probably need several gigabytes for any serious
use. The limit of the image file size can be changed later (see <xref
linkend="vboxmanage-modifyvdi"/> for details).</para>
<mediaobject>
<imageobject>
width="10cm" />
</imageobject>
</mediaobject>
<para>After having selected or created your image file, again press
<emphasis role="bold">"Next"</emphasis> to go to the next
page.</para>
</listitem>
<listitem>
<para>After clicking on <emphasis role="bold">"Finish"</emphasis>,
your new virtual machine will be created. You will then see it in
the list on the left side of the Manager window, with the name you
entered initially.</para>
</listitem>
</orderedlist></para>
<note><para>After becoming familiar with the use of wizards, consider using
the Expert Mode available in some wizards. Where available, this is
selectable using a button, and speeds up user processes using
wizards.</para></note>
</sect1>
<sect1>
<title>Running your virtual machine</title>
<para>To start a virtual machine, you have several options:<itemizedlist>
<listitem>
<para>Double-click on its entry in the list within the Manager
window or</para>
</listitem>
<listitem>
<para>select its entry in the list in the Manager window it and
press the "Start" button at the top or</para>
</listitem>
<listitem>
<para>for virtual machines created with VirtualBox 4.0 or later,
navigate to the "VirtualBox VMs" folder in your system user's home
directory, find the subdirectory of the machine you want to start
and double-click on the machine settings file (with a
<computeroutput>.vbox</computeroutput> file extension).</para>
</listitem>
</itemizedlist></para>
<para>This opens up a new window, and the virtual machine which you
selected will boot up. Everything which would normally be seen on the
virtual system's monitor is shown in the window, as can be seen with the
image in <xref linkend="virtintro" />.</para>
<para>In general, you can use the virtual machine much like you would use
a real computer. There are couple of points worth mentioning
however.</para>
<sect2>
<title>Starting a new VM for the first time</title>
<para>When a VM gets started for the first time, another wizard -- the
<emphasis role="bold">"First Start Wizard"</emphasis> -- will pop up to
help you select an <emphasis role="bold">installation medium</emphasis>.
Since the VM is created empty, it would otherwise behave just like a
real computer with no operating system installed: it will do nothing and
display an error message that no bootable operating system was
found.</para>
<para>For this reason, the wizard helps you select a medium to install
an operating system from.</para>
<itemizedlist>
<listitem>
<para>If you have physical CD or DVD media from which you want to
install your guest operating system (e.g. in the case of a Windows
installation CD or DVD), put the media into your host's CD or DVD
drive.</para>
<para>Then, in the wizard's drop-down list of installation media,
select <emphasis role="bold">"Host drive"</emphasis> with the
correct drive letter (or, in the case of a Linux host, device file).
This will allow your VM to access the media in your host drive, and
you can proceed to install from there.</para>
</listitem>
<listitem>
<para>If you have downloaded installation media from the Internet in
the form of an ISO image file (most probably in the case of a Linux
distribution), you would normally burn this file to an empty CD or
DVD and proceed as just described. With VirtualBox however, you can
skip this step and mount the ISO file directly. VirtualBox will then
present this file as a CD or DVD-ROM drive to the virtual machine,
much like it does with virtual hard disk images.</para>
<para>For this case, the wizard's drop-down list contains a list of
installation media that were previously used with VirtualBox.</para>
<para>If your medium is not in the list (especially if you are using
VirtualBox for the first time), select the small folder icon next to
the drop-down list to bring up a standard file dialog, with which
you can pick the image file on your host disks.</para>
</listitem>
</itemizedlist>
<para>In both cases, after making the choices in the wizard, you will be
able to install your operating system.</para>
</sect2>
<sect2 id="keyb_mouse_normal">
<title>Capturing and releasing keyboard and mouse</title>
<para>As of version 3.2, VirtualBox provides a virtual USB tablet device
to new virtual machines through which mouse events are communicated to
the guest operating system. As a result, if you are running a modern
guest operating system that can handle such devices, mouse support may
work out of the box without the mouse being "captured" as described
below; see <xref linkend="settings-motherboard" /> for more
information.</para>
<para>Otherwise, if the virtual machine only sees standard PS/2 mouse
and keyboard devices, since the operating system in the virtual machine
does not "know" that it is not running on a real computer, it expects to
have exclusive control over your keyboard and mouse. This is, however,
not the case since, unless you are running the VM in full screen mode,
