CSE 130 Part 1

What is system

Set of interconnected components that has an expected behavior observed at the interface with its environment

Four issues of complexity

1. Emergent properties

2. Propagation of effects

3. Incommensurate scaling

4. Tradeoffs

5 signs of complexity

1. Large # of components

2. Large # of interconnections

3. Lots of irregularities

4. Long description

5. Large team of designers, implementers, or maintainers

2 sources of system complexity

1. Interaction of requirements

2. Increasing efficiency, utilization, or other measures of “goodness”

What increases complexity? (3)

1. Principle of escalating complexity

2. Principle of excessive generality

   1. Law of diminishing returns

How can we manage complexity? (5) Explain each.

1. Modularity: break big things into smaller pieces

2. Abstraction: break into components at logical points

3. Layering: build new layer from (already existing) lower layer

4. Hierarchy: combine smaller groups into one larger group

5. Naming: controls and manages all of the above

What is robustness principle?

Tolerant on inputs, Strict on outputs