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<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN"

"http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd">

<chapter>

<title id="Introduction">First steps</title>

<para>Welcome to $VBOX_PRODUCT!</para>

<para>VirtualBox is a cross-platform virtualization application. What does

that mean? For one thing, it installs on your existing Intel or AMD-based

computers, whether they are running Windows, Mac, Linux or Solaris operating

systems. Secondly, it extends the capabilities of your existing computer so

that it can run multiple operating systems (inside multiple virtual

machines) at the same time. So, for example, you can run Windows and Linux

on your Mac, run Windows Server 2008 on your Linux server, run Linux on your

Windows PC, and so on, all alongside your existing applications. You can

install and run as many virtual machines as you like -- the only practical

limits are disk space and memory.</para>

<para>VirtualBox is deceptively simple yet also very powerful. It can run

everywhere from small embedded systems or desktop class machines all the way

up to datacenter deployments and even Cloud environments.</para>

<para>The following screenshot shows you how VirtualBox, installed on a

Linux machine, is running Windows 7 in a virtual machine window:</para>

<para><mediaobject>

<imageobject>

<imagedata align="center" fileref="images/vm-vista-running.png"

width="10cm" />

</imageobject>

</mediaobject></para>

<para>In this User Manual, we'll begin simply with a quick introduction to

virtualization and how to get your first virtual machine running with the

easy-to-use VirtualBox graphical user interface. Subsequent chapters will go

into much more detail covering more powerful tools and features, but

fortunately, it is not necessary to read the entire User Manual before you

can use VirtualBox.</para>

<para>You can find a summary of VirtualBox's capabilities in <xref

linkend="features-overview" />. For existing VirtualBox users who just want

to see what's new in this release, there is a detailed list in <xref

linkend="ChangeLog" />.</para>

<sect1>

<title>Why is virtualization useful?</title>

<para>The techniques and features that VirtualBox provides are useful for

several scenarios:</para>

<itemizedlist>

<listitem>

<para><emphasis role="bold">Operating system support.</emphasis> With

VirtualBox, one can run software written for one operating system on

another (for example, Windows software on Linux or a Mac) without

having to reboot to use it. Since you can configure what kinds of

hardware should be presented to each virtual machine, you can even

install an old operating system such as DOS or OS/2 in a virtual

machine if your real computer's hardware is no longer supported by

that operating system.</para>

</listitem>

<listitem>

<para><emphasis role="bold">Testing and disaster recovery.</emphasis>

Once installed, a virtual machine and its virtual hard disks can be

considered a "container" that can be arbitrarily frozen, woken up,

copied, backed up, and transported between hosts.</para>

<para>On top of that, with the use of another VirtualBox feature

called "snapshots", one can save a particular state of a virtual

machine and revert back to that state, if necessary. This way, one can

freely experiment with a computing environment. If something goes

wrong (e.g. after installing misbehaving software or infecting the

guest with a virus), one can easily switch back to a previous snapshot

and avoid the need of frequent backups and restores.</para>

<para>Any number of snapshots can be created, allowing you to travel

back and forward in virtual machine time. You can delete snapshots

while a VM is running to reclaim disk space.</para>

</listitem>

<listitem>

<para><emphasis role="bold">Infrastructure consolidation.</emphasis>

Virtualization can significantly reduce hardware and electricity

costs. Servers today typically run with fairly low average system

loads and are rarely used to their full potential. A lot of hardware

potential 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>

<para>With VirtualBox, you can even run virtual machines as mere

servers for the VirtualBox Remote Desktop Protocol (VRDP), with full

client USB support. This allows for consolidating the desktop machines

in an enterprise on just a few RDP servers, while the actual clients

only have to be capable of displaying VRDP data.</para>

</listitem>

<listitem>

<para><emphasis role="bold">Easier software installations.</emphasis>

Virtual machines can be used by software vendors to ship entire

software configurations. For example, installing a complete mail

server solution on a real machine can be a tedious task. With

virtualization it becomes possible to ship an entire software

solution, possibly consisting of many different components, in a

virtual machine, which is then often called an "appliance". Installing

and running a mail server becomes as easy as importing such an

appliance into VirtualBox.</para>

</listitem>

</itemizedlist>

</sect1>

<sect1>

<title id="virtintro">Some terminology</title>

<para>When dealing with virtualization (and also for understanding the

following chapters of this documentation), it helps to acquaint oneself

with a bit of crucial terminology, especially the following terms:</para>

<glosslist>

<glossentry>

<glossterm>Host operating system (host OS):</glossterm>

<glossdef>

<para>the operating system of the physical computer on which

VirtualBox was installed. There are versions of VirtualBox for

Windows, Mac OS X, Linux and Solaris hosts; for details, please see

<xref linkend="hostossupport" />. While the various VirtualBox

versions are usually discussed together in this document, there may

be platform-specific differences which we will point out where

appropriate.</para>

</glossdef>

</glossentry>

<glossentry>

<glossterm>Guest operating system (guest OS):</glossterm>

<glossdef>

<para>the operating system that is running inside the virtual

machine. Theoretically, VirtualBox can run any x86 operating system

(DOS, Windows, OS/2, FreeBSD, OpenBSD), but to achieve near-native

performance of the guest code on your machine, we had to go through

a lot of optimizations that are specific to certain operating

systems. So while your favorite operating system

<emphasis>may</emphasis> run as a guest, we officially support and

optimize for a select few (which, however, include the most common

ones).</para>

<para>See <xref linkend="guestossupport" /> for details.</para>

</glossdef>

</glossentry>

<glossentry>

<glossterm>Virtual machine (VM).</glossterm>

<glossdef>

<para>When running, a VM is the special environment that VirtualBox

creates for your guest operating system. So, 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 by use of the VirtualBox Remote Desktop