your VM needs to share keyboard and mouse with other applications and
possibly other VMs on your host.</para>
<para>As a result, initially after installing a guest operating system
and before you install the Guest Additions (we will explain this in a
minute), only one of the two -- your VM or the rest of your computer --
can "own" the keyboard and the mouse. You will see a
<emphasis>second</emphasis> mouse pointer which will always be confined
to the limits of the VM window. Basically, you activate the VM by
clicking inside it.</para>
<para>To return ownership of keyboard and mouse to your host operating
system, VirtualBox reserves a special key on your keyboard for itself:
the <emphasis role="bold">"host key".</emphasis> By default, this is the
<emphasis>right Control key</emphasis> on your keyboard; on a Mac host,
the default host key is the left Command key. You can change this
default in the VirtualBox Global Settings, see <xref
linkend="globalsettings" />. In any case, the current
setting for the host key is always displayed <emphasis>at the bottom
right of your VM window,</emphasis> should you have forgotten about
it:</para>
<para><mediaobject>
<imageobject>
width="7cm" />
</imageobject>
</mediaobject>In detail, all this translates into the
following:</para>
<para><itemizedlist>
<listitem>
<para>Your <emphasis role="bold">keyboard</emphasis> is owned by
the VM if the VM window on your host desktop has the keyboard
focus (and then, if you have many windows open in your guest
operating system as well, the window that has the focus in your
VM). This means that if you want to type within your VM, click on
the title bar of your VM window first.</para>
<para>To release keyboard ownership, press the Host key (as
explained above, typically the right Control key).</para>
<para>Note that while the VM owns the keyboard, some key sequences
(like Alt-Tab for example) will no longer be seen by the host, but
will go to the guest instead. After you press the host key to
re-enable the host keyboard, all key presses will go through the
host again, so that sequences like Alt-Tab will no longer reach
the guest. For technical reasons it may not be possible for the
VM to get all keyboard input even when it does own the keyboard.
Examples of this are the Ctrl-Alt-Del sequence on Windows hosts
or single keys grabbed by other applications on X11 hosts like
the GNOME desktop's "Control key highlights mouse pointer"
functionality.</para>
</listitem>
<listitem>
<para>Your <emphasis role="bold">mouse</emphasis> is owned by the
VM only after you have clicked in the VM window. The host mouse
pointer will disappear, and your mouse will drive the guest's
pointer instead of your normal mouse pointer.</para>
<para>Note that mouse ownership is independent of that of the
keyboard: even after you have clicked on a titlebar to be able to
type into the VM window, your mouse is not necessarily owned by
the VM yet.</para>
<para>To release ownership of your mouse by the VM, also press the
Host key.</para>
</listitem>
</itemizedlist></para>
<para>As this behavior can be inconvenient, VirtualBox provides a set of
tools and device drivers for guest systems called the "VirtualBox Guest
Additions" which make VM keyboard and mouse operation a lot more
seamless. Most importantly, the Additions will get rid of the second
"guest" mouse pointer and make your host mouse pointer work directly in
the guest.</para>
<para>This will be described later in <xref
linkend="guestadditions" />.</para>
</sect2>
<sect2 id="specialcharacters">
<title>Typing special characters</title>
<para>Operating systems expect certain key combinations to initiate
certain procedures. Some of these key combinations may be difficult to
enter into a virtual machine, as there are three candidates as to who
receives keyboard input: the host operating system, VirtualBox, or the
guest operating system. Who of these three receives keypresses depends
on a number of factors, including the key itself.</para>
<itemizedlist>
<listitem>
<para>Host operating systems reserve certain key combinations for
themselves. For example, it is impossible to enter the <emphasis
role="bold">Ctrl+Alt+Delete</emphasis> combination if you want to
reboot the guest operating system in your virtual machine, because
this key combination is usually hard-wired into the host OS (both
Windows and Linux intercept this), and pressing this key combination
will therefore reboot your <emphasis>host</emphasis>.</para>
<para>Also, on Linux and Solaris hosts, which use the X Window
System, the key combination <emphasis
role="bold">Ctrl+Alt+Backspace</emphasis> normally resets the X
server (to restart the entire graphical user interface in case it
got stuck). As the X server intercepts this combination, pressing it
will usually restart your <emphasis>host</emphasis> graphical user
interface (and kill all running programs, including VirtualBox, in
the process).</para>
<para>Third, on Linux hosts supporting virtual terminals, the key
combination <emphasis role="bold">Ctrl+Alt+Fx</emphasis> (where Fx
is one of the function keys from F1 to F12) normally allows to
