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

Pure death process  Example:

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

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

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

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

Availability analysis  Definition:

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

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

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

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

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

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