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ReactOS in QEMU with the KQEMU accelerator module in Windows

Posted: Sun Nov 06, 2005 12:21 pm
by mikedep333
I hear about alot of people testing out ReactOS in QEMU, but with a little bit more effort, you can get the KQEMU accelerator module (virtualization module) setup.

This will not involve having something running on your computer all the time.

You need Windows NT/2000/XP/2003 for this, and at least around 192 megs of memory.

I don't feel like explaining the whole idea behind virtualization/emulation but basically it's a way to simulate a computer within an application, and virtualization is a faster method of doing so than emulation. QEMU is a free (GPL) emulator, and there is a freeware module to turn it into a virtual machine called KQEMU (as well as a free (GPL one) called qvm86, however that is more dififcult to setup I believe.). It fully supports ReactOS. ReactOS .2.8 and later have the virtual network card driver on the CD which is automatically installed during setup, and there are instructions for loading up the VGA driver in the wiki. The only real downside to using QEMU with KQEMU is that it is not as fast as VMware or Virtual PC.

The instructions here are only guaranteed to work with the build of QEMU that I link to and the versions of QEMU and KQEMU that I link to. I will update this as new versions become available.


1. Download and install the Free OS Zoo build of QEMU. ... -0.7.2.exe
This build in particular is important because it is compiled with support for KQEMU.

2. If you already have 7-zip, winrar, or any other archiver that supports gzip tarballs (.tar.gz files) great, skip to step 3. If not, download and install 7-zip (the regular, not the beta version unless you know what you're doing.)

3. Download KQEMU and extract it to a folder you can go to in a second.

4. Go to that folder, then the kqemu folder within it, and right click on kqemu.inf, and select install.

Now kqemu and a compatible build of qemu is installed. If you prefer to use your own command line options with qemu, do that, but make sure you run the step below when you want to run QEMU. If you prefer to use the menu that comes with this build of QEMU, read on.

5. Open up your start menu, programs, qemu (or whatever folder you decided to put the qemu start menu shortcuts in), then qemumenu...

6. Create a image file (qemu hard drive backup) hit C for create hard drive, enter a name like "ReactOS". You can make the drive as big as you want pretty much because the image won't use up the space on your hard drive until you use up that space in the QEMU machine. 4096 megs (4 gigs) is a safe bet if you must have a number. select the q-cow format.

7. We now need to determine how much memory to give ReactOS in QEMU. If you have 256 megs of memory, you would want 64 to 128 megs or so. If you have 384 megs or so, 192 will be good for most stuff you throw at ReactOS. You can always give ReactOS more, but in general you should give it 256 megs less or so than what your machine has. If you decided on 64 megs, you don't have to do anything. if you decided on more, select the amount of memory for ReactOS by hitting m at the main menu and then entering the amount.

8. Finally, hit I and either spell out the location of the reactOS ISO cd image (boot CD or live CD) or drag and drop the file from windows explorer.

You are now done setting up QEMU and KQEMU for ReactOS. You can quit out of the QEMU menu if you're still in it, or leave it open to run QEMU.


1. Open up the start menu, and go to run, then enter "net start kqemu". You will not have to do this again until you reboot or if you disable kqemu.

You can now start QEMU with your own command line options, or follow the step below using the menu.

2. Open up the QEMU menu from your start menu, and select 1 (or whatever number for the ReactOS qemu Image.)

You are now ready to start installing or running ReactOS.


While you are in QEMU, hit ctrl +alt + 2 to open up the QEMU monitor, and enter "info kqemu". It will then tell you if kqemu is enabled or not. Hit ctrl + alt + 1 to go back to regular QEMU usage.


Open up the start menu, go to run, and enter "net stop kqemu".

Enjoy and let me know how this works.


Posted: Thu Dec 29, 2005 2:28 pm
by jmmercy

I use extensively qemu and second mikedep333 on that. There is an
alternative, free of charge with vmware: vmplayer. It is faster although
less configurable but good information on modifying the free downloadable
vm is given in
It is compatible with qemu if one stick with the vmdk file format. You
can even export your disk images in any of the supported formats.
From the experience I had, install both as they have specific strengths
and weaknesses.

so when can we see your tutorial for vmplayer?

Posted: Fri Dec 30, 2005 11:45 am
by menn
pity the virtualization is nt only. anything you two recommend for 98? (i don't have nt or xp, always hated them.**) right now i just save what i'm working on and change qemu to "realtime" :)

**strangely, so far i am in love with r-o-s...

Re: so when can we see your tutorial for vmplayer?

Posted: Fri Dec 30, 2005 2:28 pm
by jmmercy
menn wrote:..tutorial..
No need for that, the mentionned link is all one needs. You can find a few
additionnal items related to serial port, all available by google'ing. There
is a forum in the vmware area giving some interesting advice and nice
pointers to virtual machines (that should normally run identically in qemu).
menn wrote:pity the virtualization is nt only. anything you two recommend for 98?
Run it under qemu or vmplayer :lol:, that is what I do now from
inside a Debian machine. Cannot play fancy games with it but that
is not the goal. PS: qemu works a little more slowly but better with w98
than vmplayer, I do not know why.
menn wrote:(i don't have nt or xp, always hated them.**)
Smart guy!
menn wrote:strangely, so far i am in love with r-o-s...
So am I. I can not wait until it gets better at installing specific hardware
and supporting standard install programs.