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Class 7
Distributing Business and Systems
Asper School of Business - MBA Program6150 Management of Information Systems & Technology
April-June 2009Instructor: Bob Travica
Updated May 2009
Outline
• Strategies of Distributing Business & Systems
• Concept of Distributed Systems
• Client-Server Architecture
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• Messages for change leadership
Strategies of Distributing Business & Systems
• Dispersed org. entities can have different information needs –
low highSpatial dispersion
Manufacturer fo
r loca
l market a
nd
exports (s
ourcing & producti
on vs.
marketing & sa
les) Fast food
franch
iser
(McD
onald’s;
finances v
s.
sourci
ng, HR,
sales)
Multinatio
nal Manufactu
rer
(Ford; global so
urcing, in
ternational
R+D, producti
on, marketin
g…)
• Organizations dispersed in space (individuals, groups, units; e.g., salespeople in master case)
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• Information systems have to support different strategies of distributing business
• Inter-cultural aspect (master case)
Application Software (Functionality, Data processing)
Data(Data mgmt, Database)
User Interface(Presentation, input/output screens)
Information System Parts(resources, services)
Distributed Systems Concept: What Can Be Distributed
More
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• Any of these parts can be distributed – data, functionality, user interface. If all run by one computer, the system is centralized.
• An aspect of systems architecture (overall design of computing resources).
Distributed Systems: Data View
• Method 1: Central store, distributed access. Role of networks (3i, Northwest Airlines).
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• Rule #1 for distributed systems: Make data available where users need them.
• Method 2: Partition data store. Data fed and searched locally; occasional cross search.
More
Toronto VancouverWinnipeg
Purchasing
Production Sales
• Golden rule: Regardless of the specific architecture, users should not care if a system is distributed and in what manner. Access should be seamless.
• Method 3: Data partitions stored locally in real time, and partitions replicated across locations in certain intervals.
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PurchasingProduction
SalesPurchasingProduction
Sales
Purchasing Production
Sales
Toronto Vancouver
Winnipeg
• Computer networks – key role in distributed systems. Networks are part of IT Infrastructure (foundational systems serving entire enterprise).
Mainframe with dumb terminalsin departments
Departmentalstand-alone systems
Client-ServerSystems in/across
departments
Centralized Decentralized
• Data processing, data storage, user interface – a continuum showing levels of distribution of system parts in an enterprise:
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Distributed Systems Continuum
Client-Server (C/S) Architecture
• Most frequent today
• C/S systems distribute data, functionality or both between a machine that requests a service (client) and a machine that provides a service (server).
Client ServerRequest
Service
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• Division of responsibilities for data and functions, user interface usually on the client.
• Models of C/S architecture determined by different patterns of
sharing responsibility for data, functionality, and user interface
between computers.
Models of Client-Server Architecture
• Shared Processing (both server and client have certain functionality;
LAN w/ database server, Internet models – applets, Web services)
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Client - Input/Output screens- Query and Report code
Report creation Request
Report
Data lookup, input
Data table transfer
Note: Server is software, but it usually runs on a dedicated computer.
- Database (data)- Query and Report processing…
Database Sever
• Variant of Shared Processing with middleware
• * Example from HR domain: An employee is defined by an employee number, name, job position…, is associated with 1 department, reports to 1 manager, cannot have $0 salary, can have different benefit packages over time, etc.
Middleware
Database Server (Databases can be on a mainframe - “legacy system”)
(Code defining rules of business*; translation software)
Client (Applicationsoftware)
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• Variant of Shared Processing via the Internet (applets; Web services)
• Cases: SABRE
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- Upon getting data & applet, runsif-then calculations
Web Server
Application Server
Other systems
Mortgage InfoRequest Customer data
Customer Data +
Mortgage Applet
Client
Internet
Database ServerRequest
translated
Request
translatedWeb page
Web page with cust. data + applet
• Case: Chubb & Son
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Messages for Change Leadership
• If business is to get distributed, determine how can IS support this strategy.
• Be sensitive to company’s culture regarding its readiness for distributed systems (trust issues).
• Beware that data must be available where users need them, and that users should not worry whether the system is distributed or not.