System Design

What is System Design?

the science of putting together system resources into a harmonious whole

What is System Optimisation?

maximise a set of performance metrics given a set of resource constraints

What are Common Optimisation Resources?

• time

• space

• computation

• cost

• labour

What are the Constraints to System Optimisation?

What is a System Bottleneck?

most constrained element in a system with respect to our optimisation metric

removing them improves performance metrics

What is Multiplexing?

use the same resource to service multiple requests without interference

What are the Dimensions of Multiplexing?

• time - CPU, I/O

• space - memory

• frequency - radio comms

What is Pipelining?

• special case of serially dependent subtasks

• depends only on the previous one in the execution chain

What is Batching?

• group tasks together and process them as a single unit rather than individually

• only works when 'overhead for N tasks' < 'N time overhead for one task'

What is Binding?

translate an abstraction into an instance

What is Indirection?

use a reference to access something, instead of directly

• provides flexibility because the reference can change without affecting the higher-level system

• dynamic binding allows easy optimisation for current conditions