Hmm, I can remember a time where apps came as either win95-version or NT (3.5.1). Or they came as two exes. one for NT, other for win95. So concerning todays programs, i see no need to be Win9x-compatible. Most apps work on NT or even need NT and don't run on 9x. But there's another idea: One could set the IOPL-Flag to 3 and let all programs access IO-ports.