1. CSE 221: Probabilistic Analysis of Computer Systems Topics covered: Pure death process Availability analysis (Sec. 8.3.1, 8.4.1)

2. Pure death process  Example:

3. Pure death process (contd..)  State transition diagram:

4. Pure death process (contd..)  Steady state or limiting probabilities:

5. Pure death process (contd..)  State-dependent rate:

6. Pure death process (contd..)  Example: Discovery of software bugs:  Example: Successive component failures

7. Availability analysis  Definition:

8. Availability analysis (contd..)  Example: 2-state system model  Balance equations:  Availability:

9. Availability analysis (contd..)  Numerical example: 2-state system model

10. Availability analysis (contd..)  Example: System model, with 2 components:  State space of the model:

11. Availability analysis (contd..)  State transition diagram:  Up & down states:

12. Availability analysis (contd..)  Balance equations:  Availability:

13. Availability analysis (contd..)  Numerical example: System with 2 components