| 1 | <?xml version="1.0" encoding="UTF-8"?>
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| 2 | <!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN"
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| 3 | "http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd">
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| 4 | <chapter id="KnownIssues">
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| 5 | <title>Known limitations</title>
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| 6 |
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| 7 | <para>This sections describes known problems with VirtualBox
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| 8 | $VBOX_VERSION_STRING. Unless marked otherwise, these issues are planned to
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| 9 | be fixed in later releases.</para>
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| 10 |
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| 11 | <itemizedlist>
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| 12 | <listitem>
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| 13 | <para>The following <emphasis role="bold">Guest SMP (multiprocessor)
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| 14 | limitations</emphasis> exist:<itemizedlist>
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| 15 | <listitem>
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| 16 | <para><emphasis role="bold">Poor performance</emphasis> with
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| 17 | 32-bit guests on AMD CPUs. This affects mainly Windows and Solaris
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| 18 | guests, but possibly also some Linux kernel revisions. Partially
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| 19 | solved in 3.0.6 for 32 bits Windows NT, 2000, XP and 2003 guests.
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| 20 | Requires 3.0.6 or higher Guest Additions to be installed.</para>
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| 21 | </listitem>
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| 22 |
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| 23 | <listitem>
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| 24 | <para><emphasis role="bold">Poor performance</emphasis> with
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| 25 | 32-bit guests on certain Intel CPU models that do not include
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| 26 | virtual APIC hardware optimization support. This affects mainly
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| 27 | Windows and Solaris guests, but possibly also some Linux kernel
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| 28 | revisions. Partially solved in 3.0.12 for 32 bits Windows NT,
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| 29 | 2000, XP and 2003 guests. Requires 3.0.12 or higher Guest
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| 30 | Additions to be installed.</para>
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| 31 | </listitem>
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| 32 | </itemizedlist></para>
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| 33 | </listitem>
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| 34 |
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| 35 | <listitem>
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| 36 | <para><emphasis role="bold">64-bit guests on some 32-bit host systems
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| 37 | with VT-x</emphasis> can cause instabilities to your system. If you
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| 38 | experience this, do not attempt to execute 64-bit guests. Refer to the
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| 39 | VirtualBox user forum for additional information.</para>
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| 40 | </listitem>
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| 41 |
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| 42 | <listitem>
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| 43 | <para>For <emphasis role="bold">Direct3D support in Windows
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| 44 | guests</emphasis> to work, the Guest Additions must be installed in
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| 45 | Windows "safe mode". Press F8 when the Windows guest is booting and
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| 46 | select "Safe mode", then install the Guest Additions. Otherwise Windows'
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| 47 | file protection mechanism will interfere with the replacement DLLs
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| 48 | installed by VirtualBox and keep restoring the original Windows system
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| 49 | DLLs.</para>
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| 50 | </listitem>
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| 51 |
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| 52 | <listitem>
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| 53 | <para><emphasis role="bold">Guest control.</emphasis> On Windows guests,
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| 54 | a process lauched via the guest control execute support will not be able
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| 55 | to display a graphical user interface <emphasis>unless</emphasis> the
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| 56 | user account under which it is running is currently logged in and has a
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| 57 | desktop session.</para>
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| 58 |
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| 59 | <para>Also, to use accounts without or with an empty password, the
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| 60 | guest's group policy must be changed. To do so, open the group policy
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| 61 | editor on the command line by typing
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| 62 | <computeroutput>gpedit.msc</computeroutput>, open the key
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| 63 | <emphasis>Computer Configuration\Windows Settings\Security
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| 64 | Settings\Local Policies\Security Options</emphasis> and change the value
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| 65 | of <emphasis>Accounts: Limit local account use of blank passwords to
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| 66 | console logon only</emphasis> to <emphasis>Disabled</emphasis>.</para>
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| 67 | </listitem>
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| 68 |
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| 69 | <listitem>
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| 70 | <para><emphasis role="bold">Guest multi-monitor support</emphasis> is
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| 71 | currently only supported with Windows guests.</para>
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| 72 | </listitem>
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| 73 |
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| 74 | <listitem>
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| 75 | <para><emphasis role="bold">Disabled host I/O caches.</emphasis>
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| 76 | Disabling the host I/O cache (see <xref linkend="iocaching" />) will
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| 77 | yield poor performance with VHD and sparse VMDK files as these do not
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| 78 | currently support asynchronous I/O. This does not apply to VDI files and
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| 79 | raw disk/partition VMDK files, which do support async I/O. This
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| 80 | restriction will be lifted in a future maintenance update.</para>
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| 81 | </listitem>
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| 82 |
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| 83 | <listitem>
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| 84 | <para><emphasis role="bold">Compacting virtual disk images is limited to
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| 85 | VDI files.</emphasis> The <code>VBoxManage modifyhd --compact</code>
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| 86 | command is currently only implemented for VDI files. At the moment the
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| 87 | only way to optimize the size of a virtual disk images in other formats
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| 88 | (VMDK, VHD) is to clone the image and then use the cloned image in the
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| 89 | VM configuration.</para>
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| 90 | </listitem>
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| 91 |
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| 92 | <listitem>
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| 93 | <para><emphasis role="bold">OVF import/export:</emphasis><itemizedlist>
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| 94 | <listitem>
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| 95 | <para>OVF localization (multiple languages in one OVF file) is not
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| 96 | yet supported.</para>
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| 97 | </listitem>
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| 98 |
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| 99 | <listitem>
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| 100 | <para>Some OVF sections like StartupSection,
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| 101 | DeploymentOptionSection and InstallSection are ignored.</para>
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| 102 | </listitem>
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| 103 |
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| 104 | <listitem>
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| 105 | <para>OVF environment documents, including their property sections
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| 106 | and appliance configuration with ISO images, are not yet
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| 107 | supported.</para>
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| 108 | </listitem>
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| 109 |