switch between virtual terminals. As with Ctrl+Alt+Delete, these
combinations are intercepted by the host operating system and
therefore always switch terminals on the
<emphasis>host</emphasis>.</para>
<para>If, instead, you want to send these key combinations to the
<emphasis>guest</emphasis> operating system in the virtual machine,
you will need to use one of the following methods:</para>
<itemizedlist>
<listitem>
<para>Use the items in the "Machine" menu of the virtual machine
window. There you will find "Insert Ctrl+Alt+Delete" and
"Ctrl+Alt+Backspace"; the latter will only have an effect with
Linux or Solaris guests, however.</para>
</listitem>
<listitem>
<para>Press special key combinations with the Host key (normally
the right Control key), which VirtualBox will then translate for
the virtual machine:<itemizedlist>
<listitem>
<para><emphasis role="bold">Host key + Del</emphasis> to
send Ctrl+Alt+Del (to reboot the guest);</para>
</listitem>
<listitem>
<para><emphasis role="bold">Host key +
Backspace</emphasis> to send Ctrl+Alt+Backspace (to
restart the graphical user interface of a Linux or Solaris
guest);</para>
</listitem>
<listitem>
<para><emphasis role="bold">Host key + F1</emphasis> (or
other function keys) to simulate Ctrl+Alt+F1 (or other
function keys, i.e. to switch between virtual terminals in
a Linux guest).</para>
</listitem>
</itemizedlist></para>
</listitem>
</itemizedlist>
</listitem>
<listitem>
<para>For some other keyboard combinations such as <emphasis
role="bold">Alt-Tab</emphasis> (to switch between open windows),
VirtualBox allows you to configure whether these combinations will
affect the host or the guest, if a virtual machine currently has the
focus. This is a global setting for all virtual machines and can be
found under "File" -> "Preferences" -> "Input" ->
"Auto-capture keyboard".</para>
</listitem>
</itemizedlist>
</sect2>
<sect2>
<title>Changing removable media</title>
<para>While a virtual machine is running, you can change removable media
in the "Devices" menu of the VM's window. Here you can select in detail
what VirtualBox presents to your VM as a CD, DVD, or floppy.</para>
<para>The settings are the same as would be available for the VM in the
"Settings" dialog of the VirtualBox main window, but since that dialog
is disabled while the VM is in the "running" or "saved" state, this
extra menu saves you from having to shut down and restart the VM every
time you want to change media.</para>
<para>Hence, in the "Devices" menu, VirtualBox allows you to attach the
host drive to the guest or select a floppy or DVD image using the Disk
Image Manager, all as described in <xref
linkend="configbasics" />.</para>
</sect2>
<sect2 id="intro-resize-window">
<title>Resizing the machine's window</title>
<para>You can resize the virtual machine's window when it is running. In
that case, one of three things will happen:<orderedlist>
<listitem>
<para>If you have <emphasis role="bold">"scale mode"</emphasis>
enabled, then the virtual machine's screen will be scaled to the
size of the window. This can be useful if you have many machines
running and want to have a look at one of them while it is running
in the background. Alternatively, it might be useful to enlarge a
window if the VM's output screen is very small, for example
because you are running an old operating system in it.</para>
<para>To enable scale mode, press the <emphasis role="bold">host
key + C</emphasis>, or select "Scale mode" from the "Machine" menu
in the VM window. To leave scale mode, press the host key + C
again.</para>
<para>The aspect ratio of the guest screen is preserved when
resizing the window. To ignore the aspect ratio, press Shift
during the resize operation.</para>
<para>Please see <xref linkend="KnownIssues" /> for additional
remarks.</para>
</listitem>
<listitem>
<para>If you have the Guest Additions installed and they support
automatic <emphasis role="bold">resizing</emphasis>, the Guest
Additions will automatically adjust the screen resolution of the
guest operating system. For example, if you are running a Windows
guest with a resolution of 1024x768 pixels and you then resize the
VM window to make it 100 pixels wider, the Guest Additions will
change the Windows display resolution to 1124x768.</para>
<para>Please see <xref linkend="guestadditions" /> for more
information about the Guest Additions.</para>
</listitem>
<listitem>
<para>Otherwise, if the window is bigger than the VM's screen, the
screen will be centered. If it is smaller, then scroll bars will
be added to the machine window.</para>
</listitem>
</orderedlist></para>
</sect2>
<sect2>
<title>Saving the state of the machine</title>
<para>When you click on the "Close" button of your virtual machine
window (at the top right of the window, just like you would close any
other window on your system), VirtualBox asks you whether you want to
"save" or "power off" the VM. (As a shortcut, you can also press the
Host key together with "Q".)</para>
<para><mediaobject>
<imageobject>
width="11cm" />
</imageobject>
</mediaobject>The difference between these three options is crucial.
