General Questions about VirtualBox.
Q: VirtualBox is bundled with my Linux host. Can I get support here?
A: Sorry, but you can't get support here. The software which is bundled in the various Linux distros has been rebuilt by their developers (i.e. forked), with unknown changes and installed in unknown ways. We can't support the unknown. If you want to continue using the Linux fork then you must go to the appropriate fork site for support. To get support here you need to purge the repo version of VirtualBox then install the version from the
download page of this site.
Q: When I start my VM, I get an error stating that no boot medium was found. How do I solve this?
A: VirtualBox creates a simulation of the hardware of a PC. It does not simulate any software, so you need to install a guest operating system. Usually the guest installer comes on a CD, or even better just an image of that CD (called an ISO image, after the filesystem used on data CDs). Also please note that not all CDs are bootable, so do make sure that the CD or ISO which you have is in fact a bootable installer (people sometimes mistake a recovery CD or service pack CD for an installer).
Q: When use the 'Check for Updates..." function in the GUI it says that I'm running the most recent version of VirtualBox, however if I check the download page there is a newer version. Why is this?
A: We deliberately delay the update notification a little bit, to give us time to sort out potential download server problems. After one or two days you will get the expected result.
Q: I keep getting the message about a new version, but I prefer not to upgrade. Can I disable this?
A: Open the generic VB preferences from the main window and disable the automatic update check.
Q: Does VB support 64 bit guests?
A: Support for 64 bit guests was introduced at version 2.0.0. Note that hardware virtualization support is required to run 64bit guests, regardless of whether the host OS is 32bit or 64bit. See
FAQ: I have a 64bit host, but can't install 64bit guests.
HowTo: determine if VT-X/AMD-V is really activated and used by VirtualBox.
Another hint: after enabling VT-X/AMD-V in the BIOS you might need to switch the PC off completely, unplug it, or remove laptop battery for a minute. Ea:
Reboot the Host and go into the BIOS
disable vt-x, save BIOS settings, pause machine after bios boot messages
power down the Host (unplug power cord!)
start the Host and go into the BIOS
enable vt-x, save BIOS settings, pause machine after bios boot messages
power down the Host (unplug power cord!)
Boot the Host.
Q: I got my dual boot Windows XP running in VirtualBox using RAW Disk access, but I keep getting one core fully loaded. How do I solve this?
A: First, boot to your OS running on bare hardware.
- Make a copy of \windows\system32\hal???.dll and \windows\system32\ntkernl???.exe to whatever names you want.
- Change the processor type in hardware profile to ACPI single core. Do not reboot, but copy the new \windows\system32\hal???.dll and \windows\system32\ntkrnl???.exe to whatever names you want.
- BEWARE, all his names must be 8.3 based.
- Switch back to ACPI multicore - although this is not striclty needed, but in case in the future you do something wrong with your boot.ini, at least the default-named HAL and NTKERNEL will be there.
- Change your boot.ini to have two systems to boot (basically duplicate the existing one, change the name) and add the /KERNEL and /HAL options - here is an example:
Code: Select all
[boot loader]
timeout=30
default=multi(0)disk(0)rdisk(0)partition(1)\WINDOWS
[operating systems]
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP (multicore)" /fastdetect /NoExecute=OptIn /kernel=ntkrnlmp.exe /hal=halamp.dll
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP (singlecore)" /fastdetect /NoExecute=OptIn /kernel=ntkrnl.exe /hal=hala.dll
- Now by default, boot.ini is a hidden file on the root of the C: drive. There are several ways to open this file. Either change your Explorer settings to show hidden files and folders. go to System Properties tab Advanced and hit the Settings button on Startup and Recovery. Now you can use the Edit button to edit the file. A different method to use, is open a command prompt, go to the root of the drive and type notepad boot.ini.
There is a high chance that you can't save the file because it's read only. Change the file properties from Explorer or run Code: Select all
attrib -h -s -r c:\boot.ini
notepad c:\boot.ini
attrib +h +s +r c:\boot.ini
from the command prompt.
Now it works, you have multicore in native and no more 50% CPU usage in Linux+VB when you choose the single core HAL/NTKERNEL. The tradeoff is that when you boot, you have to press 2 or 3 keys before the computer actually boots (choose Linux/Windows, then in Windows Multi/Single core the the Hardware Profile).
Credits for this information to
Philippe.
Q: Why don't you make VirtualBox so it can run without a Host OS like VMware ESX?
A: VMware ESX, like Xen, is a type-1 hypervisor, also known as a bare-metal hypervisor, meaning that it's a "thin" OS that only does basic functions, like managing hardware resources and controlling the Virtual Machines.
VirtualBox, like VMware Workstation/Fusion, is a type-2 hypervisor, also known as a hosted hypervisor. It's an application that runs above an existing OS, which in this case is the one that manages the resources.
Sun Microsystems is already working on it's own type-1 hypervisor, named xVM Server.
Q: I am running Linux and my kernel has just been upgraded. Do I need to do anything?
A: VirtualBox links its device drivers against the kernel during installation. The drivers link into addresses inside the kernel. The correct addresses may change when your kernel is upgraded, and as a result VirtualBox can start to cause otherwise inexplicable errors. After kernel upgrade it is always sensible to relink your kernel drivers. This is by running
vboxdrv with the
setup option. The command that you will therefore typically run is
sudo /etc/init.d/vboxdrv setup. If you install the DKMS package, all kernel modules are installed automatically when you install a new kernel.
Q: So is VirtualBox based on QEMU?
A: No, VirtualBox is independently developed. It does use QEMU for some real-mode execution (when using Software Virtualization) and for emulation of certain more complicated instructions (when in Hardware Virtualization VT-x/AMD-V mode). But this accounts for a tiny fraction of the time a typical session runs.
Q: I want to use more than one processor in my VM, but I can't move the slider. Why is this?
A: You need hardware virtualization in order to use SMP (multi processor support). The same requirements are in order as for running 64 bit Guests. AMD-V/VT-x need to be available in your CPU, your motherboard needs to support this and it needs to be enabled in your BIOS. I/O APIC and ACPI are also needed. More information can be found in the user manual, chapter 3.7.2.2.
Q: I want to move my VM to a different host, how do I do that?
See
Howto: Move a VM.