>I contacted Microsoft about doing an Ada for Visual Studio.Net
  Is VS.Net a non-upwardly compatible replacement for Windows OSes?
Why does a compiler have to be modified to work with it?  What does
it mean that VS.Net "supports a language" - someone offers a compiler
for that language that works on that OS?  What fraction of current
compiler vendors (for all languages) will have to do how much work
to make their compiler work under VS.Net?  What prevents Java
language compilers, or Java VMs, from running under VS.Net?
  Could someone please explain what's going on?