Can a routine in one program call a routine in another program or even task?  Also is it poossible for a routine to be used in more than one task?  I would like clarification of task, programs and routines and how they relate to each other?  If all the work of tasks and programs is done in routines then I see the purpose of programs is to store local tags.  Also then I see the purpose of tasks is to help schedule work.  Is this true?