source: vbox/trunk/doc/manual/en_US/user_Introduction.xml@ 74865

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<chapter id="Introduction">

  <title>First Steps</title>

  <para>
    Welcome to Oracle VM VirtualBox.
  </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 how VirtualBox, installed on a Mac
    computer, is running Windows 8 in a virtual machine window:
  </para>

  <mediaobject>
    <imageobject>
      <imagedata align="center" fileref="images/vm-vista-running.png"
                   width="14cm" />
    </imageobject>
  </mediaobject>

  <para>
    In this User Manual, we will 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 is new in this release, there is a
    detailed list in <xref
  linkend="ChangeLog" />.
  </para>

  <sect1 id="virt-why-useful">

    <title>Why is Virtualization Useful?</title>

    <para>
      The techniques and features that VirtualBox provides are useful in
      the following 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, such as
          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,
          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 , such as prolems after
          installing software or infecting the guest with a virus, you
          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>

    <itemizedlist>

      <listitem>
        <para>
          <emphasis role="strong">Host operating system (host
          OS).</emphasis> 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.
          See <xref linkend="hostossupport" />.
        </para>

        <para>
          Most of the time, this manual discusses all VirtualBox
          versions together. There may be platform-specific differences
          which we will point out where appropriate.
        </para>
      </listitem>

      <listitem>
        <para>
          <emphasis role="strong"> Guest operating system (guest
          OS).</emphasis> This is the operating system that is running
          inside the virtual machine. Theoretically, VirtualBox can run
          any x86 operating system. such as DOS, Windows, OS/2, FreeBSD,
          and 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 include the most common
          operating systems.
        </para>

        <para>
          See <xref linkend="guestossupport" />.
        </para>
      </listitem>

      <listitem>
        <para>
          <emphasis role="strong">Virtual machine (VM).</emphasis> 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, such as: how much memory the VM
          should have, what hard disks VirtualBox should virtualize
          through which container files, what CDs are mounted. They also
          include state information, such as: whether the VM is
          currently running, saved, if the VM has snapshots. 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>
      </listitem>

      <listitem>
        <para>
          <emphasis role="strong">Guest Additions.</emphasis> 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. See
          <xref
          linkend="guestadditions" />.
        </para>
      </listitem>

    </itemizedlist>

  </sect1>

  <sect1 id="features-overview">

    <title>Features Overview</title>

    <para>
      The following is 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
          See <xref linkend="hostossupport" />.
        </para>

        <para>
          VirtualBox is a so-called <emphasis>hosted</emphasis>
          hypervisor, sometimes referred to as a <emphasis>type
          2</emphasis> hypervisor. Whereas a
          <emphasis>bare-metal</emphasis> or <emphasis>type 1</emphasis>
          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), an
          industry standard created for this purpose. You can even
          import OVFs that were created with a different virtualization
          software. See <xref
            linkend="ovf" />.
        </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. See
          <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. See
          <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. See <xref
        linkend="sharedfolders" />.
        </para>
      </listitem>

      <listitem>
        <para>
          <emphasis role="bold">Great hardware support.</emphasis> Among
          others, VirtualBox supports the following:
        </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. 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 parallel ports
              and an Input/Output Advanced Programmable Interrupt
              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>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, for example 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. 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. 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. This means you can have 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: 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" />.
        </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. See
          <xref linkend="VirtualBoxAPI" />.
        </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:
        </para>

        <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" />.
            </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" />.
            </para>
          </listitem>

        </itemizedlist>
      </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 hosts:</emphasis>

          <footnote>

            <para>
              Support for 64-bit Windows was added with VirtualBox 1.5.
              Support for Windows XP was removed with VirtualBox 5.0.
              Support for Windows Vista was removed with VirtualBox 5.2.
            </para>

          </footnote>
        </para>

        <itemizedlist>

          <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 10 RTM build 10240 (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>

          <listitem>
            <para>
              Windows Server 2016 (64-bit)
            </para>
          </listitem>

