[SeaBIOS] Problem accessing a small virtio disk

[Kevin Wolf]

Am 15.06.2012 14:42, schrieb Kevin O'Connor:
> On Thu, Jun 14, 2012 at 10:12:23AM +0200, Kevin Wolf wrote:
>> If you round up (which qemu does in this case as for some unknown reason
>> it always assumes a minimum of 2 cylinders), you pretend that the disk
>> is larger than the image really is and part of the virtual disk only
>> produces read/write errors. This is the only alternative implementation
>> I can see, and it's not a clear winner for me.
> 
> Maybe there is wisdom in setting a minimum of 2 cylinders.  That way
> the really tiny disks are still functional.

Yes, I can understand this reasoning and while it's still not fully
functional it should be enough to get something booted and then the OS
has a chance to ignore the whole geometry issues.

On the other hand, which OS with a virtio driver fits on a < 1 MB disk?
One of the more likely OSes for such an image is DOS, and it will
certainly fail when part of the pretended disk is neither writeable nor
readable. Of course, with a 0 cylinder disk it wouldn't work much
better, so we don't break much (1 cylinder disks maybe...), but I also
doubt if we gain anything.

Kevin