What are futures? In what languages do they appear? What precautions must the programmer take when using them? Explain the difference between AND parallelism and OR parallelism in Prolog. Give an...

What are futures? In what languages do they appear? What precautions must the programmer take when using them? Explain the difference between AND parallelism and OR parallelism in Prolog. Give an example of a “benign” race condition—one whose outcome affects program behavior, but not correctness.