        </itemizedlist>
      </listitem>

      <listitem>
        <para>
          <emphasis role="bold">Mac OS X hosts (64-bit):</emphasis>

          <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. Support
              for Mac OS X 10.7 (Lion) and earlier was removed with
              VirtualBox 5.0. Support for Mac OS X 10.8 (Mountain Lion)
              was removed with VirtualBox 5.1. Support for Mac OS X 10.9
              (Mavericks) was removed with VirtualBox 5.2.
            </para>

          </footnote>
        </para>

        <itemizedlist>

          <listitem>
            <para>
              10.10 (Yosemite)
            </para>
          </listitem>

          <listitem>
            <para>
              10.11 (El Capitan)
            </para>
          </listitem>

          <listitem>
            <para>
              10.12 (Sierra)
            </para>
          </listitem>

          <listitem>
            <para>
              10.13 (High Sierra)
            </para>
          </listitem>

        </itemizedlist>

        <para>
          Intel hardware is required. See also
          <xref
        linkend="KnownIssues" />.
        </para>
      </listitem>

      <listitem>
        <para>
          <emphasis role="bold">Linux hosts (32-bit and 64-bit).
          Includes the following:</emphasis>

          <footnote>

            <para>
              Support for 64-bit Linux was added with VirtualBox 1.4.
            </para>

          </footnote>
        </para>

        <itemizedlist>

          <listitem>
            <para>
              Ubuntu 14.04 LTS, 16.04 LTS, and 17.04
            </para>
          </listitem>

          <listitem>
            <para>
              Debian GNU/Linux 7 ("Wheezy"), 8 ("Jessie"), and 9
              ("Stretch")
            </para>
          </listitem>

          <listitem>
            <para>
              Oracle Enterprise Linux 5, Oracle Linux 6, and 7
            </para>
          </listitem>

          <listitem>
            <para>
              Redhat Enterprise Linux 5, 6, and 7
            </para>
          </listitem>

          <listitem>
            <para>
              Fedora 25 and 26
            </para>
          </listitem>

          <listitem>
            <para>
              Gentoo Linux
            </para>
          </listitem>

          <listitem>
            <para>
              openSUSE 13.2
            </para>
          </listitem>

        </itemizedlist>

        <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 hosts (64-bit only).</emphasis>
          The following versions are supported with the restrictions
          listed in <xref
        linkend="KnownIssues" />:
        </para>

        <itemizedlist>

          <listitem>
            <para>
              Solaris 11
            </para>
          </listitem>

          <listitem>
            <para>
              Solaris 10 (U10 and higher)
            </para>
          </listitem>

        </itemizedlist>
      </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>experimental</emphasis> is not supported. Feedback and
      suggestions about such features are welcome.
    </para>

  </sect1>

  <sect1 id="hostcpurequirements">

    <title>Host CPU Requirements</title>

    <para>
      SSE2 is required starting with VirtualBox version 5.2.10 and
      version 5.1.24.
    </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, see <xref linkend="installation" /> for
      details about the various installation methods.
    </para>

    <para>
      Starting with version 4.0, VirtualBox is split into several
      components:
    </para>

    <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 a single extension pack, available from:
          <ulink
          url="http://www.virtualbox.org">http://www.virtualbox.org</ulink>.
          The extension pack provides the following added functionality:
        </para>

        <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
              <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>

          <listitem>
            <para>
              Disk image encryption with AES algorithm. See
              <xref linkend="diskencryption" />.
            </para>
          </listitem>

        </orderedlist>

        <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,
          start the VirtualBox Manager, as shown in
          <xref linkend="intro-starting"/>. From the
          <emphasis role="bold">File</emphasis> menu, select
          <emphasis role="bold">Preferences</emphasis>. In the window
          that displays, go to the
          <emphasis role="bold">Extensions</emphasis> category. This
          shows you the extensions which are currently installed, and
          enables you to remove a package or add a new package.
        </para>

        <para>
          Alternatively, you can use the VBoxManage command line. See
          <xref linkend="vboxmanage-extpack" />.
        </para>
      </listitem>