Protocol (VRDP).</para>

<para>Sometimes we also use the term "virtual machine" in a more

abstract way. Internally, VirtualBox thinks of a VM as a set of

parameters that determine its behavior. They include hardware

settings (how much memory the VM should have, what hard disks

VirtualBox should virtualize through which container files, what CDs

are mounted etc.) as well as state information (whether the VM is

currently running, saved, its snapshots etc.).</para>

<para>These settings are mirrored in the VirtualBox graphical user

interface as well as the <computeroutput>VBoxManage</computeroutput>

command line program; see <xref linkend="vboxmanage" />. In other

words, a VM is also what you can see in its settings dialog.</para>

</glossdef>

</glossentry>

<glossentry>

<glossterm>Guest Additions.</glossterm>

<glossdef>

<para>With "Guest Additions", we refer to special software packages

that are shipped with VirtualBox. Even though they are part of

VirtualBox, they are designed to be installed

<emphasis>inside</emphasis> a VM to improve performance of the guest

OS and to add extra features. This is described in detail in <xref

linkend="guestadditions" />.</para>

</glossdef>

</glossentry>

</glosslist>

</sect1>

<sect1 id="features-overview">

<title>Features overview</title>

<para>Here's a brief outline of VirtualBox's main features:</para>

<itemizedlist>

<listitem>

<para><emphasis role="bold">Portability.</emphasis> VirtualBox runs on

a large number of 32-bit and 64-bit host operating systems (again, see

<xref linkend="hostossupport" /> for details).</para>

<para>VirtualBox is a so-called "hosted" hypervisor (sometimes

referred to as a "type 2" hypervisor). Whereas a "bare-metal" or "type

1" hypervisor would run directly on the hardware, VirtualBox requires

an existing operating system to be installed. It can thus run

alongside existing applications on that host.</para>

<para>To a very large degree, VirtualBox is functionally identical on

all of the host platforms, and the same file and image formats are

used. This allows you to run virtual machines created on one host on

another host with a different host operating system; for example, you

can create a virtual machine on Windows and then run it under

Linux.</para>

<para>In addition, virtual machines can easily be imported and

exported using the Open Virtualization Format (OVF, see <xref

linkend="ovf" />), an industry standard created for this purpose. You

can even import OVFs that were created with a different virtualization

software.</para>

</listitem>

<listitem>

<para><emphasis role="bold">No hardware virtualization

required.</emphasis> For many scenarios, VirtualBox does not require

the processor features built into newer hardware like Intel VT-x or

AMD-V. As opposed to many other virtualization solutions, you can

therefore use VirtualBox even on older hardware where these features

are not present. More details can be found in <xref

linkend="hwvirt" />.</para>

</listitem>

<listitem>

<para><emphasis role="bold">Guest Additions: shared folders, seamless

windows, 3D virtualization.</emphasis> The VirtualBox Guest Additions

are software packages which can be installed

<emphasis>inside</emphasis> of supported guest systems to improve

their performance and to provide additional integration and

communication with the host system. After installing the Guest

Additions, a virtual machine will support automatic adjustment of

video resolutions, seamless windows, accelerated 3D graphics and more.

The Guest Additions are described in detail in <xref

linkend="guestadditions" />.</para>

<para>In particular, Guest Additions provide for "shared folders",

which let you access files from the host system from within a guest

machine. Shared folders are described in <xref

linkend="sharedfolders" />.</para>

</listitem>

<listitem>

<para><emphasis role="bold">Great hardware support.</emphasis> Among

others, VirtualBox supports:</para>

<itemizedlist>

<listitem>

<para><emphasis role="bold">Guest multiprocessing

(SMP).</emphasis> VirtualBox can present up to 32 virtual CPUs to

a virtual machine, irrespective of how many CPU cores are actually

present in your host.</para>

</listitem>

<listitem>

<para><emphasis role="bold">USB 2.0 device support.</emphasis>

VirtualBox implements a virtual USB controller and allows you to

connect arbitrary USB devices to your virtual machines without

having to install device-specific drivers on the host. USB support

is not limited to certain device categories. For details, see

<xref linkend="settings-usb" />.</para>

</listitem>

<listitem>

<para><emphasis role="bold">Hardware compatibility.</emphasis>

VirtualBox virtualizes a vast array of virtual devices, among them

many devices that are typically provided by other virtualization

platforms. That includes IDE, SCSI and SATA hard disk controllers,

several virtual network cards and sound cards, virtual serial and

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 role="bold">ACPI power status support,</emphasis>

VirtualBox can even report to ACPI-aware guest operating systems

the power status of the host. For mobile systems running on

battery, the guest can thus enable energy saving and notify the

user of the remaining power (e.g. in fullscreen modes).</para>

</listitem>

<listitem>

<para><emphasis role="bold">Multiscreen resolutions.</emphasis>

VirtualBox virtual machines support screen resolutions many times

that of a physical screen, allowing them to be spread over a large

number of screens attached to the host system.</para>

</listitem>

<listitem>

<para><emphasis role="bold">Built-in iSCSI support.</emphasis>

This unique feature allows you to connect a virtual machine

directly to an iSCSI storage server without going through the host

system. The VM accesses the iSCSI target directly without the

extra overhead that is required for virtualizing hard disks in

container files. For details, see <xref

linkend="storage-iscsi" />.</para>

</listitem>

<listitem>

<para><emphasis role="bold">PXE Network boot.</emphasis> The

integrated virtual network cards of VirtualBox fully support

remote booting via the Preboot Execution Environment (PXE).</para>

</listitem>

</itemizedlist>

</listitem>

<listitem>

<para><emphasis role="bold">Multigeneration branched

snapshots.</emphasis> VirtualBox can save arbitrary snapshots of the

state of the virtual machine. You can go back in time and revert the

virtual machine to any such snapshot and start an alternative VM

configuration from there, effectively creating a whole snapshot tree.

For details, see <xref linkend="snapshots" />. You can delete

snapshots while the virtual machine is running.</para>

</listitem>

<listitem>

<para><emphasis role="bold">Clean architecture; unprecedented

modularity.</emphasis> VirtualBox has an extremely modular design with

well-defined internal programming interfaces and a clean separation of

client and server code. This makes it easy to control it from several

interfaces at once: for example, you can start a VM simply by clicking

on a button in the VirtualBox graphical user interface and then

control that machine from the command line, or even remotely. See

<xref linkend="frontends" /> for details.</para>

<para>Due to its modular architecture, VirtualBox can also expose its

full functionality and configurability through a comprehensive

<emphasis role="bold">software development kit (SDK),</emphasis> which

allows for integrating every aspect of VirtualBox with other software

systems. Please see <xref linkend="VirtualBoxAPI" /> for

details.</para>

</listitem>

<listitem>

<para><emphasis role="bold">Remote machine display.</emphasis> You can

run any virtual machine in a special VirtualBox program that acts as a

server for the VirtualBox Remote Desktop Protocol (VRDP), a

backward-compatible extension of the standard Remote Desktop Protocol.

