1. By Sophie Hutchinson (sxh07u)

2. Contents Introduction to Real-time systems Two main types of system Testing real-time software Difficulties with testing such software

3. Introduction What is a Real-time System? A real time system is one that is subject to real time constraints meaning that operations must produce a response within a given time. Examples include: Air traffic control systems Medical monitoring Weapons delivery systems Space navigation and guidance

4. Types of Real-time System There are two main types of real-time systems: Hard real-time system – Requires that operations must be completed within their deadline e.g. systems in space shuttles, fight control. Soft real-time system – Although it is emphasised that deadlines are important they are not as strict as in hard real-time systems.

5. Introduction to testing… How do we test a real-time software? There isnt one single method for testing real- time software. In order to test such software need to use several methods and strategies such as: White box testing Black box testing Sequence testing Integration testing

6. How do we test software in real-time systems? A strategy for testing real-time software should include: Low-level tests – single lines of code High-level tests – methods and functions In order to test such software one technique might be to generate and test sequences by applying time constraints in which they must be completed.

7. The 3-stage approach to testing real time software 1. Identification of tasks Output Testing Performance Testing 2. Incorporation of tasks Output Testing Performance Testing in a real environment 3. Integration Testing

8. Difficulties with testing Real-time software It is difficult to test a system that is running in real time due to factors such as: Time constraints Conventional methods are not applicable for real- time software This can lead to… Unpredictable outcomes

9. Summary A real-time system is subject to time constraints Two main types of real-time system No single way of testing this software Difficulties with testing such software

10. Any questions?

11. References http://msdn.microsoft.com/en-us/library/aa459157.aspx http://en.wikipedia.org/wiki/Real-time_computing G53SRP module page http://www.ndt.net/article/wcndt00/papers/idn235/idn23 5.htm http://www.ndt.net/article/wcndt00/papers/idn235/idn23 5.htm http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber= 139423 http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber= 139423