    </orderedlist>

  </sect1>

  <sect1 id="intro-starting">

    <title>Starting VirtualBox</title>

    <para>
      After installation, you can start VirtualBox as follows:
    </para>

    <itemizedlist>

      <listitem>
        <para>
          On a Windows host, in the Programs menu, click on the item in
          the <emphasis role="bold">VirtualBox</emphasis> group. On
          Vista or Windows 7, you can also type
          <computeroutput>VirtualBox</computeroutput> 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
          <emphasis role="bold">VirtualBox</emphasis> 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>
      When you start VirtualBox for the first time, a window like the
      following is displayed:
    </para>

    <mediaobject>
      <imageobject>
        <imagedata align="center" fileref="images/virtualbox-main-empty.png"
                     width="10cm" />
      </imageobject>
    </mediaobject>

    <para>
      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 do not 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 is another example:
    </para>

    <mediaobject>
      <imageobject>
        <imagedata align="center" fileref="images/virtualbox-main.png"
                     width="10cm" />
      </imageobject>
    </mediaobject>

  </sect1>

  <sect1 id="gui-createvm">

    <title>Creating Your First Virtual Machine</title>

    <para>
      Click on the <emphasis role="bold">New</emphasis> 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>
          <imagedata align="center" fileref="images/create-vm-1.png"
                     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:
    </para>

    <orderedlist>

      <listitem>
        <para>
          The <emphasis role="bold">Name</emphasis> of the VM 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 can be used, bear in mind that if you create 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", for example.
        </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
          <emphasis role="bold">Other</emphasis>. 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>

        <caution>
          <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>
        </caution>

        <para>
          A Windows XP guest will require at least a few hundred MB of
          RAM to run properly, and Windows Vista will not install with
          less than 512 MB. If you want to run graphics-intensive
          applications in your VM, you may require even more RAM.
        </para>

        <para>
          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. 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" />, 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 displays the following window:
        </para>

        <para>
          <mediaobject>
            <imageobject>
              <imagedata align="center" fileref="images/create-vm-2.png"
                           width="10cm" />
            </imageobject>
          </mediaobject>
        </para>

        <para>
          At this screen, you have the following options:
        </para>

        <itemizedlist>

          <listitem>
            <para>
              To create a new, empty virtual hard disk, click the
              <emphasis role="bold">New</emphasis> button.
            </para>
          </listitem>

          <listitem>
            <para>
              You can pick an
              <emphasis
               >existing</emphasis> disk image
              file.
            </para>

            <para>
              The drop-down list presented in the window lists all disk
              images which are currently remembered by VirtualBox. These
              disk images are currently attached to a virtual machine,
              or have been attached to a virtual machine.
            </para>

            <para>
              Alternatively, click on the small
              <emphasis
                role="bold">folder
              icon</emphasis> next to the drop-down list to display a
              standard file dialog, where you can select any disk image
              file on your host disk.
            </para>
          </listitem>

        </itemizedlist>

        <para>
          If you are using VirtualBox for the first time, you will want
          to create a new disk image. Click the
          <emphasis role="bold">New</emphasis> button.
        </para>

        <para>
          This displays another window, the
          <emphasis
          role="bold">Create New Virtual Disk
          Wizard</emphasis>. This wizard helps you to create a new disk
          image file in the new virtual machine's folder.
        </para>

        <para>
          VirtualBox supports the following types of image files:
        </para>

        <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>
          For details about the differences, see
          <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"/>.
        </para>

        <mediaobject>
          <imageobject>
            <imagedata align="center" fileref="images/create-vdi-1.png"
                         width="10cm" />
          </imageobject>
        </mediaobject>

        <para>
          After having selected or created your image file, again click
          <emphasis role="bold">Next</emphasis> to go to the next page.
        </para>
      </listitem>

      <listitem>
        <para>
          After clicking on <emphasis role="bold">Finish</emphasis>
          button, your new virtual machine is created. The virtual
          machine is displayed in the list on the left side of the
          Manager window, with the name that you entered initially.
        </para>
      </listitem>