With this unique feature, VirtualBox provides high-performance remote

access to any virtual machine.</para>

<para>VirtualBox's VRDP support does not rely on the RDP server that

is built into Microsoft Windows. Instead, a custom VRDP server has

been built directly into the virtualization layer. As a result, it

works with any operating system (even in text mode) and does not

require application support in the virtual machine either.</para>

<para>VRDP support is described in detail in <xref

linkend="vrdp" />.</para>

<para>On top of this special capacity, VirtualBox offers you more

unique features:<itemizedlist>

<listitem>

<para><emphasis role="bold">Extensible RDP

authentication.</emphasis> VirtualBox already supports Winlogon

on Windows and PAM on Linux for RDP authentication. In addition,

it includes an easy-to-use SDK which allows you to create

arbitrary interfaces for other methods of authentication; see

<xref linkend="vbox-authenticate-sdk" /> for details.</para>

</listitem>

<listitem>

<para><emphasis role="bold">USB over RDP.</emphasis> Via RDP

virtual channel support, VirtualBox also allows you to connect

arbitrary USB devices locally to a virtual machine which is

running remotely on a VirtualBox RDP server; see <xref

linkend="usb-over-rdp" /> for details.</para>

</listitem>

</itemizedlist></para>

</listitem>

</itemizedlist>

</sect1>

<sect1>

<title id="hostossupport">Supported host operating systems</title>

<para>Currently, VirtualBox runs on the following host operating

systems:</para>

<itemizedlist>

<listitem>

<para><emphasis role="bold">Windows</emphasis> hosts:<itemizedlist>

<listitem>

<para>Windows XP, all service packs (32-bit)</para>

</listitem>

<listitem>

<para>Windows Server 2003 (32-bit)</para>

</listitem>

<listitem>

<para>Windows Vista (32-bit and 64-bit<footnote>

<para>Support for 64-bit Windows was added with VirtualBox

1.5.</para>

</footnote>).</para>

</listitem>

<listitem>

<para>Windows Server 2008 (32-bit and 64-bit)</para>

</listitem>

<listitem>

<para>Windows 7 (32-bit and 64-bit)</para>

</listitem>

</itemizedlist></para>

</listitem>

<listitem>

<para><emphasis role="bold">Mac OS X</emphasis> hosts:<footnote>

<para>Preliminary Mac OS X support (beta stage) was added with

VirtualBox 1.4, full support with 1.6. Mac OS X 10.4 (Tiger)

support was removed with VirtualBox 3.1.</para>

</footnote></para>

<itemizedlist>

<listitem>

<para>10.5 (Leopard, 32-bit)</para>

</listitem>

<listitem>

<para>10.6 (Snow Leopard, 32-bit and 64-bit)</para>

</listitem>

</itemizedlist>

<para>Intel hardware is required; please see <xref

linkend="KnownIssues" /> also.</para>

</listitem>

<listitem>

<para><emphasis role="bold">Linux</emphasis> hosts (32-bit and

64-bit<footnote>

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

1.4.</para>

</footnote>). Among others, this includes:<itemizedlist>

<listitem>

<para>Ubuntu 6.06 ("Dapper Drake"), 6.10 ("Edgy Eft"), 7.04

("Feisty Fawn"), 7.10 ("Gutsy Gibbon"), 8.04 ("Hardy Heron"),

8.10 ("Intrepid Ibex"), 9.04 ("Jaunty Jackalope"), 9.10 ("Karmic

Koala"), 10.04 ("Lucid Lynx").</para>

</listitem>

<listitem>

<para>Debian GNU/Linux 3.1 ("sarge"), 4.0 ("etch") and 5.0

("lenny")</para>

</listitem>

<listitem>

<para>Oracle Enterprise Linux 4 and 5</para>

</listitem>

<listitem>

<para>Redhat Enterprise Linux 4 and 5</para>

</listitem>

<listitem>

<para>Fedora Core 4 to 12</para>

</listitem>

<listitem>

<para>Gentoo Linux</para>

</listitem>

<listitem>

<para>SUSE Linux 9 and 10, openSUSE 10.3, 11.0, 11.1,

11.2</para>

</listitem>

<listitem>

<para>Mandriva 2007.1, 2008.0, 2009.1, 2010.0</para>

</listitem>

</itemizedlist></para>

<para>It should be possible to use VirtualBox on most systems based on

Linux kernel 2.6 using either the VirtualBox installer or by doing a

manual installation; see <xref linkend="install-linux-host" />.</para>

<para>Note that starting with VirtualBox 2.1, Linux 2.4-based host

operating systems are no longer supported.</para>

</listitem>

<listitem>

<para><emphasis role="bold">Solaris</emphasis> hosts (32-bit and

64-bit<footnote>

<para>Support for OpenSolaris was added with VirtualBox

1.6.</para>

</footnote>) are supported with the restrictions listed in <xref

linkend="KnownIssues" />:<itemizedlist>

<listitem>

<para>OpenSolaris (2008.05 and higher, "Nevada" build 86 and

higher)</para>

</listitem>

<listitem>

<para>Solaris 10 (u5 and higher)</para>

</listitem>

</itemizedlist></para>

</listitem>

</itemizedlist>

</sect1>

<sect1>

<title>Installing and starting VirtualBox</title>

<para>VirtualBox comes in many different packages, and <emphasis

role="bold">installation</emphasis> depends on your host platform. If you

have installed software before, installation should be straightforward as

on each host platform, VirtualBox uses the installation method that is

most common and easy to use. If you run into trouble or have special

requirements, please refer to <xref linkend="installation" /> for details

about the various installation methods.</para>

<para>After installation, you can start VirtualBox as

follows:<itemizedlist>

<listitem>

<para>On a Windows host, in the standard "Programs" menu, click on

the item in the "VirtualBox" group. On Vista or Windows 7, you can

also type "VirtualBox" in the search box of the "Start" menu.</para>

</listitem>

<listitem>

<para>On a Mac OS X host, in the Finder, double-click on the

"VirtualBox" item in the "Applications" folder. (You may want to

drag this item onto your Dock.)</para>

</listitem>

<listitem>

<para>On a Linux or Solaris host, depending on your desktop

environment, a "VirtualBox" item may have been placed in either the

"System" or "System Tools" group of your "Applications" menu.