They mean:</para>
<itemizedlist>
<listitem>
<para><emphasis role="bold">Save the machine state:</emphasis> With
this option, VirtualBox "freezes" the virtual machine by completely
saving its state to your local disk.</para>
<para>When you start the VM again later, you will find that the VM
continues exactly where it was left off. All your programs will
still be open, and your computer resumes operation. Saving the state
of a virtual machine is thus in some ways similar to suspending a
laptop computer (e.g. by closing its lid).</para>
</listitem>
<listitem>
<para><emphasis role="bold">Send the shutdown signal.</emphasis>
This will send an ACPI shutdown signal to the virtual machine, which
has the same effect as if you had pressed the power button on a real
computer. So long as the VM is running a fairly modern operating
system, this should trigger a proper shutdown mechanism from within
the VM.</para>
</listitem>
<listitem>
<para><emphasis role="bold">Power off the machine:</emphasis> With
this option, VirtualBox also stops running the virtual machine, but
<emphasis>without</emphasis> saving its state.<warning>
<para>This is equivalent to pulling the power plug on a real
computer without shutting it down properly. If you start the
machine again after powering it off, your operating system will
have to reboot completely and may begin a lengthy check of its
(virtual) system disks. As a result, this should not normally be
done, since it can potentially cause data loss or an
inconsistent state of the guest system on disk.</para>
</warning></para>
<para>As an exception, if your virtual machine has any snapshots
(see the next chapter), you can use this option to quickly <emphasis
role="bold">restore the current snapshot</emphasis> of the virtual
machine. In that case, powering off the machine will not disrupt its
state, but any changes made since that snapshot was taken will be
lost.</para>
</listitem>
</itemizedlist>
<para>The <emphasis role="bold">"Discard"</emphasis> button in the
VirtualBox Manager window discards a virtual machine's saved state. This
has the same effect as powering it off, and the same warnings
apply.</para>
</sect2>
</sect1>
<sect1 id="gui-vmgroups">
<title>Using VM groups</title>
<para>VM groups enable the user to create ad hoc groups of VMs, and to
manage and perform functions on them collectively, as well as individually.
There are a number of features relating to groups:</para>
<orderedlist>
<listitem>
<para>
Create a group using GUI option 1) Drag one VM on top of another
VM.
</para>
<para>
Create a group using GUI option 2) Select multiple VMs and select
"Group" on the right click menu, as follows:
</para>
<para><mediaobject>
<imageobject>
width="10cm" />
</imageobject>
</mediaobject></para>
</listitem>
<listitem>
<para>
Command line option 1) Create a group and assign a VM:
<screen>VBoxManage modifyvm "Fred" --groups "/TestGroup"</screen>
creates a group "TestGroup" and attaches the VM "Fred" to that group.
</para>
<para>
Command line option 2) Detach a VM from the group, and delete the group
if empty: <screen>VBoxManage modifyvm "Fred" --groups ""</screen>
It detaches all groups from the VM "Fred" and deletes the empty group.
</para>
</listitem>
<listitem>
<para>
Multiple groups e.g.:
<screen>VBoxManage modifyvm "Fred" --groups "/TestGroup,/TestGroup2"</screen>
It creates the groups "TestGroup" and "TestGroup2" (if they don't exist yet)
and attaches the VM "Fred" to both of them.
</para>
</listitem>
<listitem>
<para>
Nested groups -- hierarchy of groups e.g.:
It attaches the VM "Fred" to the subgroup "TestGroup2" of the "TestGroup"
group.
</para>
</listitem>
<listitem>
<para>
Summary of group commands: Start, Pause, Reset, Close (save state,
send shutdown signal, poweroff), Discard Saved State, Show in File
System, Sort.
