Guest section DW wrote:
<snip>
> As I found, this workaround does not help.
>
> Both the old and the new interface are very unreliable.
> And of course the new interface may not be present.
I can believe this :-(
> The comment was too optimistic. The implementation fails.
> You can see what is used (on i386) in setup.S.
> There is an int13 call to check whether hd1 exists.
> Unfortunately, we do not know which disk that is.
How horrible :-(
> This sentence presupposes that there is a geometry that one could detect.
> That assumption is false.
OK, then. If it isn't possible to detect geometry, how does Windows
determine geometry (even if it's geometry is "wrong"). I need to test
this more, but Windows needs partitions to begin and end on cylinder
boundaries, although the rules are a lot stranger than this. (long
story).
So all that matters to me is that the geometry on the software side,
no mattter what operating system, needs to be the same.
Does Windows determine the geometry from the partition table ONLY? If
that's the case, then there's no problem - we can use any geometry we
like, by writing it to the partition table (because Windows assumes each
partition ends on the end of a cylinder, the end head and sector values
should be the size of cylinders and heads, respectively). But I
suspect it uses BIOS calls to do I/O - at least on
some systems, which will screw everything up. Can someone confirm this?
Feel free to blow some of my assumptions out of the water. I "guessed"
this from experiment, but I don't have a wide range of
hardware/MS OS's/BIOSes to tell.
Andrew Clausen
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