Alternatively, you can type

<computeroutput>VirtualBox</computeroutput> in a terminal.</para>

</listitem>

</itemizedlist></para>

<para>When you start VirtualBox for the first time, a window like the

following should come up:</para>

<para><mediaobject>

<imageobject>

<imagedata align="center" fileref="images/virtualbox-main-empty.png"

width="10cm" />

</imageobject>

</mediaobject>On the left, you can see a pane that will later list all

your virtual machines. Since you have not created any, the list is empty.

A row of buttons above it allows you to create new VMs and work on

existing VMs, once you have some. The pane on the right displays the

properties of the virtual machine currently selected, if any. Again, since

you don't have any machines yet, the pane displays a welcome

message.</para>

<para>To give you an idea what VirtualBox might look like later, after you

have created many machines, here's another example:</para>

<para><mediaobject>

<imageobject>

<imagedata align="center" fileref="images/virtualbox-main.png"

width="10cm" />

</imageobject>

</mediaobject></para>

</sect1>

<sect1 id="gui-createvm">

<title>Creating your first virtual machine</title>

<para>Click on the "New" button at the top of the VirtualBox 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:<orderedlist>

<listitem>

<para>A <emphasis role="bold">name</emphasis> for your VM, and the

<emphasis role="bold">type of operating system</emphasis> (OS) you

want to install.</para>

<para>The name is what you will later see in the VirtualBox main

window, and what your settings will be stored under. It is purely

informational, but once you have created a few VMs, you will

appreciate if you have given your VMs informative names. "My VM"

probably is therefore not as useful as "Windows XP SP2".</para>

<para>For "Operating System Type", select the operating system that

you want to install later. 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>The <emphasis role="bold">amount of memory (RAM)</emphasis>

that the virtual machine should have for itself. Every time a

virtual machine is started, VirtualBox will allocate this much

memory from your host machine and present it to the guest operating

system, which will report this size as the (virtual) computer's

installed RAM.</para>

<para><note>

<para>Choose this setting carefully! The memory you give to the

VM will not be available to your host OS while the VM is

running, so do not specify more than you can spare. For example,

if your host machine has 1 GB of RAM and you enter 512 MB as the

amount of RAM for a particular virtual machine, while that VM is

running, you will only have 512 MB left for all the other

software on your host. If you run two VMs at the same time, even

more memory will be allocated for the second VM (which may not

even be able to start if that memory is not available). On the

other hand, you should specify as much as your guest OS (and

your applications) will require to run properly.</para>

</note></para>

<para>A Windows XP guest will require at least a few hundred MB RAM

to run properly, and Windows Vista will even refuse to install with

less than 512 MB. Of course, if you want to run graphics-intensive

applications in your VM, you may require even more RAM.</para>

<para>So, as a rule of thumb, if you have 1 GB of RAM or more in

your host computer, it is usually safe to allocate 512 MB to each

VM. But, in any case, make sure you always have at least 256 to 512

MB of RAM left on your host operating system. Otherwise you may

cause your host OS to excessively swap out memory to your hard disk,

effectively bringing your host system to a standstill.</para>

<para><note>

<para>VirtualBox restricts the amount of guest RAM to 1500 MB on

32-bit Windows hosts and to 2560 MB on 32-bit Linux and Solaris

hosts due to address-space limitations. These restrictions do

not apply to 64-bit hosts.</para>

</note></para>

<para>As with the other settings, you can change this setting later,

after you have created the VM.</para>

</listitem>

<listitem>

<para>Next, you must specify a <emphasis role="bold">virtual hard

disk</emphasis> for your VM.</para>

<para>There are many and potentially complicated ways in which

VirtualBox can provide hard disk space to a VM (see <xref

linkend="storage" /> for details), but the most common way is to use

a large image file on your "real" hard disk, whose contents

VirtualBox presents to your VM as if it were a complete hard

disk.</para>

<para>The wizard shows you the following window:</para>

<para><mediaobject>

<imageobject>

<imagedata align="center" fileref="images/create-vm-2.png"

width="10cm" />

</imageobject>

</mediaobject></para>

<para>The wizard allows you to create an image file or use an

existing one. Note also that the disk images can be separated from a

particular VM, so even if you delete a VM, you can keep the image,

or copy it to another host and create a new VM for it there.</para>

<para>In the wizard, you have the following options:</para>

<para><itemizedlist>

<listitem>

<para>If you have previously created any virtual hard disks

which have not been attached to other virtual machines, you

can select those from the drop-down list in the wizard

window.</para>

</listitem>

<listitem>

<para>Otherwise, to create a new virtual hard disk, press the

<emphasis role="bold">"New"</emphasis> button.</para>

</listitem>

<listitem>

<para>Finally, for more complicated operations with virtual

disks, the <emphasis role="bold">"Existing..."</emphasis>

button will bring up the Virtual Media Manager, which is

described in more detail in <xref linkend="vdis" />.</para>

</listitem>

</itemizedlist>Most probably, if you are using VirtualBox for the

first time, you will want to create a new disk image. Hence, press

the "New" button.</para>

<para>This brings up another window, the <emphasis

role="bold">"Create New Virtual Disk Wizard".</emphasis></para>

<para>VirtualBox supports two types of image files:<itemizedlist>

<listitem>

<para>A <emphasis role="bold">dynamically expanding

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

expanding file.</para>

</listitem>

</itemizedlist></para>

<para>For details about the differences, please refer to <xref

linkend="vdidetails" />.</para>

<para>To prevent your physical hard disk from running full,

VirtualBox limits the size of the image file. Still, it needs to be

large enough to hold the contents of your operating system and the

applications you want to install -- for a modern Windows or Linux

guest, you will probably need several gigabytes for any serious

use:</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 press

<emphasis role="bold">"Next"</emphasis> to go to the next

page.</para>

</listitem>

<listitem>

<para>After clicking on <emphasis role="bold">"Finish"</emphasis>,

your new virtual machine will be created. You will then see it in

the list on the left side of the main window, with the name you have

entered.</para>

</listitem>

</orderedlist></para>

</sect1>

<sect1>

<title>Running your virtual machine</title>

<para>You will now see your new virtual machine in the list of virtual

machines, at the left of the VirtualBox main window. To start the virtual

machine, simply double-click on it, or select it and press the "Start"

button at the top.</para>

<para>This opens up a new window, and the virtual machine which you

selected will boot up. Everything which would normally be seen on the

virtual system's monitor is shown in the window, as can be seen with the

image in <xref linkend="virtintro" />.</para>

<para>Since this is the first time you are running this VM, another wizard

will show up to help you 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 it cannot boot an operating system.</para>

