class 3 distributed systems
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Asper School of Business 9.613 Using Information Technology Part-Time MBA, December 2001 Instructor: Bob Travica. Class 3 Distributed Systems. Outline. Key systems terminology. Concept of distributed systems. Types of distributed systems. Rationale for Distributing Systems. - PowerPoint PPT PresentationTRANSCRIPT
9.613 Using Information Technology
Class 3
Distributed Systems
Asper School of Business9.613 Using Information Technology
Part-Time MBA, December 2001Instructor: Bob Travica
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
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• 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)
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Key Systems Terminology (Computer-Based IS)
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DataProcess
User interface
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Key Systems Terminology
User
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SystemData, Processes
& User Interface
SystemData, Processes
& User Interface
OrganizationalGoals
OrganizationalGoals
Work DomainNeeds
Work DomainNeeds
System Requirements
System Design
Key Systems Terminology
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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
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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-ServerSystems
• Key role of networking
Centralization Continuum
high low
• Importance of standards for connectivity
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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)
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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)
low highSystem Distribution
Manufacturin
g
Fast food
franch
iser
Multinatio
nal Corp.
• Spatial dispersion of organization
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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)
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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.
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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.
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Client Middleware Server
Client ServerRequest
Service
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• Models of C/S architecture determined by different distribution patterns (Figure 5-8; e.g., S manages dataand shares processing with C, or S just manages data wileall processing on C)
Client-Server Models
• Try a bit different terms, taking server perspective (“remote” refers to client):
Distributed presentation (user interface)Remote PresentationDistributed ProcessingRemote ProcessingDistributed Data Management
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IT Infrastructure
• The fundamental IT capability (company-wide network anddatabases, 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
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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