The Tasty Seafood Restaurant is a large restaurant that specializes in fresh fish and seafood. Because its reputation for freshness is important to Tasty, it brings in a certain amount of each type of fish daily and, while trying to satisfy all of its customers, would rather run out of a type of fish than carry it over to the next day. After taking a table’s order, a waiter enters the order into a touch-screen terminal that is connected to a computer in the kitchen. The order is sent from the touch-screen terminal to the computer only after all of it has been entered.

At 8:00PM there are 10 servings of salmon, 15 servings of flounder, and eight orders of trout left in the kitchen. At 8:03 PM, waiter Frank starts entering an order that includes five servings of salmon, six of flounder, and four of trout. At the same time, on another touch-screen terminal, waitress Mary starts entering an order that includes one serving of salmon, three of flounder, and two of trout. At 8:05 PM, before the other two have finished entering their orders, waitress Tina starts entering an order that includes six servings of salmon, one of flounder, and five of trout. Frank finishes entering his order at 8:06 PM, Mary finishes at 8:07 PM, and Tina finishes at 8:09 PM.

a. What would the result of all of this be in the absence of locks?

b. What would the result be with a locking mechanism in place?

c. What would happen if versioning was in use?