Re: [Qemu-devel] Support Questions

[Johannes Schindelin]

Hi,

On Tue, 13 Jun 2006, Joe Lee wrote:

> I came across a product called Iemulator and think it based on QEMU. If 
> so, I wanted to know how possible is it to re-brand qemu to something 
> similar to Iemulator.

It is based on QEmu. See http://www.iemulator.com/iemulator_faq.php, "Is 
iEmulator based on the BOCHS emulator?". It is perfectly legal. The core 
of QEmu is licensed under the LGPL, and accordingly, (at least 
some) sources of iEmulator are freely downloadable.

> Also, I am quite new to QEMU and virtualization in general and wanted to 
> know the difference between QEMU and product like OpenVZ.

OpenVZ is a virtualiser, i.e. it uses the hardware -- including the CPU -- 
of the host, and relies on the OS to handle the sharing parts. Therefore, 
you can not run unmodified kernels (or Windows for that matter) using 
OpenVZ.

QEmu is a system emulator, i.e. the hardware componentes are emulated. As 
for the CPU, QEmu uses a technique called "translation" or Just-In-Time 
compilation in order to execute the code. If the host CPU is of the same 
type as the emulated CPU, you can use KQEmu or QVEmu to kind-of virtualise 
the CPU instead.

> I suppose QEMU is more like VMware aimed at end users and OpenVZ would 
> be more for Enterprise servers.

Correct. The principal application for QEmu is to run a different OS in 
a window on your desktop. The principal application for OpenVZ or Zen is 
to run many virtual computers (servers) on one host.

Hth,
Dscho