    </orderedlist>

    <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 the process of using
        wizards.
      </para>
    </note>

  </sect1>

  <sect1 id="intro-running">

    <title>Running Your Virtual Machine</title>

    <para>
      To start a virtual machine, you have several options:
    </para>

    <itemizedlist>

      <listitem>
        <para>
          Double-click on its entry in the list within the Manager
          window.
        </para>
      </listitem>

      <listitem>
        <para>
          Select its entry in the list in the Manager window, and click
          the <emphasis role="bold">Start</emphasis> button at the top.
        </para>
      </listitem>

      <listitem>
        <para>
          For virtual machines created with VirtualBox 4.0 or later,
          navigate to the <computeroutput>VirtualBox
          VMs</computeroutput> 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, which has
          a <computeroutput>.vbox</computeroutput> file extension.
        </para>
      </listitem>

    </itemizedlist>

    <para>
      Starting a virtual machine displays 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. See the screenshot image in
      <xref linkend="Introduction"/>.
    </para>

    <para>
      In general, you can use the virtual machine as you would use a
      real computer. There are couple of points worth mentioning
      however.
    </para>

    <sect2 id="intro-starting-vm-first-time">

      <title>Starting a New VM for the First Time</title>

      <para>
        When a VM is started for the first time, the
        <emphasis role="bold">First Start Wizard</emphasis>, is
        displayed. This wizard helps you to select an installation
        medium. 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 to 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, such as a Windows
            installation CD or DVD, put the media into your host's CD or
            DVD drive.
          </para>

          <para>
            In the wizard's drop-down list of installation media, select
            <emphasis role="bold">Host Drive</emphasis> with the correct
            drive letter. In the case of a Linux host, choose a 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 such as with a Linux
            distribution, you would normally burn this file to an empty
            CD or DVD and proceed as described above. 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>
            In 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, click the small folder
            icon next to the drop-down list to display a standard file
            dialog. Here you can pick an image file on your host disks.
          </para>
        </listitem>

      </itemizedlist>

      <para>
        After completing 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. 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
        <emphasis>captured</emphasis> as described below. See
        <xref linkend="settings-motherboard" />.
      </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. But 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>
        After installing a guest operating system and before you install
        the Guest Additions, described later, either your VM or the rest
        of your computer can "own" the keyboard and the mouse. Both
        cannot own the keyboard and mouse at the same time. You will see
        a <emphasis>second</emphasis> mouse pointer which is always
        confined to the limits of the VM window. 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: the
        <emphasis role="bold">Host key</emphasis>. By default, this is
        the <emphasis>right Ctrl 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" />. The current setting
        for the Host key is always displayed at the bottom right of your
        VM window.
      </para>

      <mediaobject>
        <imageobject>
          <imagedata align="center" fileref="images/vm-hostkey.png"
                       width="7cm" />
        </imageobject>
      </mediaobject>

      <para>
        This means the following:
      </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. If you have many windows open in your guest
            operating system, the window that has the focus in your VM
            is used. 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, this is typically the right Ctrl key.
          </para>

          <para>
            Note that while the VM owns the keyboard, some key
            sequences, such as Alt-Tab, will no longer be seen by the
            host, but will go to the guest instead. After you press the
            Host key to reenable the host keyboard, all key presses will
            go through the host again, so that sequences such as 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, press the Host
            key.
          </para>
        </listitem>

      </itemizedlist>

      <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 is described 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. Which 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>
            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 and restarts the entire
            graphical user interface. 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>
            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 you 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
                <emphasis role="bold">Input</emphasis>,
                <emphasis role="bold">Keyboard</emphasis> menu of the
                virtual machine window. This menu includes the settings
                <emphasis role="bold">Insert Ctrl+Alt+Delete</emphasis>
                and <emphasis role="bold">Ctrl+Alt+Backspace</emphasis>.
                The latter will only have an effect with Linux or
                Solaris guests, however.
              </para>
            </listitem>