</para>
</listitem>
</orderedlist>
</sect1>
<sect1 id="snapshots">
<title>Snapshots</title>
<para>With snapshots, you can save a particular state of a virtual machine
for later use. At any later time, you can revert to that state, even
though you may have changed the VM considerably since then. A snapshot of
a virtual machine is thus similar to a machine in "saved" state, as
described above, but there can be many of them, and these saved states are
preserved.</para>
<para>You can see the snapshots of a virtual machine by first selecting a
machine in the VirtualBox Manager and then clicking on the "Snapshots"
button at the top right. Until you take a snapshot of the machine, the
list of snapshots will be empty except for the "Current state" item, which
represents the "Now" point in the lifetime of the virtual machine.</para>
<sect2>
<title>Taking, restoring and deleting snapshots</title>
<para>There are three operations related to snapshots:<orderedlist>
<listitem>
<para>You can <emphasis role="bold">take a snapshot</emphasis>.
This makes a copy of the machine's current state, to which you can
go back at any given time later.<itemizedlist>
<listitem>
<para>If your VM is currently running, select "Take
snapshot" from the "Machine" pull-down menu of the VM
window.</para>
</listitem>
<listitem>
<para>If your VM is currently in either the "saved" or the
"powered off" state (as displayed next to the VM in the
VirtualBox main window), click on the "Snapshots" tab on the
top right of the main window, and then<itemizedlist>
<listitem>
<para>either on the small camera icon (for "Take
snapshot") or</para>
</listitem>
<listitem>
<para>right-click on the "Current State" item in the
list and select "Take snapshot" from the menu.</para>
</listitem>
</itemizedlist></para>
</listitem>
</itemizedlist></para>
<para>In any case, a window will pop up and ask you for a snapshot
name. This name is purely for reference purposes to help you
remember the state of the snapshot. For example, a useful name
would be "Fresh installation from scratch, no Guest Additions", or
"Service Pack 3 just installed". You can also add a longer text in
the "Description" field if you want.</para>
<para>Your new snapshot will then appear in the snapshots list.
Underneath your new snapshot, you will see an item called "Current
state", signifying that the current state of your VM is a
variation based on the snapshot you took earlier. If you later
take another snapshot, you will see that they will be displayed in
sequence, and each subsequent snapshot is derived from an earlier
one:<mediaobject>
<imageobject>
width="12cm" />
</imageobject>
</mediaobject></para>
<para>VirtualBox imposes no limits on the number of snapshots you
can take. The only practical limitation is disk space on your
host: each snapshot stores the state of the virtual machine and
thus occupies some disk space. (See the next section for details
on what exactly is stored in a snapshot.)</para>
</listitem>
<listitem>
<para>You can <emphasis role="bold">restore a snapshot</emphasis>
by right-clicking on any snapshot you have taken in the list of
snapshots. By restoring a snapshot, you go back (or forward) in
time: the current state of the machine is lost, and the machine is
restored to the exact state it was in when the snapshot was
taken.<footnote>
<para>Both the terminology and the functionality of restoring
snapshots has changed with VirtualBox 3.1. Before that
version, it was only possible to go back to the very last
snapshot taken -- not earlier ones, and the operation was
called "Discard current state" instead of "Restore last
snapshot". The limitation has been lifted with version 3.1. It
is now possible to restore <emphasis>any</emphasis> snapshot,
going backward and forward in time.</para>
</footnote></para>
<note>
<para>Restoring a snapshot will affect the virtual hard drives
that are connected to your VM, as the entire state of the
virtual hard drive will be reverted as well. This means also
that all files that have been created since the snapshot and all
other file changes <emphasis>will be lost. </emphasis>In order
to prevent such data loss while still making use of the snapshot
feature, it is possible to add a second hard drive in
"write-through" mode using the
<computeroutput>VBoxManage</computeroutput> interface and use it
to store your data. As write-through hard drives are
<emphasis>not</emphasis> included in snapshots, they remain
unaltered when a machine is reverted. See <xref
linkend="hdimagewrites" os="" /> for details.</para>
</note>
<para>To avoid losing the current state when restoring a snapshot,
you can create a new snapshot before the restore.</para>
<para>By restoring an earlier snapshot and taking more snapshots
from there, it is even possible to create a kind of alternate
reality and to switch between these different histories of the
virtual machine. This can result in a whole tree of virtual
machine snapshots, as shown in the screenshot above.</para>
</listitem>
<listitem>
<para>You can also <emphasis role="bold">delete a
snapshot</emphasis>, which will not affect the state of the
virtual machine, but only release the files on disk that
VirtualBox used to store the snapshot data, thus freeing disk
space. To delete a snapshot, right-click on it in the snapshots
tree and select "Delete". As of VirtualBox 3.2, snapshots can be
deleted even while a machine is running.<note>
<para>Whereas taking and restoring snapshots are fairly quick
operations, deleting a snapshot can take a considerable amount
of time since large amounts of data may need to be copied
between several disk image files. Temporary disk files may
also need large amounts of disk space while the operation is
in progress.</para>
</note></para>
<para>There are some situations which cannot be handled while a VM
is running, and you will get an appropriate message that you need
to perform this snapshot deletion when the VM is shut down.</para>
</listitem>
</orderedlist></para>
</sect2>
<sect2>
<title>Snapshot contents</title>
<para>Think of a snapshot as a point in time that you have preserved.