<para>For this reason, the "First Start Wizard" helps you select an

operating system medium to install an operating system from. In most

cases, this will either be a real CD or DVD (VirtualBox can then configure

the virtual machine to use your host's drive), or you might have an ISO

image of a CD or DVD handy, which VirtualBox can then present to the

virtual machine.</para>

<para>In both cases, after making the choices in the wizard, you will be

able to install your operating system.</para>

<para>In general, you can use the virtual machine much like you would use

a real computer. There are couple of points worth mentioning

however.</para>

<sect2>

<title>Keyboard and mouse support in virtual machines</title>

<sect3>

<title id="keyb_mouse_normal">Capturing and releasing keyboard and

mouse</title>

<para>As of version 3.2, VirtualBox provides a virtual USB tablet

device to new virtual machines through which mouse events are

communicated to the guest operating system. As a result, if you are

running a fairly recent guest operating system that can handle such

devices, mouse support may work out of the box without the mouse being

"captured" as described below; see <xref

linkend="settings-motherboard" /> for more information.</para>

<para>Otherwise, if the virtual machine only sees standard PS/2 mouse

and keyboard devices, since the operating system in the virtual

machine does not "know" that it is not running on a real computer, it

expects to have exclusive control over your keyboard and mouse. This

is, however, not the case since, unless you are running the VM in

full-screen mode, your VM needs to share keyboard and mouse with other

applications and possibly other VMs on your host.</para>

<para>As a result, initially after installing a guest operating system

and before you install the Guest Additions (we will explain this in a

minute), only one of the two -- your VM or the rest of your computer

-- can "own" the keyboard and the mouse. You will see a

<emphasis>second</emphasis> mouse pointer which will always be

confined to the limits of the VM window. Basically, you activate the

VM by clicking inside it.</para>

<para>To return ownership of keyboard and mouse to your host operating

system, VirtualBox reserves a special key on your keyboard for itself:

the <emphasis role="bold">"host key".</emphasis> By default, this is

the <emphasis>right Control key</emphasis> on your keyboard; on a Mac

host, the default host key is the left Command key. You can change

this default in the VirtualBox Global Settings. In any case, the

current setting for the host key is always displayed <emphasis>at the

bottom right of your VM window,</emphasis> should you have forgotten

about it:</para>

<para><mediaobject>

<imageobject>

<imagedata align="center" fileref="images/vm-hostkey.png"

width="7cm" />

</imageobject>

</mediaobject>In detail, all this translates into the

following:</para>

<para><itemizedlist>

<listitem>

<para>Your <emphasis role="bold">keyboard</emphasis> is owned by

the VM if the VM window on your host desktop has the keyboard

focus (and then, if you have many windows open in your guest

operating system as well, the window that has the focus in your

VM). This means that if you want to type within your VM, click

on the title bar of your VM window first.</para>

<para>To release keyboard ownership, press the Host key (as

explained above, typically the right Control key).</para>

<para>Note that while the VM owns the keyboard, some key

sequences (like Alt-Tab for example) will no longer be seen by

the host, but will go to the guest instead. After you press the

host key to re-enable the host keyboard, all key presses will go

through the host again, so that sequences like Alt-Tab will no

longer reach the guest.</para>

</listitem>

<listitem>

<para>Your <emphasis role="bold">mouse</emphasis> is owned by

the VM only after you have clicked in the VM window. The host

mouse pointer will disappear, and your mouse will drive the

guest's pointer instead of your normal mouse pointer.</para>

<para>Note that mouse ownership is independent of that of the

keyboard: even after you have clicked on a titlebar to be able

to type into the VM window, your mouse is not necessarily owned

by the VM yet.</para>

<para>To release ownership of your mouse by the VM, also press

the Host key.</para>

</listitem>

</itemizedlist></para>

<para>As this behavior can be inconvenient, VirtualBox provides a set

of tools and device drivers for guest systems called the "VirtualBox

Guest Additions" which make VM keyboard and mouse operation a lot more

seamless. Most importantly, the Additions will get rid of the second

"guest" mouse pointer and make your host mouse pointer work directly

in the guest.</para>

<para>This will be described later in <xref

linkend="guestadditions" />.</para>

</sect3>

<sect3>

<title>Typing special characters</title>

<para>Operating systems expect certain key combinations to initiate

certain procedures. Some of these key combinations may be difficult to

enter into a virtual machine, as there are three candidates as to who

receives keyboard input: the host operating system, VirtualBox, or the

guest operating system. Who of these three receives keypresses depends

on a number of factors, including the key itself.</para>

<itemizedlist>

<listitem>

<para>Host operating systems reserve certain key combinations for

themselves. For example, it is impossible to enter the <emphasis

role="bold">Ctrl+Alt+Delete</emphasis> combination if you want to

reboot the guest operating system in your virtual machine, because

this key combination is usually hard-wired into the host OS (both

Windows and Linux intercept this), and pressing this key

combination will therefore reboot your

<emphasis>host</emphasis>.</para>

<para>Also, on Linux and Solairs hosts, which use the X Window

System, the key combination <emphasis

role="bold">Ctrl+Alt+Backspace</emphasis> normally resets the X

server (to restart the entire graphical user interface in case it

got stuck). As the X server intercepts this combination, pressing

it will usually restart your <emphasis>host</emphasis> graphical

user interface (and kill all running programs, including

VirtualBox, in the process).</para>

<para>Third, on Linux hosts supporting virtual terminals, the key

combination <emphasis role="bold">Ctrl+Alt+Fx</emphasis> (where Fx

is one of the function keys from F1 to F12) normally allows to

switch between virtual terminals. As with Ctrl+Alt+Delete, these

combinations are intercepted by the host operating system and

therefore always switch terminals on the

<emphasis>host</emphasis>.</para>

<para>If, instead, you want to send these key combinations to the

<emphasis>guest</emphasis> operating system in the virtual

machine, you will need to use one of the following methods:</para>

<itemizedlist>

<listitem>

<para>Use the items in the "Machine" menu of the virtual

machine window. There you will find "Insert Ctrl+Alt+Delete"

