SKR 5302: Advanced Distributed Computing

2. System Model: Distributed System

Physical model
Distributed Systems	Early	Internet-scale	Contemporary
Scale	Small	Large	Ultra-large
Heterogeneity	Limited (typically relatively homogeneous configurations)	Significant in terms of platforms, languages and middleware	Added dimensions introduced including radically different styles of architecture
Openness	Not a priority	Significant priority with range of standards introduced	Major research challenge with existing standards not yet able to embrace complex systems
Quality of Service	Not a priority	Significant priority with range of services introduced	Major research challenge with existing standards not yet able to embrace complex systems