>> * The realmode IDT is stuck (usually) at 0:0 with a limit of 0x3ff
> "Usually" ?
It is quite possible to relocate it using the LIDT instruction. I believe 
some systems actually do, to avoid corruption of the IDT. That should not 
pose a problem on DOS platforms, as M$ specify that one should use Int 21,25 
instead of accessing the IDT directly.
--- BBBS/NT v3.42 ToMmIk-5v
---------------