Real-Time Systems Exam for BSc in Software Development & Computer Networking, Exams of Computer Science

Download Real-Time Systems Exam for BSc in Software Development & Computer Networking and more Exams Computer Science in PDF only on Docsity! Cork Institute of Technology Bachelor of Science (Honours) in Software Development and Computer Networking – Award (NFQ Level 8) Autumn 2006 Real-Time Systems (Time: 2 Hours) Instructions Answer any THREE questions. Note: Question 1 = 34 marks, All other questions = 33 marks. Real-Time Systems Reference Booklet Available. Examiners: Dr. J. Creagh Dr. J. Buckley Dr. A. Kinsella Q1. (a) (i) What are the main principles of HRT-HOOD? (3 marks) (ii) Referring to obligations, commitments, logical architecture and physical architecture, give an overview of the HRT-HOOD methodology. (6 marks) (iii) HRT-HOOD provides different object types. Clearly explain each object type. Diagrams/examples are required. (8 marks) (iv) The “classical mine drainage problem” may be developed in HRT-HOOD, presented by Burns and Wellings. For each HRT-HOOD object type: • Identify an example of this object type from the “classical mine drainage problem”. • Clearly describe the example object, and clearly indicate why it is of this object type? (10 marks) (b) Compare HRT-HOOD and ROPES methodologies. (7 marks) 2 Q2. (a) A window security system is part of a larger building security system. The window is protected by 4 laser lights that shine onto 4 laser sensors. If an intruder interrupts the laser light then the laser sensor is activated. Write an ADA task which monitors the 4 sensors every 50ms with a deadline of 6ms. If any sensor is activated, then the alarm is turned on and the lights are turned on. For actuators (alarm, lights) 1 = ON, 0 = OFF. Note: A register called ‘CSR’ controls the hardware. Refer to the reference booklet. A second register ‘READING’ is provided for reading a value from a sensor. A third register ‘WRITING’ is provided for writing a value to an actuator. (17 marks) (b) Write an ADA program illustrating the generic structure for handling sporadic activity. Comments required. (8 marks) (c) HRT-HOOD protected objects may easily be mapped to ADA code. Explain how this is possible by example. (8 marks) Q3. (a) (i) What is a cyclic alarm in OS–9? How does it work? (5 marks) (ii) Give an outline of a sample program which uses OS–9 cyclic alarms. Explain your program. (11 marks) (b) Write a generic C/C++ OS–9 program, which uses argv/argc to send a signal to a process. Describe how this program may be used from a telnet session. (9 marks) (c) With examples, illustrate the three principal uses of signals in OS–9 for real-time programs. (8 marks)