Levels of ​virtualisat​ion

So I've got XPSP2 running in Parallels on my Mac, and I was wondering how far I could go with Virtualisation and through how many OSes.

I don't own a copy of Virtual PC so unfortunately I can't use that, but I was thinking

OSX running Windows in Parallels, running Linux in Bochs running BeOS in VMWare running C64 under Frodo.

Any more suggestions? And have you ever been bored* (and dumb) enough to see how many machines you can have running on one box?



* I am waiting for QT and Boost to compile in the background, I'm not just bored bored, I am GCC is so sllooooow bored.

If I remember correctly you cannot run a virtual machine inside a virtual machine due to the virtualisation techniques employed. I remember a similar thread a while ago, I believe there is a picture in the picture forum, under media that depicts an attempt. (By Beetlejuice if I remember correctly)

Angus Higgins

I dunno, since the Linux that's running BeOS in VMWare is running inside Bochs (an emulator, it runs entirely in userspace).  That might get around the multiple VM restiction.  Only one way to find out, though!

Bochs runs okay inside Parallels, just downloading an RHat image.

x86 CPUs have four security "rings", which allow for protection at the instruction level.

Most OSs use 2 of these, Ring 0 - aka Kernel mode and Ring 3 - User mode. The way a lot of virtualisation software works is to run a copy of the Kernel in Ring 1 and then catches all the errors that occur from direct attempts at accessing the hardware and then emulating the results in software.

This is why you can't normally run a VM inside another VM, because you're already running in Ring 1 so you can't use that to trap hardware accesses. I say normally because you could, in theory write a VM that runs in Ring 2 (though this would seem bizarre) or run an entirely software emulator, which can do as it pleases.

Isn't Bochs just an emulator? Which probably explains why it is working

Rossj wrote:

Isn't Bochs just an emulator? Which probably explains why it is working

Yes.

CannotResolveSymbol wrote:



Rossj wrote:Isn't Bochs just an emulator? Which probably explains why it is working

Yes.

Ah, I thought the use of Bochs might change the situation, but I am not all that proficient with virtualisation software.

Angus Higgins

Rossj wrote:

I don't own a copy of Virtual PC so unfortunately I can't use that...

Ah, how sweet would be life if everything could be solved so easily....

PaoloM wrote:



Rossj wrote:I don't own a copy of Virtual PC so unfortunately I can't use that...

Ah, how sweet would be life if everything could be solved so easily....

I think he meant VirtualPC for Mac.

I think he meant for x86, so he can install Linux under XP.

VMware also doesn't install itself on a virtual machine.
It is fun watching something like Timbuktu or PCAnywhere try to cope when you attempt to remote back into the host machine from the VM.

jbwebb wrote:

It is fun watching something like Timbuktu or PCAnywhere try to cope when you attempt to remote back into the host machine from the VM.

Hehe, reminds me of the "How big a VNC loop can you make?" game we played in the office when it was new.

PaoloM wrote:

I think he meant for x86, so he can install Linux under XP.

I think the winner is .. Paolo .. XP is running under Parallels on the Mac.

AndyC wrote:



jbwebb wrote: It is fun watching something like Timbuktu or PCAnywhere try to cope when you attempt to remote back into the host machine from the VM.

Hehe, reminds me of the "How big a VNC loop can you make?" game we played in the office when it was new.

What was your record?

jbwebb wrote:

VMware also doesn't install itself on a virtual machine.

It installs itself in Parallels Unfortunately I am in bjam hell atm .. will try again later.

Rossj wrote:



It installs itself in Parallels Unfortunately I am in bjam hell atm .. will try again later.

Cool, didn't know that. If you try to install VMware on itself, it pops up a dialog that essentially translates as "Stop being so childish"