We are working on an unstable system. When we try to run our sort on large arrays, sometimes the sorting algorithm will be forced to stop running in the middle of execution. (The array will be left in whatever state it was in at the time the algorithm stopped.) But we can start the algorithm over and run it again later. So we want to choose an algorithm that will make progress toward the goal even if it does not always finish executing. A good choice would be: sort.