Lecture 1 - Distributed Systems

Question 1

Why have distributed systems

Answer 1

•Distribute parts of job
–increase computational power

•Distribute data (or code)
–use desktops without duplicate data and avoid inconsistency problem

•Distribute the functionality of the system
–components
–internet-based applications

Question 2

What are the benefits of distributed computing?

Answer 2

• Higher performance
• Collaboration
• Higher reliability and availability
• Scalability
• Extensibility
• Higher productivity/ shorter development cycles
• Reuse
• Reduced cost

Question 3

What is the Web Service view based on IBM’s Web Service architecture?

Answer 3

Question 4

What was the 1-Tier business application like?

Answer 4

Question 5

What was the 2-Tier business application like?

Answer 5

Question 6

What was the 3-Tier business application like?

Answer 6

Question 7

What are the prevalent (important) needs of distributed systems?

Answer 7

–ability to scale
–internationalisation
–failure tolerance
–strong vendor support
–suitability for small and large apps

Question 8

What are the particular challenges of distributed systems?

Answer 8

•In general the following parties don’t “know” each other

• Security
• Multi-platform
• Multi-OS
• Multi-Vendor
• QoS - Quality of service (Overall performance / Perfomance seen by users on the network