Re: [Qemu-devel] What can qemu do that vmware/virtual pc can't...article idea

[Oliver Gerlich <olig9@gmx.de>]

Udo 'Robos' Puetz wrote:
> Hi List.
> I'm in contact with one of the writers for the german (large) computer
> magazine c't (computer and technology) defending qemu (he neglected some
> features qemu has in one of his articles). Now he asks me for an article
> about what the "average user" would benefit from when he would use qemu instead
> of virtual pc/vmware (their "free" products, like player, ESX ...). The
> examples I named up to now where
> qemu -nographic -hda linux.img -kernel linux-2.6.17.6/arch/i386/boot/bzImage
> -append "console=ttyS0
> root=/dev/hda ide2=noprobe ide3=noprobe ide4=noprobe ide5=noprobe" -hdb
> fat:/mnt/data/Projekte/qemu/linux-test/bla
> doing a little linux kernel driver development learning this way. (Good free 
> pdf over at oreilly)
> Also, when testing OCFS2 (Oracle cluster fs 2) and not having a SAN/iSCSI
> system at hand I tried this:
> qemu -hda breezy.img -hdb ocsf2.img
> mounting that image once
> qemu -hda breezy.img -hdb ocsf2.img
> and now mounting it again in a second instance of qemu with slightly
> different network setup. That works with qemu, vmware desktop wouldn't take 
> the image a second time.
> Also, a demonstration LiveCD could be made to boot on a system but also to
> be played with qemu/qvm86 under win and linux (kqemu can't be re-distributed).
> There would be statically built qemu's on the CD with bat/bash skripts to
> start them (automatically).
> Also, qemu can run happily on the server awaiting connects via vnc. But some
> of the free products can do that too.
> 
> Soo, do you have any more ideas what qemu can what the (free) alternatives
> from M$/VMWare can't?
> Virtual PC can't handle USB _at_all_, what's the status of USB2.0 with qemu
> ( I think VMWare is still stuck on USB 1.1 )?
> VMWare Desktop (not free) has "unlimited" snapshots IIRC, ESX just recently
> got one snapshot functionality.
> 
> I can't say if I would do the article or the writer for the magazine but at
> least it would make qemu more visible to (more technical inclined) people ->
> good in my eyes.
> Thanks for your suggestions
> Cheers
> Udo
> 

Maybe qemu is not of so much use for the desktop user, but has its 
strength more in the direction of a generic "computer emulator" platform 
where other projects can build upon (see Argos or Free Live OS Zoo).
I'm not sure if Qemu really can compete with VMWare for a desktop 
virtualization software.

In my opinion the big advantage of Qemu is that it's open source. That 
makes it possible to use it as a basis for other projects; that also 
makes it possible to build the Live CD you mentioned. Another point is 
that an open source software is more likely to be shipped with Linux 
distros (OTOH VMPlayer is already available in some Ubuntu package 
repository, so this depends more on the distro maintainers). And if one 
wants to have a reliable platform to run legacy applications, an open 
source software has the advantage that you're not dependent on some 
company that might not exist in twenty years. Another point is the 
support of many host and guest platforms. But I think all this doesn't 
really help the desktop user.

What I think is quite nice is the USB tablet emulation. At least VMware 
requires that the VMWare tools are installed for mouse switching between 
host and guest. It's quite astounding that in Qemu this works (at least 
with Windows guest) without installing additional software.

So, IMHO you shouldn't try to praise Qemu as an end-user desktop 
virtualization software; presenting it to more technical users seems 
like a better idea.

Regards,
Oliver