Cook potatoes in enough boiling water to cover for 20 to 25 minutes or till tender. Cool; peel and cube.
Meanwhile, cook the chopped bacon till nearly done; drain on paper towels and set aside.
In a very large mixing bowl, combine the mayonnaise or salad dressing, onion, olives and pepper; mix well. Fold in the potatoes and cheese. Transfer to a 13x9x2-inch (3-quart rectangular) baking dish. Sprinkle the top of the potato mixture with bacon.
Bake, uncovered, in a 350 oven for about 30 minutes or till bubbly. Makes 12 to 14 servings.