            <listitem>
              <para>
                Use special key combinations with the Host key, normally
                the right Control key. VirtualBox will then translate
                these key combinations for the virtual machine:
              </para>

              <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 + Function
                    key</emphasis>. For example, to simulate Ctrl+Alt+Fx
                    to switch between virtual terminals in a Linux
                    guest.
                  </para>
                </listitem>

              </itemizedlist>
            </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".
          </para>
        </listitem>

      </itemizedlist>

    </sect2>

    <sect2 id="intro-removable-media-changing">

      <title>Changing Removable Media</title>

      <para>
        While a virtual machine is running, you can change removable
        media in the <emphasis role="bold">Devices</emphasis> 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, 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:
      </para>

      <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 <emphasis role="bold">Scale
            mode</emphasis> from the
            <emphasis role="bold">Machine</emphasis> 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>
            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>
            See <xref linkend="guestadditions" />.
          </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>

    </sect2>

    <sect2 id="intro-save-machine-state">

      <title>Saving the State of the Machine</title>

      <para>
        When you click on the <emphasis role="bold">Close</emphasis>
        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 Host key + Q.
      </para>

      <para>
        <mediaobject>
          <imageobject>
            <imagedata align="center" fileref="images/vm-close.png"
                       width="11cm" />
          </imageobject>
        </mediaobject>

        The difference between the three options is crucial. They mean
        the following:
      </para>

      <itemizedlist>

        <listitem>
          <para>
            <emphasis role="bold">Save the machine state:</emphasis>
            With this option, VirtualBox <emphasis>freezes</emphasis>
            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 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.
          </para>

          <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>
            As an exception, if your virtual machine has any snapshots,
            see <xref linkend="snapshots"/>, 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 the GUI. Do one of the following:
        </para>

        <itemizedlist>

          <listitem>
            <para>
              Drag one VM on top of another VM.
            </para>
          </listitem>

          <listitem>
            <para>
              Select multiple VMs and select
              <emphasis role="bold">Group</emphasis> from the
              right-click menu, as shown in the following image.
            </para>

            <para>
              <mediaobject>
                <imageobject>
                  <imagedata align="center" fileref="images/vm-groups.png"
                 width="10cm" />
                </imageobject>
              </mediaobject>
            </para>
          </listitem>

        </itemizedlist>
      </listitem>

      <listitem>
        <para>
          Create and manage a group using the command line. Do one of
          the following:
        </para>

        <itemizedlist>

          <listitem>
            <para>
              Create a group and assign a VM. For example:
            </para>

<screen>VBoxManage modifyvm "Fred" --groups "/TestGroup"</screen>

            <para>
              This command creates a group "TestGroup" and attaches the
              VM "Fred" to that group.
            </para>
          </listitem>

          <listitem>
            <para>
              Detach a VM from the group, and delete the group if empty.
              For example:
            </para>

<screen>VBoxManage modifyvm "Fred" --groups ""</screen>

            <para>
              This command detaches all groups from the VM "Fred" and
              deletes the empty group.
            </para>
          </listitem>

        </itemizedlist>
      </listitem>

      <listitem>
        <para>
          Create multiple groups. For example:
        </para>

<screen>VBoxManage modifyvm "Fred" --groups "/TestGroup,/TestGroup2"</screen>

        <para>
          This command creates the groups "TestGroup" and "TestGroup2",
          if they do not exist, and attaches the VM "Fred" to both of
          them.
        </para>
      </listitem>

      <listitem>
        <para>
          Create nested groups, having a group hierarchy. For example:
        </para>

<screen>VBoxManage modifyvm "Fred" --groups "/TestGroup/TestGroup2"</screen>

        <para>
          This command attaches the VM "Fred" to the subgroup
          "TestGroup2" of the "TestGroup" group.
        </para>
      </listitem>

