1. Chapter 3 : Distributed Data Processing
Business Data Communications, 6e

2. Centralized Data Processing
Centralized computers, processing, data, control, support
What are the advantages?
Economies of scale (equipment and personnel)
Lack of duplication
Ease in enforcing standards, security

3. Centralized Data Processing May Consist Of:
Centralized Computers
Centralized Processing
Centralized Data
Centralized Control
Centralized Support Staff

4. Distributed Data Processing
Computers are dispersed throughout organization
Allows greater flexibility in meeting individual needs
More redundancy
More autonomy

5. Why is DDP Increasing? Dramatically reduced hardware costs
Dramatically increased distributed processing capabilities
Dramatically increased need for new applications and shorter development times
Ability to share data across multiple servers

6. DDP Pros & Cons There are no “one-size-fits-all” solutions Key issues
How does it affect end-users?
How does it affect management?
How does it affect productivity?
How does it affect bottom-line?

7. Benefits of DDP Responsiveness Availability
Correspondence to Org. Patterns
Resource Sharing
Incremental Growth
Increased User Involvement & Control
Decentralized Operation & Control
End-user Productivity
Distance & Location Independence
Privacy & Security
Vendor Independence
Flexibility

8. Drawbacks of DDP More difficulty test & failure diagnosis
More dependence on communication technology
Incompatibility of components
Incompatibility of data
More complex management & control
Difficulty in control of corporate information resources
Suboptimal procurement
Duplication of effort
Data integrity
Security

9. Client/Server Architecture
Combines advantages of distributed and centralized computing
Cost-effective, achieves economies of scale
Flexible, scalable approach

10. Intranets Uses Internet-based standards & TCP/IP
Content is accessible only to internal users
A specialized form of client/server architecture
Can be managed (unlike Internet)

11. Extranets
Similar to intranet, but provides access to controlled number of outside users
Vendors/suppliers
Customers
Utilizing Web technologies

12. Distributed applications
Vertical partitioning
One application dispersed among systems
Example: Retail chain POS, inventory, analysis
Horizontal partitioning
Different applications on different systems
One application replicated on systems
Example: Office automation

13. Other Forms of DDP Distributed devices Network management
Example: ATM machines
Network management
Centralized systems provide management and control of distributed nodes

14. Distributed data Centralized database Replicated database
Pro: No duplication of data
Con: Contention for access
Replicated database
Pro: No contention
Con: High storage and data reorg/update costs
Partitioned database
Pro: No duplication, limited contention
Con: Ad hoc reports more difficult to assemble

15. Networking Implications
Connectivity requirements
What links between components are necessary?
Availability requirements
Percentage of time application or data is available to users
Performance requirements
Response time requirements

16. Database Management Systems
Structured collection of data for multiple applications to use
Query language provides uniform access

17. Database Organization
Centralized – Common databases accessed by all processors
Replicated - Copy of central database stored at each processor
Partitioned – Individual databases for each processor

18. Centralized Databases
Advantages No duplication of data Little reorganization required
Disadvantages Contention among multiple processors accessing a single database Slow response time Single point of failure

19. Replicated Databases
Advantages No processor-database contention Shorter response time During failure, new copy can be obtained
Disadvantages High storage cost Redundant updates required High reorganization costs

20. Partitioned Databases
Advantages No duplication of data Size of database determined by application needs Short response time
Disadvantages Ad hoc management reports must access multiple databases

21. Networking Implications
What are the connectivity needs?
What are the availability needs?
What are the performance needs?