How does a real-time system differ from time-share? In time-sharing, fast response is not desirable. In real-time systems, processing must not be completed within certain time constraints appropriate for the system. In time-sharing, fast response is desirable and required. In real-time systems, processing must be completed within certain time constraints. In time-sharing, fast response is not required. In real-time systems, processing must be completed within certain time constraints appropriate for the system. In time-sharing, fast response is desirable, but not required. In real-time systems, processing must be completed within certain time constraints appropriate for the system