Re: [Qemu-devel] QEMU with KNOPPIX

[Piotr Krysik]

Hi,

It can work in Windows, if you implement support 
of cloop-compatible image format in Qemu executable.

Just look at qcow compressed image format. Qemu 
doesn't require any additional services from host 
OS. The decompression is implemented by Qemu and 
is transparent for guest.

The example I gave is meant to help you evaluate 
benefits before starting implementation of cloop 
image format for Qemu.


Regards,

Piotrek

--- Kuniyasu Suzaki <address@hidden> wrote:
>  >>From: Piotr Krysik <address@hidden>
>  >>Subject: Re: [Qemu-devel] QEMU with KNOPPIX
>  >>
>  >>Hi,
>  >>
>  >>Probably a lot of CPU is spend on decompressing 
>  >>in CLOOP driver. Maybe it could be possible to 
>  >>do decompression natively and not under emulated 
>  >>CPU.
>  >>
>  >>You can start with an exercise. Setup CLOOP on 
>  >>your host (e.g. run Knoppix natively), then run 
>  >>another Knoppix inside Qemu, but give it access 
>  >>to your CLOOP device as an ide drive:
>  >>  qemu ... -cdrom /dev/cdrom -hda /dev/<your
> cloop>
>  >>Now try to use your host cloop device inside
> Qemu. 
> 
> Yes, this idea might be effective on QEMU/Linux.
> Same idea is used on user-mode-linux of our KNOPPIX.
>   
> http://unit.aist.go.jp/it/knoppix/uml/index-en.html
> 
> But we cann't mount CLOOP file on Windows.
> 
>  >>E.g. mount it instead of guest cloop:
>  >>  mount ... /dev/hda <guest cloop mount point>
>  >>Play with it. If the performance difference 
>  >>is substantial, it may justify extra effort 
>  >>to implement cloop compatible Qemu disk format 
>  >>(I guess qcow is not compatible with cloop), 
>  >>so it can be used on Windows.



                
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