and "Ctrl+Alt+Backspace"; the latter will only have an effect

with Linux or Solaris guests, however.</para>

</listitem>

<listitem>

<para>Press special key combinations with the Host key

(normally the right Control key), which VirtualBox will then

translate for the virtual machine:<itemizedlist>

<listitem>

<para><emphasis role="bold">Host key + Del</emphasis> to

send Ctrl+Alt+Del (to reboot the guest);</para>

</listitem>

<listitem>

<para><emphasis role="bold">Host key +

Backspace</emphasis> to send Ctrl+Alt+Backspace (to

restart the graphical user interface of a Linux or

Solaris guest);</para>

</listitem>

<listitem>

<para><emphasis role="bold">Host key + F1</emphasis> (or

other function keys) to simulate Ctrl+Alt+F1 (or other

function keys, i.e. to switch between virtual terminals

in a Linux guest).</para>

</listitem>

</itemizedlist></para>

</listitem>

</itemizedlist>

</listitem>

<listitem>

<para>For some other keyboard combinations such as <emphasis

role="bold">Alt-Tab</emphasis> (to switch between open windows),

VirtualBox allows you to configure whether these combinations will

affect the host or the guest, if a virtual machine currently has

the focus. This is a global setting for all virtual machines and

can be found under "File" -&gt; "Preferences" -&gt; "Input" -&gt;

"Auto-capture keyboard".</para>

</listitem>

</itemizedlist>

</sect3>

</sect2>

<sect2>

<title>Changing removable media</title>

<para>While a virtual machine is running, you can change removable media

in the "Devices" menu of the VM's window. Here you can select in detail

what VirtualBox presents to your VM as a CD, DVD, or floppy.</para>

<para>The settings are the same as would be available for the VM in the

"Settings" dialog of the VirtualBox main window, but since that dialog

is disabled while the VM is in the "running" or "saved" state, this

extra menu saves you from having to shut down and restart the VM every

time you want to change media.</para>

<para>Hence, in the "Devices" menu, VirtualBox allows you to attach the

host drive to the guest or select a floppy or DVD image using the Disk

Image Manager, all as described in <xref

linkend="configbasics" />.</para>

</sect2>

<sect2>

<title>Saving the state of the machine</title>

<para>When you click on the "Close" button of your virtual machine

window (at the top right of the window, just like you would close any

other window on your system) (or press the Host key together with "Q"),

VirtualBox asks you whether you want to "save" or "power off" the

VM.</para>

<para><mediaobject>

<imageobject>

<imagedata align="center" fileref="images/vm-close.png"

width="7cm" />

</imageobject>

</mediaobject>The difference between these three options is crucial.

They mean:</para>

<itemizedlist>

<listitem>

<para><emphasis role="bold">Save the machine state:</emphasis> With

this option, VirtualBox "freezes" the virtual machine by completely

saving its state to your local disk. When you later resume the VM

(by again clicking the "Start" button in the VirtualBox main

window), 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.</para>

<para>Saving the state of a virtual machine is thus in some ways

similar to suspending a laptop computer (e.g. by closing its

lid).</para>

</listitem>

<listitem>

<para><emphasis role="bold">Send the shutdown signal.</emphasis>

This will send an ACPI shutdown signal to the virtual machine, which

has the same effect as if you had pressed the power button on a real

computer. So long as a fairly modern operating system is installed

and running in the VM, this should trigger a proper shutdown

mechanism in 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>

<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.</para>

<para>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>

<para>As an exception, if your virtual machine has any snapshots

(see the next chapter), you can use this option to quickly <emphasis

role="bold">restore the current snapshot</emphasis> of the virtual

machine. Only in that case, powering off the machine is not

harmful.</para>

</listitem>

</itemizedlist>

<para>The <emphasis role="bold">"Discard"</emphasis> button in the main

VirtualBox 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="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.</para>

<para>You can see the snapshots of a virtual machine by first selecting a

machine from the list on the left of the VirtualBox main window and then

selecting the "Snapshots" tab on the right. Initially, until you take a

snapshot of the machine, that list is empty except for the "Current state"

item, which represents the "Now" point in the lifetime of the virtual

machine.</para>

<para>There are three operations related to snapshots:<orderedlist>

<listitem>

<para>You can <emphasis role="bold">take a

snapshot</emphasis>.<itemizedlist>

<listitem>

<para>If your VM is currently running, select "Take snapshot"

from the "Machine" pull-down menu of the VM window.</para>

</listitem>

<listitem>

<para>If your VM is currently in either the "saved" or the

"powered off" state (as displayed next to the VM in the

VirtualBox main window), click on the "Snapshots" tab on the

top right of the main window, and then<itemizedlist>

<listitem>

<para>either on the small camera icon (for "Take

snapshot") or</para>

</listitem>

<listitem>

<para>right-click on the "Current State" item in the

list and select "Take snapshot" from the menu.</para>

</listitem>

</itemizedlist></para>

</listitem>

</itemizedlist></para>

<para>In any case, a window will pop up and ask you for a snapshot

name. This name is purely for reference purposes to help you

remember the state of the snapshot. For example, a useful name would

be "Fresh installation from scratch, no external drivers". You can

also add a longer text in the "Description" field if you

want.</para>

<para>Your new snapshot will then appear in the list of snapshots

under the "Snapshots" tab. Underneath, 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 a derivation of the

earlier one:<mediaobject>

<imageobject>

<imagedata align="center" fileref="images/snapshots-1.png"