More formally, a snapshot consists of three things:<itemizedlist>
<listitem>
<para>It contains a complete copy of the VM settings, including
the hardware configuration, so that when you restore a snapshot,
the VM settings are restored as well. (For example, if you changed
the hard disk configuration or the VM's system settings, that
change is undone when you restore the snapshot.)</para>
<para>The copy of the settings is stored in the machine
configuration, an XML text file, and thus occupies very little
space.</para>
</listitem>
<listitem>
<para>The complete state of all the virtual disks attached to the
machine is preserved. Going back to a snapshot means that all
changes that had been made to the machine's disks -- file by file,
bit by bit -- will be undone as well. Files that were since
created will disappear, files that were deleted will be restored,
changes to files will be reverted.</para>
<para>(Strictly speaking, this is only true for virtual hard disks
in "normal" mode. As mentioned above, you can configure disks to
behave differently with snapshots; see <xref
linkend="hdimagewrites" />. Even more formally and technically
correct, it is not the virtual disk itself that is restored when a
snapshot is restored. Instead, when a snapshot is taken,
VirtualBox creates differencing images which contain only the
changes since the snapshot were taken, and when the snapshot is
restored, VirtualBox throws away that differencing image, thus
going back to the previous state. This is both faster and uses
less disk space. For the details, which can be complex, please see
<xref linkend="diffimages" />.)</para>
<para>Creating the differencing image as such does not occupy much
space on the host disk initially, since the differencing image
will initially be empty (and grow dynamically later with each
write operation to the disk). The longer you use the machine after
having created the snapshot, however, the more the differencing
image will grow in size.</para>
</listitem>
<listitem>
<para>Finally, if you took a snapshot while the machine was
running, the memory state of the machine is also saved in the
snapshot (the same way the memory can be saved when you close the
VM window). When you restore such a snapshot, execution resumes at
exactly the point when the snapshot was taken.</para>
<para>The memory state file can be as large as the memory size of
the virtual machine and will therefore occupy quite some disk
space as well.</para>
</listitem>
</itemizedlist></para>
</sect2>
</sect1>
<sect1 id="configbasics">
<title>Virtual machine configuration</title>
<para>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.</para>
<para>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.</para>
<note>
<para>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.</para>
</note>
<para>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 <xref
linkend="BasicConcepts" />. Even more parameters are available with the
VirtualBox command line interface; see <xref
linkend="vboxmanage" />.</para>
</sect1>
<sect1>
<title>Removing virtual machines</title>
<para>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.</para>
<para>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.</para>
<para>The "Remove" menu item is disabled while a machine is
running.</para>
</sect1>
<sect1 id="clone">
<title>Cloning virtual machines</title>
<para>To experiment with a VM configuration, test different guest OS levels
or to simply backup a VM, VirtualBox can create a full or a linked copy of
an existing VM.<footnote>Cloning support was introduced with VirtualBox
4.1.</footnote></para>
<para>A wizard will guide you through the clone process:</para>
<mediaobject>
<imageobject>
width="10cm" />
</imageobject>
</mediaobject>
<para>This wizard can be invoked from the context menu of the Manager's VM
list (select "Clone") or the "Snapshots" view of the selected VM. First
choose a new name for the clone. When you select <emphasis
role="bold">Reinitialize the MAC address of all network cards</emphasis>
every network card get a new MAC address assigned. This is useful when
both, the source VM and the cloned VM, have to operate on the same network.
