On May 15, 2008 11:54 am Miles Fidelman wrote:
> I've just started playing with Virtualbox - and boy do they make
> installing virtual machines easy. Download an .iso of a netinstall CD,
> point Virtualbox at it, and you have a window that behaves just like a
> normal install. Worked like a charm with both Debian Sarge and Etch
> images - doesn't seem to require any special bits in the guest O/Ss.
VirtualBox is based on a modified QEmu. It emulates a complete computer,
right down to the BIOS, including a bunch of standard hardware
components. As such, you don't need to modify OSes to run then on the VB
VM. VirtualBox doesn't (AFAIK) use the hardware virtualisation support
in Intel/AMD CPUs, and does a bunch of software tricks to run the VMs.
Not sure if it uses the KQemu accelerator module or not, or anything
similar. As such, running VMs in VirtualBox will be slower than other
solutions (that uses accelerator modules, hardware virtualisation
The closest comparable product for VirtualBox would probably be VMWare
Server or VMWare Workstation (in how they create a total virtual
computer, with a pretty management GUI). They work roughly the same
(doing everything in software).
Xen can also run unmodified guests OSes when installed on systems with
motherboards/CPUs that support Intel's VMX or AMD's SVM hardware
virtualisation extensions. Xen uses a modified QEmu to create the
hardware VM (emulating a bunch of standard hardware), and as such, you
can run unmodified guest OSes.
KVM can also run unmodified guest OSes, when installed on systems that
support VMX/SVM. KVM uses a modified QEmu to provide standard hardware,
and can run unmodified guests.
(As all but VMWare use a modified QEmu base, it's fairly easy to move VMs
between products. I've run Xen HVM images under KVM, and KVM images
And, of course, there's also QEmu. :)
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