width="10cm" />

</imageobject>

</mediaobject></para>

<para>VirtualBox allows you to take an unlimited number of snapshots

-- the only limitation is the size of your disks. Keep in mind that

each snapshot stores the state of the virtual machine and thus takes

some disk space.</para>

</listitem>

<listitem>

<para>You can <emphasis role="bold">restore a snapshot</emphasis> by

right-clicking on any snapshot you have taken in the list of

snapshots. By restoring a snapshot, you go back (or forward) in

time: the current state of the machine is lost, and the machine is

restored to exactly the same state as it was when then snapshot was

taken.<footnote>

<para>Both the terminology and the functionality of restoring

snapshots has changed with VirtualBox 3.1. Before that version,

it was only possible to go back to the very last snapshot taken

-- not earlier ones, and the operation was called "Discard

current state" instead of "Restore last snapshot". The

limitation has been lifted with version 3.1. It is now possible

to restore <emphasis>any</emphasis> snapshot, going backward and

forward in time.</para>

</footnote></para>

<note>

<para>Restoring a snapshot will affect the virtual hard drives

that are connected to your VM, as the entire state of the virtual

hard drive will be reverted as well. This means also that all

files that have been created since the snapshot and all other file

changes <emphasis>will be lost. </emphasis>In order to prevent

such data loss while still making use of the snapshot feature, it

is possible to add a second hard drive in "write-through" mode

using the <computeroutput>VBoxManage</computeroutput> interface

and use it to store your data. As write-through hard drives are

<emphasis>not</emphasis> included in snapshots, they remain

unaltered when a machine is reverted. See <xref

linkend="hdimagewrites" os="" /> for details.</para>

</note>

<para>By restoring an earlier snapshot and taking more snapshots

from there, it is even possible to create a kind of alternate

reality and to switch between these different histories of the

virtual machine. This can result in a whole tree of virtual machine

snapshots, as shown in the screenshot above.</para>

</listitem>

<listitem>

<para>You can also <emphasis role="bold">delete a

snapshot</emphasis>, which will not affect the state of the virtual

machine, but only release the files on disk that VirtualBox used to

store the snapshot data, thus freeing disk space. To delete a

snapshot, right-click on it in the snapshots tree and select

"Delete". As of VirtualBox 3.2, snapshots can be deleted even while

a machine is running.<note>

<para>Whereas taking and restoring snapshots are fairly quick

operations, deleting a snapshot can take a considerable amount

of time since large amounts of data may need to be copied

between several disk image files. Temporary disk files may also

need large amounts of disk space while the operation is in

progress.</para>

</note></para>

<para>There are some situations which cannot be handled while a VM

is running, and you will get an appropriate message that you need to

perform this snapshot deletion when the VM is shut down.</para>

</listitem>

</orderedlist></para>

<para>Think of a snapshot as a point in time that you have preserved. More

formally, a snapshot consists of three things:<itemizedlist>

<listitem>

<para>It contains a complete copy of the VM settings, so that when

you restore a snapshot, the VM settings are restored as well. (For

example, if you changed the hard disk configuration, that change is

undone when you restore the snapshot.)</para>

</listitem>

<listitem>

<para>The state of all the virtual disks attached to the machine is

preserved. Going back to a snapshot means that all changes, bit by

bit, that had been made to the machine's disks will be undone as

well.</para>

<para>(Strictly speaking, this is only true for virtual hard disks

in "normal" mode. As mentioned above, you can configure disks to

behave differently with snapshots; see <xref

linkend="hdimagewrites" />. Even more formally and technically

correct, it is not the virtual disk itself that is restored when a

snapshot is restored. Instead, when a snapshot is taken, VirtualBox

creates differencing images which contain only the changes since the

snapshot were taken, and when the snapshot is restored, VirtualBox

throws away that differencing image, thus going back to the previous

state. This is both faster and uses less disk space. For the

details, which can be complex, please see <xref

linkend="diffimages" />.)</para>

</listitem>

<listitem>

<para>Finally, if you took a snapshot while the machine was running,

the memory state of the machine is also saved in the snapshot (the

same way the memory can be saved when you close the VM window) so

that when you restore the snapshot, execution resumes at exactly the

point when the snapshot was taken.</para>

</listitem>

</itemizedlist></para>

</sect1>

<sect1>

<title id="configbasics">Virtual machine configuration</title>

<para>When you select a virtual machine from the list in the main

VirtualBox window, you will see a summary of that machine's settings on

the right of the window, under the "Details" tab.</para>

<para>Clicking on the "Settings" button in the toolbar at the top of

VirtualBox main window brings up a detailed window where you can configure

many of the properties of the VM that is currently selected. But be

careful: even though it is possible to change all VM settings after

installing a guest operating system, certain changes might prevent a guest

operating system from functioning correctly if done after

installation.</para>

<note>

<para>The "Settings" button is disabled while a VM is either in the

"running" or "saved" state. This is simply because the settings dialog

allows you to change fundamental characteristics of the virtual computer

that is created for your guest operating system, and this operating

system may not take it well when, for example, half of its memory is

taken away from under its feet. As a result, if the "Settings" button is

disabled, shut down the current VM first.</para>

</note>

<para>VirtualBox provides a plethora of parameters that can be changed for

a virtual machine. The various settings that can be changed in the

"Settings" window are described in detail in <xref

linkend="BasicConcepts" />. Even more parameters are available with the

command line interface; see <xref linkend="vboxmanage" />.</para>

<para>For now, if you have just created an empty VM, you will probably be

most interested in the settings presented by the "CD/DVD-ROM" section if

you want to make a CD or a DVD available the first time you start it, in

order to install your guest operating system.</para>

<para>For this, you have two options:</para>

<itemizedlist>

<listitem>

<para>If you have actual CD or DVD media from which you want to

install your guest operating system (e.g. in the case of a Windows

installation CD or DVD), put the media into your host's CD or DVD

drive.</para>

<para>Then, in the settings dialog, go to the "CD/DVD-ROM" section and

select "Host drive" with the correct drive letter (or, in the case of

a Linux host, device file).</para>

<para>This will allow your VM to access the media in your host drive,

and you can proceed to install from there.</para>

</listitem>

<listitem>

<para>If you have downloaded installation media from the Internet in

the form of an ISO image file (most probably in the case of a Linux

distribution), you would normally burn this file to an empty CD or DVD

and proceed as just described. With VirtualBox however, you can skip

this step and mount the ISO file directly. VirtualBox will then

present this file as a CD or DVD-ROM drive to the virtual machine,

much like it does with virtual hard disk images.</para>

<para>In this case, in the settings dialog, go to the "CD/DVD-ROM"

section and select "ISO image file". This brings up the Virtual Media

Manager, where you perform the following steps:</para>

<para><orderedlist>

<listitem>

<para>Press the "Add" button to add your ISO file to the list of

registered images. This will present an ordinary file dialog

that allows you to find your ISO file on your host

machine.</para>

</listitem>

<listitem>

<para>Back to the manager window, select the ISO file that you

just added and press the "Select" button. This selects the ISO

file for your VM.</para>

</listitem>

</orderedlist></para>

<para>The Virtual Media Manager is described in detail in <xref

linkend="vdis" />.</para>

</listitem>

</itemizedlist>

</sect1>

<sect1>

<title>Deleting virtual machines</title>

<para>To remove a virtual machine which you no longer need, right-click on

it in the list of virtual machines in the main window and select "Delete"

from the context menu that comes up. All settings for that machine will be

lost.</para>

<para>The "Delete" menu item is disabled while a machine is in "Saved"

state. To delete such a machine, discard the saved state first by pressing

on the "Discard" button.</para>

<para>However, any hard disk images attached to the machine will be kept;

you can delete those separately using the Virtual Media Manager; see <xref

linkend="vdis" />.</para>

<para>You cannot delete a machine which has snapshots or is in a saved

state, so you must discard these first.</para>

</sect1>

<sect1 id="ovf">

<title>Importing and exporting virtual machines</title>

<para>Starting with version 2.2, VirtualBox can import and export virtual

machines in the industry-standard Open Virtualization Format (OVF).</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. As opposed to

other virtualization products, VirtualBox now supports OVF with an

easy-to-use graphical user interface as well as using the command line.

