Traditionally the three key areas of Acquisition Systems, Control Systems and Safety Systems have largely occupied three quite separate markets. Recently there have been developments that have created a move towards common solutions. A factor that has that has been a considerable influence in this has been the parallel move to Distribution. There are also strong moves towards Open-ness so that the Modern Integrated System is one that is Open, Distributed and encompasses Acquisition, Control and Safety. The paper elaborates on this and looks at the sort of host target development system that is needed in the design of such systems in order for them to become widely accepted. The work in the PiCSI project is then related to these needs.