      <listitem>
        <para>
          The following is a 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
      <emphasis role="bold">Snapshots</emphasis> button at the top
      right. Until you take a snapshot of the machine, the list of
      snapshots will be empty except for the
      <emphasis role="bold">Current State</emphasis> item, which
      represents the "now" point in the lifetime of the virtual machine.
    </para>

    <sect2 id="snapshots-take-restore-delete">

      <title>Taking, Restoring, and Deleting Snapshots</title>

      <para>
        There are three operations related to snapshots, as follows:
      </para>

      <orderedlist>

        <listitem>
          <para>
            <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.
          </para>

          <itemizedlist>

            <listitem>
              <para>
                If your VM is currently running, select
                <emphasis role="bold">Take Snapshot</emphasis> from the
                <emphasis role="bold">Machine</emphasis> 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
                <emphasis role="bold">Snapshots </emphasis>tab on the
                top right of the main window. Do one of the following:
              </para>

              <itemizedlist>

                <listitem>
                  <para>
                    Click on the small camera icon.
                  </para>
                </listitem>

                <listitem>
                  <para>
                    Right-click on the <emphasis role="bold">Current
                    State </emphasis>item in the list and select
                    <emphasis role="bold">Take Snapshot</emphasis> from
                    the menu.
                  </para>
                </listitem>

              </itemizedlist>
            </listitem>

          </itemizedlist>

          <para>
            In either case, a window is displayed prompting 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.
          </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.
          </para>

          <mediaobject>
            <imageobject>
              <imagedata align="center" fileref="images/snapshots-1.png"
                             width="12cm" />
            </imageobject>
          </mediaobject>

          <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
            <xref linkend="snapshots-contents"/> for details on what is
            stored in a snapshot.
          </para>
        </listitem>

        <listitem>
          <para>
            <emphasis role="bold">Restore a snapshot</emphasis>. You do
            this 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" />.
            </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>
            <emphasis role="bold">Delete a snapshot</emphasis>. This
            does not affect the state of the virtual machine, but only
            releases 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
            <emphasis role="bold">Delete</emphasis>. Snapshots can be
            deleted even while a machine is running.
          </para>

          <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>
            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>

    </sect2>

    <sect2 id="snapshots-contents">

      <title>Snapshot Contents</title>

      <para>
        Think of a snapshot as a point in time that you have preserved.
        More formally, a snapshot consists of the following three
        things:
      </para>

      <itemizedlist>

        <listitem>
          <para>
            The snapshot 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 and 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. 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, 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>
            If you took a snapshot while the machine was running, the
            memory state of the machine is also saved in the snapshot.
            This is in the same way that memory can be saved when you
            close a 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>

    </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 <emphasis role="bold">Settings</emphasis> 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 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 perform well when, for example, half
        of its memory is taken away. As a result, if the Settings button
        is disabled, shut down the current VM first.
      </para>
    </note>

    <para>
      VirtualBox provides a wide range 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 id="intro-removing">

    <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 and select
      <emphasis role="bold">Remove</emphasis>.
    </para>

    <para>
      A confirmation window is displayed 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>

        <para>
          Cloning support was introduced with VirtualBox 4.1.
        </para>

      </footnote>
    </para>

    <para>
      A wizard guides you through the clone process.
    </para>

    <mediaobject>
      <imageobject>
        <imagedata align="center" fileref="images/clone-vm.png"
                   width="10cm" />
      </imageobject>
    </mediaobject>

    <para>
      This wizard can be started from the right-click menu of the
      Manager's VM list, by clicking
      <emphasis role="bold">Clone</emphasis>, or the
      <emphasis role="bold">Snapshots</emphasis> 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 if a
      fully independent clone should be created.
    </para>

    <itemizedlist>

      <listitem>
        <para>
          <emphasis role="bold">Full clone:</emphasis> In this mode, all
          dependent 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 what exactly
      should be cloned. You can always create a clone of the
      <emphasis>current state</emphasis> only or
      <emphasis>all</emphasis>. When you select
      <emphasis>all</emphasis>, the current state and in addition all
      snapshots are cloned. If 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 snapshots.
    </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>
      To clone a VM from the command line, 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>virtual
      appliances</emphasis>. These are disk images, together with
      configuration settings that can be distributed easily. This way
      one can offer complete ready-to-use software packages, including
      operating systems with applications, that need no configuration or
      installation except for importing into VirtualBox.
    </para>

