1. Design of SCS Architecture, Control and Fault Handling

2. Architectures and Control Models for SCS

3. Hardware faults specification design implementation interference ageing environmental SOME FAULTS ARE NOT SYSTEMIC

4. Software Faults specification design coding logical errors stack over-(or under-)flows use of unitialised variables ALL ARE SYSTEMIC

5. Safety Achieved by: fault avoidance fault removal fault detection fault tolerance

6. Fault Avoidance by Design partitioning readability, testability isolation readability, maintainability simplicity readability, testability, maintainability experimentation animation, trial software, simulation

7. Detect and Recover recovery blocks –acceptance –use of alternative modules –recovery points recovery point primary module acceptance test alternative module 1 acceptance test.

8. Fault Tolerance redundancy –hardware –software –information parity bits, checksums, error detecting codes, error correcting codes –temporal multiple calculation can detect transient faults diversity

9. Fault Tolerant Software n-version programming –separate implementations of function –results compared –some voting rule –cost overheads

10. Algorithmic Design simple no gotos use parameters not global references use for rather than while or repeat loops always cover default values use + and - in preference to * and / exceptions

11. Data Structures simple meaningful identifiers enumerated types strong typing static avoid pointers