Grand Travel Airlines Has a Centralized, Mainframe-Based Information Systems Environment

question 10

Essay

Grand Travel Airlines has a centralized, mainframe-based information systems environment at its headquarters with telecommunications links to a server at each airport that it services. Each server, in turn, controls a LAN that includes a microcomputer at each check-in counter and gate. Check-in and other data taken in at the counters and gates is immediately transmitted to the mainframe at headquarters. Grand Travel maintains a relational database that includes data about its airplanes, pilots, flights, passengers, and reservations. It takes reservations over the Internet from travel agents and directly from passengers.
a. Devise a data security strategy for Grand Travel Airlines, incorporating appropriate data security measures.
b. Devise a backup and recovery strategy for Grand Travel Airlines. Bear in mind that its reservation system must be constantly operational so that it can check passengers in for flights and so that it does not lose future business.
c. Grand Travel does not wish to overbook its flights. Consider a situation in which there are 23 seats left on a particular flight on a particular date. Reservations agent Miller begins talking to a customer about the flight and reads the record showing 23 seats left. Two minutes later, agent Thompson begins talking to a customer about the very same flight and also reads that there are 23 seats left. Then, agent Miller's customer decides to book 4 seats on the flight, then agent Thompson's customer decides to book 7 seats on the flight.
i. What will happen in the absence of locks?
ii. What can happen in the presence of locks if the two agents are each trying to book multiple flights (or multiple legs of trips) for the two customers and access and lock the flights in different orders? What can be done about this?
iii. How would versioning handle these situations?