I want to write some programs in assembly (please don't suggest a HLL as I won't use one) on my A2000. I want to do file I/O, some graphics on a HAM6 screen, and perhaps audio as well. Now the question is how to go about it. Looking at bits of source code and documentation that I've been able to find, the method of disabling the OS and accessing hardware registers directly seems to be very clear. But, can OS calls still be used for file I/O in this case? And where could I learn to open a custom screen and play audio the OS-friendly way anyways?