[Qemu-devel] Re: Using Qemu to install Linux in a Windows XP

[Anand Kumria <wildfire@progsoc.org>]

On Sun, 14 Nov 2004 16:41:42 -0500, Brett Bonfield wrote:

> Also, would you consider making QEMUMenu.bat work with "dd for Win32" as
> well as it works with Zitu's program. dd for Win32 is available here:
> http://uranus.it.swin.edu.au/~jn/linux/rawwrite/dd.htm
> 
> The advantage it has over mkqemuimage.exe is that it can make any size
> images, at least so far as I can tell. The logic John Newbigin emailed
> goes as follows:
> 
> - - -
> 
> "The requirement is to create a big empty file which can be presented as a
> harddisk.  Under linux I would do this like this: dd if=/dev/zero
> of=myfile.img bs=1024k count=3000 This will give you 3000Meg.
> 
> The file will be 'initialised' with \000s.  It is possible to create a
> sparse file which is 'hollow' and will be allocated when you write to it. 
> That can cause problems with some programs though so it is best to avoid
> that unless you know it works.
> 
> Windows does not share the philosophy which makes that kind of command
> possible.
> 
> Under windows, sparse files are not supported so we can use the dd tool in
> a different way.  If you write anything to a large offset (say 3Gig) then
> all the space before that will be allocated.

That isn't true. Under Windows, use the mksparse command.

Not all filesystems have to support sparse files but NTFS (and perhaps
ext2/ext3 one day under Windows?) does.

<URL: http://www.insidewindows.info/mksparse.zip>

Cheers,
Anand

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