This allows for packaging so-called <emphasis role="bold">virtual

appliances</emphasis>: disk images together with configuration settings

that can be distributed easily. This way one can offer complete

ready-to-use software packages (operating systems with applications) that

need no configuration or installation except for importing into

VirtualBox.<note>

<para>The OVF standard is complex, and support in VirtualBox is an

ongoing process. In particular, no guarantee is made that VirtualBox

supports all appliances created by other virtualization software. For

a list of know limitations, please see <xref

linkend="KnownIssues" />.</para>

</note></para>

<para>An appliance in OVF format will typically consist of several

files:<orderedlist>

<listitem>

<para>one or several disk images, typically in the widely-used VMDK

format (see <xref linkend="vdidetails" />) and</para>

</listitem>

<listitem>

<para>a textual description file in an XML dialect with an

<computeroutput>.ovf</computeroutput> extension.</para>

</listitem>

</orderedlist></para>

<para>These files must reside in the same directory for VirtualBox to be

able to import them.</para>

<para>A future version of VirtualBox will also support packages that

include the OVF XML file and the disk images packed together in a single

archive.</para>

<para>To <emphasis role="bold">import</emphasis> an appliance in OVF

format, select "File" -&gt; "Import appliance" from the main window of the

VirtualBox graphical user interface. Then open the file dialog and

navigate to the OVF text file with the

<computeroutput>.ovf</computeroutput> file extension.</para>

<para>If VirtualBox can handle the file, a dialog similar to the following

will appear:</para>

<para><mediaobject>

<imageobject>

<imagedata align="center" fileref="images/ovf-import.png"

width="10cm" />

</imageobject>

</mediaobject>This presents the virtual machines described in the OVF

file and allows you to change the virtual machine settings by

double-clicking on the description items. Once you click on <emphasis

role="bold">"Import"</emphasis>, VirtualBox will copy the disk images and

create local virtual machines with the settings described in the dialog.

These will then show up in the list of virtual machines.</para>

<para>Note that since disk images tend to be big, and VMDK images that

come with virtual appliances are typically shipped in a special compressed

format that is unsuitable for being used by virtual machines directly, the

images will need to be unpacked and copied first, which can take a few

minutes.</para>

<para>For how to import an image at the command line, please see <xref

linkend="vboxmanage-import" />.</para>

<para>Conversely, to <emphasis role="bold">export</emphasis> virtual

machines that you already have in VirtualBox, select the machines and

"File" -&gt; "Export appliance". A different dialog window shows up that

allows you to combine several virtual machines into an OVF appliance.

Then, you select the target location where the OVF and VMDK files should

be stored, and the conversion process begins. This can again take a

while.</para>

<para>For how to export an image at the command line, please see <xref

linkend="vboxmanage-export" />.<note>

<para>OVF cannot describe snapshots that were taken for a virtual

machine. As a result, when you export a virtual machine that has

snapshots, only the current state of the machine will be exported, and

the disk images in the export will have a "flattened" state identical

to the current state of the virtual machine.</para>

</note></para>

</sect1>

<sect1 id="frontends">

<title>Alternative front-ends</title>

<para>As briefly mentioned in <xref linkend="features-overview" />,

VirtualBox has a very flexible internal design that allows you to use

different front-ends to control the same virtual machines. To illustrate,

you can, for example, start a virtual machine with VirtualBox's

easy-to-use graphical user interface and then stop it from the command

line. With VirtualBox's support for the Remote Desktop Protocol (VRDP),

you can even run virtual machines remotely on a headless server and have

all the graphical output redirected over the network.</para>

<para>In detail, the following front-ends are shipped in the standard

VirtualBox package:</para>

<para><orderedlist>

<listitem>

<para><computeroutput>VirtualBox</computeroutput> is our graphical

user interface (GUI), which most of this User Manual is dedicated to

describing, especially in <xref linkend="BasicConcepts" />. While

this is the easiest-to-use of our interfaces, it does not (yet)

cover all the features that VirtualBox provides. Still, this is the

best way to get to know VirtualBox initially.</para>

</listitem>

<listitem>

<para><computeroutput>VBoxManage</computeroutput> is our

command-line interface for automated and very detailed control of

every aspect of VirtualBox. It is described in <xref

linkend="vboxmanage" />.</para>

</listitem>

<listitem>

<para><computeroutput>VBoxSDL</computeroutput> is an alternative,

simple graphical front-end with an intentionally limited feature

set, designed to only display virtual machines that are controlled

in detail with <computeroutput>VBoxManage</computeroutput>. This is

interesting for business environments where displaying all the bells

and whistles of the full GUI is not feasible.

<computeroutput>VBoxSDL</computeroutput> is described in <xref

linkend="vboxsdl" />.</para>

</listitem>

<listitem>

<para>Finally, <computeroutput>VBoxHeadless</computeroutput> is yet

another front-end that produces no visible output on the host at

all, but merely acts as a VRDP server. Now, even though the other

graphical front-ends (VirtualBox and VBoxSDL) also have VRDP support

built-in and can act as a VRDP server, this particular front-end

requires no graphics support. This is useful, for example, if you

want to host your virtual machines on a headless Linux server that

has no X Window system installed. For details, see <xref

linkend="vboxheadless" />.</para>

</listitem>

</orderedlist>If the above front-ends still do not satisfy your

particular needs, it is relatively painless to create yet another

front-end to the complex virtualization engine that is the core of

VirtualBox, as the VirtualBox core neatly exposes all of its features in a

clean API; please refer to <xref linkend="VirtualBoxAPI" />.</para>

</sect1>

</chapter>