    <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, see
        <xref
        linkend="KnownIssues" />.
      </para>
    </note>

    <para>
      Appliances in OVF format can appear in the following variants:
    </para>

    <itemizedlist>

      <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" />. They also include 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>

    </itemizedlist>

    <para>
      To <emphasis role="bold">import an appliance</emphasis> in one of
      the above formats, double-click on the OVF/OVA file.

      <footnote>

        <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 <emphasis role="bold">File</emphasis>,
      <emphasis role="bold">Import Appliance</emphasis> from the Manager
      window. In the displayed file dialog, 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>

    <mediaobject>
      <imageobject>
        <imagedata align="center" fileref="images/ovf-import.png"
                     width="12cm" />
      </imageobject>
    </mediaobject>

    <para>
      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>
      To import an image using the command line, see
      <xref
    linkend="vboxmanage-import" />.
    </para>

    <para>
      To <emphasis role="bold">export virtual machines</emphasis> that
      you already have in VirtualBox, select
      <emphasis role="bold">File</emphasis>, <emphasis role="bold">
      Export Appliance</emphasis>. A dialog window is displayed that
      enables you to combine several virtual machines into an OVF
      appliance. Select the target location where the target files
      should be stored, and the conversion process begins. This can take
      a while.
    </para>

    <para>
      To export an image using the command line, see
      <xref
    linkend="vboxmanage-export" />.
    </para>

    <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. The disk images in the export will have a "flattened"
        state identical to the current state of the virtual machine.
      </para>
    </note>

  </sect1>

  <sect1 id="globalsettings">

    <title>Global Settings</title>

    <para>
      The Global Settings dialog can be displayed using the
      <emphasis role="bold">File</emphasis> menu, by clicking the
      <emphasis role="bold">Preferences</emphasis> item. This dialog
      offers a selection of settings, most of which apply to all virtual
      machines of the current user. The
      <emphasis role="bold">Extensions</emphasis> option applies to the
      entire system.
    </para>

    <para>
      The following settings are available:
    </para>

    <itemizedlist>

      <listitem>
        <para>
          <emphasis role="bold">General.</emphasis> Enables the user to
          specify the default folder/directory for VM files, and the
          VRDP Authentication Library.
        </para>
      </listitem>

      <listitem>
        <para>
          <emphasis role="bold">Input.</emphasis> Enables the user to
          specify the Host yey. 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>

    </itemizedlist>

  </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.
      For example, you can 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>
      The following front-ends are shipped in the standard VirtualBox
      package:
    </para>

    <itemizedlist>

      <listitem>
        <para>
          <computeroutput>VirtualBox</computeroutput> is the VirtualBox
          Manager. This graphical user interface uses the Qt toolkit,
          and is described throughout this User Manual. While this is
          the simplest and easiest front-end to use, some of the more
          advanced VirtualBox features are not included.
        </para>
      </listitem>

      <listitem>
        <para>
          <computeroutput>VBoxManage</computeroutput> is a command-line
          interface for automated and detailed control of every aspect
          of VirtualBox. See <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 can be used
          in environments where displaying all the features of the full
          GUI is not feasible. See <xref
          linkend="vboxsdl" />.
        </para>
      </listitem>

      <listitem>
        <para>
          <computeroutput>VBoxHeadless</computeroutput> is a front-end
          that produces no visible output on the host at all, but can
          act as a RDP server if the VirtualBox Remote Desktop Extension
          (VRDE) is installed and enabled for the VM. 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. See
          <xref
          linkend="vboxheadless" />.
        </para>
      </listitem>

    </itemizedlist>

    <para>
      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. See <xref linkend="VirtualBoxAPI" />.
    </para>

  </sect1>

</chapter>