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| 110 | <listitem>
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| 111 | <para>Remote files via HTTP or other mechanisms are not yet
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| 112 | supported.</para>
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| 113 | </listitem>
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| 114 | </itemizedlist></para>
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| 115 | </listitem>
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| 116 |
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| 117 | <listitem>
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| 118 | <para><emphasis role="bold">Seamless mode</emphasis> does not work
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| 119 | correctly with Linux guests that have 3D effects enabled (such as with
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| 120 | compiz-enabled window managers).</para>
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| 121 | </listitem>
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| 122 |
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| 123 | <listitem>
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| 124 | <para><emphasis role="bold">Mac OS X hosts:</emphasis><itemizedlist>
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| 125 | <listitem>
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| 126 | <para>The numlock emulation has not yet been implemented.</para>
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| 127 | </listitem>
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| 128 |
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| 129 | <listitem>
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| 130 | <para>The CPU frequency metric is not supported.</para>
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| 131 | </listitem>
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| 132 |
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| 133 | <listitem>
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| 134 | <para>3D OpenGL acceleration, in particular with Linux guests that
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| 135 | have 3D effects enabled (such as with compiz-enabled window
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| 136 | managers).</para>
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| 137 | </listitem>
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| 138 |
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| 139 | <listitem>
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| 140 | <para>Memory ballooning is not supported.</para>
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| 141 | </listitem>
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| 142 | </itemizedlist></para>
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| 143 | </listitem>
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| 144 |
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| 145 | <listitem>
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| 146 | <para><emphasis role="bold">Mac OS X Server guests:</emphasis>
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| 147 | <itemizedlist>
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| 148 | <listitem>
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| 149 | <para>Mac OS X Server guests can only run on a certain host
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| 150 | hardware. For details about license and host hardware limitations,
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| 151 | please see <xref linkend="intro-macosxguests" />.</para>
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| 152 | </listitem>
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| 153 |
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| 154 | <listitem>
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| 155 | <para>VirtualBox does not provide Guest Additions for Mac OS X
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| 156 | Server at this time.</para>
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| 157 | </listitem>
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| 158 |
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| 159 | <listitem>
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| 160 | <para>The graphics resolution currently defaults to 1024x768 as
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| 161 | Mac OS X Server falls back to the built-in EFI display support.
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| 162 | See <xref linkend="efividmode" /> for more information on how to
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| 163 | change EFI video modes.</para>
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| 164 | </listitem>
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| 165 |
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| 166 | <listitem>
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| 167 | <para>Even when idle, Mac OS X Server guests currently burn 100%
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| 168 | CPU. This is a power management issue that will be addressed in a
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| 169 | future release.</para>
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| 170 | </listitem>
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| 171 |
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| 172 | <listitem>
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| 173 | <para>Mac OS X Server guests only work with one CPU assigned to
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| 174 | the VM. Support for SMP will be provided in a future
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| 175 | release.</para>
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| 176 | </listitem>
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| 177 |
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| 178 | <listitem>
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| 179 | <para>Depending on your system and version of Mac OS X Server, you
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| 180 | might experience guest hangs after some time. This can be fixed by
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| 181 | turning off energy saving (set timeout to "Never") in the system
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| 182 | preferences.</para>
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| 183 | </listitem>
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| 184 |
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| 185 | <listitem>
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| 186 | <para>By default, the VirtualBox EFI enables debug output of the
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| 187 | Mac OS X Server kernel to help you diagnose boot problems. Note
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| 188 | that there is a lot of output and not all errors are fatal (they
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| 189 | would also show on your physical Mac). You can turn off these
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| 190 | messages by issuing this command:<screen>VBoxManage setextradata "VM name" "VBoxInternal2/EfiBootArgs" " "</screen>To
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| 191 | revert to the previous behavior, use:<screen>VBoxManage setextradata "VM name" "VBoxInternal2/EfiBootArgs" ""</screen></para>
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| 192 | </listitem>
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| 193 | </itemizedlist></para>
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| 194 | </listitem>
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| 195 |
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| 196 | <listitem>
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| 197 | <para><emphasis role="bold">Solaris hosts:</emphasis> <itemizedlist>
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| 198 | <listitem>
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| 199 | <para>There is no support for USB devices connected to Solaris 10
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| 200 | hosts.</para>
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| 201 | </listitem>
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| 202 |
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| 203 | <listitem>
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| 204 | <para>USB support on OpenSolaris hosts requires version snv_124 or
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| 205 | higher. Webcams and other isochronous devices are known to have
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| 206 | poor performance.</para>
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| 207 | </listitem>
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| 208 |
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| 209 | <listitem>
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| 210 | <para>No ACPI information (battery status, power source) is
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| 211 | reported to the guest.</para>
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| 212 | </listitem>
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| 213 |
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| 214 | <listitem>
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| 215 | <para>No support for using wireless adapters with bridged
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| 216 | networking.</para>
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| 217 | </listitem>
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| 218 | </itemizedlist></para>
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| 219 | </listitem>
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| 220 |
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| 221 | <listitem>
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| 222 | <para><emphasis role="bold">Guest Additions for OS/2.</emphasis> Shared
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| 223 | folders are not yet supported with OS/2 guests. In addition, seamless
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| 224 | windows and automatic guest resizing will probably never be implemented
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| 225 | due to inherent limitations of the OS/2 graphics system.</para>
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| 226 | </listitem>
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| 227 | </itemizedlist>
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| 228 | </chapter>
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