Re: [Qemu-devel] Win98: how to exchange data with Linux

[Jim C. Brown]

On Tue, Jul 13, 2004 at 07:22:45PM +0200, Filip Navara wrote:
> Adrian Smarzewski wrote:
> [snip]
> 
> >It's a windows nt driver for ext2 partitions. maybe we could
> >change it so instead of writting files on real drive it will
> >pass commands to qemu? file system is not so important, but
> >this driver is lgpl'ed.
> 
> At first guys, you confuse file system drivers and storage drivers. The 
> file system drivers have de facto no knowledge on which disk are the 
> data located, (on Windows) they recieve an object and send Read/Write 
> requests to it (well, basicly, in reality there's also the cache manager 
> between them). At second, the idea can't work, even if you would have a 
> storage driver that uses some backdoor I/O port to access host disk, the 
> host OS can't access the same partition at the same time due to things 
> like caching (on both sides (guest/host)).
> 
> - Filip
> 
> 

Technically speaking, one could write a file system driver that talks to qemu
instead of going through a storage driver. (I didn't say it would be easy, just
barely possible.) Qemu could then translate attempts (to write a file on Windows
using this driver would cause qemu to write the file on linux's fs natively for
example). It is more work than its worth, but it is possible.

A modified user-net which emulated SMB protocol to the guest but did the i/o
natively on the host would do the same thing and be easier to implement.

Setting up tuntap or VDE is easiest of all. :)

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