If you leave this unchanged, all network cards have the same MAC address
like the one in the source VM. Depending on how you invoke the wizard you
have different choices for the cloning operation. First you need to decide
if the clone should be linked to the source VM or a fully independent clone
should be created:</para>
<itemizedlist>
<listitem>
<para><emphasis role="bold">Full clone:</emphasis> In this mode all
depending disk images are copied to the new VM folder. The clone
can fully operate without the source VM.
</para>
</listitem>
<listitem>
<para><emphasis role="bold">Linked clone:</emphasis> In this mode new
differencing disk images are created where the parent disk images
are the source disk images. If you selected the current state of
the source VM as clone point, a new snapshot will be created
implicitly.
</para>
</listitem>
</itemizedlist>
<para>After selecting the clone mode, you need to decide about what exactly
should be cloned. You can always create a clone of the <emphasis
role="italic">current state</emphasis> only or <emphasis
role="italic">all</emphasis>. When you select <emphasis
role="italic">all</emphasis>, the current state and in addition all
snapshots are cloned. Have you started from a snapshot which has additional
children, you can also clone the <emphasis role="italic">current state and
all children</emphasis>. This creates a clone starting with this
snapshot and includes all child snaphots.</para>
<para>The clone operation itself can be a lengthy operation depending on
the size and count of the attached disk images. Also keep in mind that
every snapshot has differencing disk images attached, which need to be
cloned as well.</para>
<para>The "Clone" menu item is disabled while a machine is running.</para>
<para>For how to clone a VM at the command line, please see <xref
linkend="vboxmanage-clonevm" />.</para>
</sect1>
<sect1 id="ovf">
<title>Importing and exporting virtual machines</title>
<para>VirtualBox can import and export virtual machines in the
industry-standard Open Virtualization Format (OVF).<footnote>
<para>OVF support was originally introduced with VirtualBox 2.2 and
has seen major improvements with every version since.</para>
</footnote></para>
<para>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 <emphasis role="bold">virtual appliances</emphasis>: 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>
<para>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 <xref
linkend="KnownIssues" />.</para>
</note></para>
<para>Appliances in OVF format can appear in two variants:<orderedlist>
<listitem>
<para>They can come in several files, as one or several disk images,
typically in the widely-used VMDK format (see <xref
linkend="vdidetails" />) and a textual description file in an XML
dialect with an <computeroutput>.ovf</computeroutput> extension.
These files must then reside in the same directory for VirtualBox to
be able to import them.</para>
</listitem>
<listitem>
<para>Alternatively, the above files can be packed together into a
single archive file, typically with an
<computeroutput>.ova</computeroutput> extension. (Such archive files
use a variant of the TAR archive format and can therefore be
unpacked outside of VirtualBox with any utility that can unpack
standard TAR files.)</para>
</listitem>
</orderedlist></para>
<para>To <emphasis role="bold">import</emphasis> an appliance in one of
<para>Starting with version 4.0, VirtualBox creates file type
associations for OVF and OVA files on your host operating
system.</para>
</footnote> Alternatively, select "File" -> "Import appliance" from
the Manager window. In the file dialog that comes up, navigate to the file
with either the <computeroutput>.ovf</computeroutput> or the
<computeroutput>.ova</computeroutput> file extension.</para>
<para>If VirtualBox can handle the file, a dialog similar to the following
will appear:</para>
<para><mediaobject>
<imageobject>
width="12cm" />
</imageobject>
</mediaobject>This presents the virtual machines described in the OVF
file and allows you to change the virtual machine settings by
double-clicking on the description items. Once you click on <emphasis
role="bold">"Import"</emphasis>, VirtualBox will copy the disk images and
create local virtual machines with the settings described in the dialog.
