1. 9.613 Using Information Technology Class 3 Distributed Systems Asper School of Business 9.613 Using Information Technology Part-Time MBA, December 2001 Instructor: Bob Travica

2. 9.613 Using Information Technology Outline Key systems terminology Concept of distributed systems Types of distributed systems Rationale for Distributing Systems Conditions for Distributed Systems Distributed Systems Architectures Client-Server (C/S) Architecture Trends in Distributed Architectures

3. 9.613 Using Information Technology Data component - content and structure of data, storage (hardware), retrieval (software) - concern of database developers and system analysts Process component - data processing/transformation & movement -“programs” for processing & network software & hardware, functionality - concern of programmers and system analysts User interface (part of software - screens the user sees) More Key Systems Terminology (Computer-Based IS)

4. 9.613 Using Information Technology DataProcess User interface More Key Systems Terminology User

5. 9.613 Using Information Technology System Data, Processes & User Interface Organizational Goals Organizational Goals Work Domain Needs Work Domain Needs System Requirements System Design Key Systems Terminology More

6. 9.613 Using Information Technology IS Architecture (ISA) – an overall design of organizational information resources (specific systems & their design, IT types & standards, data models, networks, spatial layout) Cognate concepts (more specific than ISA): Systems Design (specific systems - above) IT Infrastructure (fundamental enterprise-wide IT; necessary for applications to run; e.g., enterprise-wide databases, operating systems) Information Architecture (just data component) Networks Architecture (communication protocols, topology, layout) Key Systems Terminology

7. 9.613 Using Information Technology Distributed System (DS) Concept Opposite to centralized system In DS, processing and/or data decentralized to certain degree Mainframe with dumb terminals Interconnected stand-alone systems Client-Server Systems Key role of networking Centralization Continuum highlow Importance of standards for connectivity

8. 9.613 Using Information Technology Why distribute systems? To support organizational requirements (efficiency, effectiveness) To support distributed organizational forms (country/region, division, process, teams; virtual organizations consisted of different firms) Technological reasons (efficiency, effectiveness in data, input, processing, transfer, storage)

9. 9.613 Using Information Technology Conditions for Distributed Systems Different data/information needs (FF franchises; regional division of production vs. sales – DDB example) Culture supporting decentralization (ex: PARC, change at IBM) Different data/information & processing needs (MN Corp.- accounting, marketing, production—input, quality control) lowhighSystem Distribution Manufacturing Fast food franchiser Multinational Corp. Spatial dispersion of organization

10. 9.613 Using Information Technology More Distributed Systems Architectures Interconnected Stand-Alone Systems (departmental processing and data management with communication links between departments; opposite to HBH) Peer LAN-Based System (equal distribution of processing and data management among peer computers) Client-Server Architecture Models (next slide)

11. 9.613 Using Information Technology Client-Server (C/S) Architecture C/S systems distributes either data or processing or both between a machine that requests a service (client) and a machine that provides a service (server). User interface is typically the client’s responsibility. More

12. 9.613 Using Information Technology Client-Server (C/S) Architecture C/S systems distributes either data or processing or both between a machine that requests a service (client) and a machine that provides a service (server). User interface is typically the client’s responsibility. More ClientMiddlewareServer ClientServer Request Service

13. 9.613 Using Information Technology Models of C/S architecture determined by different distribution patterns (Figure 5-8; e.g., S manages data and shares processing with C, or S just manages data wile all processing on C) Client-Server Models Try a bit different terms, taking server perspective (“remote” refers to client): Distributed presentation (user interface) Remote Presentation Distributed Processing Remote Processing Distributed Data Management

14. 9.613 Using Information Technology IT Infrastructure The fundamental IT capability (company-wide network and databases, large-scale computing facilities + essential technical and management solutions – ex: distributed vs. centralized arch. ) Similar to other infrastructures (city, transportation…; hard/technical + soft/social & cognitive components – policies, professions, jobs, knowledge) Serves as the basis for applications/services; Complex, costly, long-term, promised & intangible benefits

15. 9.613 Using Information Technology Trends in Distributed Architectures Pervasive computing (e.g., Jini from Sun Microsystems; any network used for connecting clients, servers and consumer devices; Java objects instead of device drivers) Peer-to-Peer (e.g., Napster - distributed data, Groove - distributed data; Internet used as network) Application Service Providers – distributed processing