[maemo-developers] AW: [maemo-developers] LiveCD under UML or qEMU?

[From: John B. Holmblad]

Steffen,

with respect to Microsoft's VirtualPC product, here is the url to the 
Microsoft www page for the product and, from there you can download an 
evaluation guide and a deployment  white paper:

            http://www.microsoft.com/windows/virtualpc/default.mspx

Although Microsoft will not specifically so indicate in their product 
literature, the product DOES support virtualization of the Linux OS. I 
have used VirtualPC to test out Ubuntu, RHEL and, now, the Maemo Live 
CD. In the case of Microsoft VirtualPC, the host operating system has to 
be Windows XP or Windows 2000. Furthermore I have successfully used 
VirtualPC on systems running Intel X86 hardware as well as on systems 
running AMD Athlon (64 bit) hw.


Also, please bear in mind that EMC has its own  product called VMWare 
(several versions actually, including one called VMWare workstation 5.0 
to complete more directly with Microsoft VirtualPC) that is in fact more 
mature and feature rich than the Microsoft product. Here is the url to 
the www page at the EMC www site for VMware Workstation 5.0

    http://www.vmware.com/products/desktop/ws_features.html

One important advantage of EMC's product is that  they have a version of 
the product that will run with Linux as the host OS and another version 
that will run with Microsoft Windows XP/2000 as the host os.


Although I have a copy of VMware, my operational experience is with the 
Microsoft VirtualPC product. It is very easy to create virtual machines 
with VirtualPC,  but, to run effectively, I recommend that the computer 
running the host OS have at least .5g or ideally 1gb or more or ram and 
have a fairly fast X86 processor, say  >= 2 ghz. Having said that, I 
have seen plenty of demos of software running as a VM where such demos 
were conducted using recent vintage laptops. My assumption is that these 
systems had ~2ghz or faster processors and at least .5gb of ram.

One nice feature of both VirtualPC and the VMware product is that you 
can have multiple VM's running at the same time (subject to having 
sufficient real ram on your host system and sufficient processor speed). 
Furthermore,  using the  virtual ethernet switch built into the VM 
software from Microsoft and from EMC, these VM's can communicate with 
each other and with your real network using their respective protocol 
stacks to access all network resources including DHCP, DNS, etc.. You 
can see where this leads, because now you can both test and demonstrate 
distributed applications that may require, e.g. a www server, a database 
server, and a client system (e.g. Nokia 770) all on the same machine.  
Well not yet, for the 770 because as far as I know there is, for now,  
no way to emulate the 802.11 wireless link. Furthermore,  for diagnostic 
purposes, you can run Ethereal on your Host OS to follow what is going 
on protocolwise in the VM environment.

Another feature of Microsoft VirtualPC and, I presume, VMWare 
Workstation 5.0, is that after you create an X86 virtual machine you can 
"capture" an .iso image (Microsoft's terminology) by browsing to the 
.iso on the file system of the host OS.  Equally, if you had first put 
("burned")  the .iso image onto a CD, you could "capture" the CD drive 
that is physically installed on the host system (i.e. bring it into the 
vm you have created) so that the X86 VM can load from the CD drive. I 
have used both approaches to install software into VM's I have created 
and it works fine.

The VM software also allows you to  pause, reset, and close any given 
VM. When you close the VM you are given the option to  save its current 
state, so that it can be restarted at a later point in time exactly 
where you left off. In the case of Microsoft VirtualPC, each virtual 
machine has three  files associated with it.  For example, a Windows 
2000 Pro VM that I created has the following three files   As you can 
see, the vhd file is the largest. It is the virtual hard drive for the 
system.


Windows 2000 Professional SP4 VM.vmc                      =>Virtual 
Machine Settings (config) File              (~13kb)

Windows 2000 Professional SP4 VM.vsv                        =>Virtual 
Machine Saved State File                    (~53kb)

Windows 2000 Professional SP4 VM Hard Disk.vhd     => Virtual Machine 
Virtual Hard Disk File           (~2.36 gb)


I should also mention that the "virtualization" performance penalty is 
actually not too bad, at least in the case of Microsoft VirtualPC. 
Microsoft people to whom I have spoken about the product say that the 
penalty is ~15 % or so for processor intensive applications. This is 
because the guest OS (i.e. the virtual machine) directly accesses  the 
X86 hardware, i.e.the  X86 instruction set is NOT emulated in software 
for the guest OS.

I hope this helps you get started.

-- 

Best Regards,

John Holmblad

Televerage International
GSEC,GCWN,GGSC-0100,NSA-IAM

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