These will then show up in the Manager's list of virtual machines.</para>
<para>Note that since disk images tend to be big, and VMDK images that
come with virtual appliances are typically shipped in a special compressed
format that is unsuitable for being used by virtual machines directly, the
images will need to be unpacked and copied first, which can take a few
minutes.</para>
<para>For how to import an image at the command line, please see <xref
linkend="vboxmanage-import" />.</para>
<para>Conversely, to <emphasis role="bold">export</emphasis> virtual
machines that you already have in VirtualBox, select "File" -> "Export
appliance". A different dialog window shows up that allows you to combine
several virtual machines into an OVF appliance. Then, select the target
location where the target files should be stored, and the conversion
process begins. This can again take a while.</para>
<para>For how to export an image at the command line, please see <xref
linkend="vboxmanage-export" />.<note>
<para>OVF cannot describe snapshots that were taken for a virtual
machine. As a result, when you export a virtual machine that has
snapshots, only the current state of the machine will be exported, and
the disk images in the export will have a "flattened" state identical
to the current state of the virtual machine.</para>
</note></para>
</sect1>
<sect1 id="globalsettings">
<title>Global Settings</title>
<para>The global settings dialog can be reached through the
<emphasis role="bold">File</emphasis> menu, selecting the
<emphasis role="bold">Preferences...</emphasis> item. It offers a selection
of settings which apply to all virtual machines of the current user or in
the case of <emphasis role="bold">Extensions</emphasis> to the entire
system:
<orderedlist>
<listitem>
<para><emphasis role="bold">General</emphasis> Enables the user to
Authentication Library.</para>
</listitem>
<listitem>
<para><emphasis role="bold">Input</emphasis> Enables the user to
specify the Host Key. It identifies the key that toggles whether the
cursor is in the focus of the VM or the Host operating system
windows (see <xref linkend="keyb_mouse_normal"/>) and which is also
used to trigger certain VM actions (see <xref
linkend="specialcharacters"/>)</para>
</listitem>
<listitem>
<para><emphasis role="bold">Update</emphasis> Enables the user
to specify various settings for Automatic Updates.</para>
</listitem>
<listitem>
<para><emphasis role="bold">Language</emphasis> Enables the user to
specify the GUI language.</para>
</listitem>
<listitem>
<para><emphasis role="bold">Display</emphasis> Enables the user to
specify the screen resolution, and its width and height.</para>
</listitem>
<listitem>
<para><emphasis role="bold">Network</emphasis> Enables the user to
configure the details of Host Only Networks.</para>
</listitem>
<listitem>
<para><emphasis role="bold">Extensions</emphasis> Enables the user
to list and manage the installed extension packages.</para>
</listitem>
<listitem>
<para><emphasis role="bold">Proxy</emphasis> Enables the user to
configure a HTTP Proxy Server.</para>
</listitem>
</orderedlist></para>
</sect1>
<sect1 id="frontends">
<title>Alternative front-ends</title>
<para>As briefly mentioned in <xref linkend="features-overview" />,
VirtualBox has a very flexible internal design that allows for using
multiple interfaces to control the same virtual machines. To illustrate,
you can, for example, start a virtual machine with the VirtualBox Manager
window and then stop it from the command line. With VirtualBox's support
for the Remote Desktop Protocol (RDP), you can even run virtual machines
remotely on a headless server and have all the graphical output redirected
over the network.</para>
<para>In detail, the following front-ends are shipped in the standard
VirtualBox package:</para>
<para><orderedlist>
<listitem>
<para><computeroutput>VirtualBox</computeroutput> is the VirtualBox
Manager. This graphical user interface uses the Qt toolkit; most of
this User Manual is dedicated to describing it. While this is the
easiest to use, some of the more advanced VirtualBox features are
kept away from it to keep it simple.</para>
</listitem>
<listitem>
<para><computeroutput>VBoxManage</computeroutput> is our
command-line interface for automated and very detailed control of
every aspect of VirtualBox. It is described in <xref
linkend="vboxmanage" />.</para>
</listitem>
<listitem>
<para><computeroutput>VBoxSDL</computeroutput> is an alternative,
simple graphical front-end with an intentionally limited feature
set, designed to only display virtual machines that are controlled
in detail with <computeroutput>VBoxManage</computeroutput>. This is
interesting for business environments where displaying all the bells
and whistles of the full GUI is not feasible.
<computeroutput>VBoxSDL</computeroutput> is described in <xref
linkend="vboxsdl" />.</para>
</listitem>
<listitem>
<para>Finally, <computeroutput>VBoxHeadless</computeroutput> is yet
another front-end that produces no visible output on the host at
all, but merely acts as a RDP server if the VirtualBox Remote
Desktop Extension (VRDE) is installed. As opposed to the other
graphical interfaces, the headless front-end requires no graphics
support. This is useful, for example, if you want to host your
virtual machines on a headless Linux server that has no X Window
system installed. For details, see <xref
linkend="vboxheadless" />.</para>
</listitem>
</orderedlist>If the above front-ends still do not satisfy your
particular needs, it is possible to create yet another front-end to the
complex virtualization engine that is the core of VirtualBox, as the
VirtualBox core neatly exposes all of its features in a clean API; please
refer to <xref linkend="VirtualBoxAPI" />.</para>
</sect1>
</chapter>