ok, but is there a header file where I can find these functions? thx JR > I have programmed a part of the program and I can make an executable. > When I run > the executable I get the following error: 'General protection fault'. I think this means > that I have to reserve some memory to be able to run some assembly instructions. So I > thought it could be something about the 'ioperm' function, but I am not sure. > > Is there someone who knows why I get this error and how I can fix it? Are you trying to do out/in in a userland application? That of course, won't work. *But* there are the private (!) calls read_isa_io() and write_isa_io() in libroot.so - maybe they can be of service for you. Bye, Axel.