Complex sentence: The reading and writing to hardware must be a small part of this time, e.g.200 microseconds, otherwise the phase shift makes tuning more difficult and there is less time available for the non-realtime programs, which may make the screen controls less responsive.
Split into simpler sentences: The reading and writing to hardware must be a small part of this time: e.g.200 microseconds. Otherwise the phase shift make tuning more difficult and it also leaves less time available for the non-realtime programs-e.g. making the screen controls less responsive.