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The Architecture of Distributed Systems

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The Architecture of Distributed Systems. Enterprise wide computing, networking and the desktop revolution. IT Architecture. Hardware and software Tools to access, package, deliver, & communicate information Standards, models, & control framework Configuration integrating components - PowerPoint PPT Presentation
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The Architecture of Distributed Systems Enterprise wide computing, networking and the desktop revolution
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Page 1: The Architecture of Distributed Systems

The Architecture of Distributed Systems

Enterprise wide computing, networking and the desktop revolution

Page 2: The Architecture of Distributed Systems

IT Architecture

• Hardware and software

• Tools to access, package, deliver, & communicate information

• Standards, models, & control framework

• Configuration integrating components– What is the difference between an IT

Architecture and an IT Infrastructure?

Page 3: The Architecture of Distributed Systems

IT Architecture and Infrastructure

• Architecture is overall blue print of how systems “fit” together– IS community has lost credibility b/c of failure in

this area.

• Infrastructure is a particular implementation of IT architecture with basic capabilities shared across business units.

• ??Why is an overall IT architecture important?

Page 4: The Architecture of Distributed Systems

Views of IT Infrastructure

• Utility– necessary and unavoidable service, often

viewed as administrative expense.– Firms with this view tend to offer fewest

infrastructure services– focus on lowering costs and not reengineering

processes.

Page 5: The Architecture of Distributed Systems

Views of IT Infrastructure

• Dependent– Tied to specific business programs in plan (ex.

Improve service quality)– infrastructure planning included in current

business plan– measured in short-term benefits– minimum requirement for implementing BPR

Page 6: The Architecture of Distributed Systems

Views of IT Infrastructure

• Enabling– continuous re-alignment of IT infrastructure with

firm strategy.– Long term strategy– infrastructure provides basis for flexibility, rapid

adaptation of future strategies– costs viewed as business investments– networks used extensively in business processes– increased up front costs

Page 7: The Architecture of Distributed Systems

Focus on IT Infrastructure

• Corp. IS departments moving from hw/sw to application/infrastructure focus– IS depts. in business of maintaining IT

infrastructure– s/w development reduced to modifying packages

for/by end users– CIOs starting to prefer CTO title– Why is IS dept. focus on infrastr. a recipe for

obsolescence or extinction of IS depts.?

Page 8: The Architecture of Distributed Systems

IT Architecture

• Applications– IT-enabled process redesign– Productivity applications– Competitive advantage

• Structure & controls– Standards, policies and procedures– Information models– System development methodologies

Page 9: The Architecture of Distributed Systems

IT Architecture• User interface

– GUI

– IO devices

• Tools & packages– Presentation & reporting

– Analysis & modeling

– Groupware

– Personal productivity

– DSS

Page 10: The Architecture of Distributed Systems

IT Architecture• Information Management

– Hardware

– OS

– DBMS

– Document management systems

– Information retrieval

• Communication management– Networks

– Gateways

– Email & file transfer

Page 11: The Architecture of Distributed Systems

IT Architecture Evolution

• Mainframes with “dumb” terminals– download/upload data– run mainframe programs (usu. batch)– little local processing

• Micros moved it to desktop

• Network computing model– centralized model with network replacing m/f

Page 12: The Architecture of Distributed Systems

The Computer System Concept

The Computer System ConceptCentral Processing UnitCentral Processing Unit

SecondaryStorageDevices

ControlUnit ALU

Primary StorageUnit

InputDevices

OutputDevices

Page 13: The Architecture of Distributed Systems

Changes in Computer Architecture

Changes in Computer Architecture

1930 1950 1957 1965 1975

prototype firstgeneration

secondgeneration

thirdgeneration

fourthgeneration

mechanicalrelay

vacuumtube

transistor integratedcircut

microprocessor

Page 14: The Architecture of Distributed Systems

Pentium ChipPentium Chip

Page 15: The Architecture of Distributed Systems

A Microprocessor A Microprocessor

control unit arithmeticlogic unit

128K temporary memory

input/outputcircuitry

systemclock

Page 16: The Architecture of Distributed Systems
Page 17: The Architecture of Distributed Systems

Performance vs. PricePerformance vs. Price

Page 18: The Architecture of Distributed Systems

Computer ClassificationsComputer Classifications

MainframesMainframes

MidrangeComputersMidrange

Computers

MicrocomputersMicrocomputers

Page 19: The Architecture of Distributed Systems

Networked Computer SystemsNetworked Computer Systems

ClientSystems

ServersServers

Host Systems/Superservers

Host Systems/Superservers

Page 20: The Architecture of Distributed Systems

How distributed are your systems?

• Where is the processing of data done?– Distributed processing

• How are the processors and other devices interconnected?– Processor connectivity

• Where is the information stored?– Distributed databases

• What rules or standards are used?– Protocols, transmission standards, etc.

Page 21: The Architecture of Distributed Systems

Distributed System Frameworks

• Organizational View– Corporate HQ– Regional HQ– Plant or Site– Department– Work Group– Individual

Page 22: The Architecture of Distributed Systems

Types of Distributed Systems

• Host-based hierarchical systems

Page 23: The Architecture of Distributed Systems

Host-based Hierarchy

Page 24: The Architecture of Distributed Systems

Types of Distributed Systems

• Host-based hierarchical systems

• Decentralized Stand-Alone Systems

Page 25: The Architecture of Distributed Systems

Decentralized Stand-alone System

Page 26: The Architecture of Distributed Systems

Types of Distributed Systems

• Host-based hierarchical systems

• Decentralized Stand-Alone Systems

• Peer-Peer LAN-Based Systems

Page 27: The Architecture of Distributed Systems

Peer-to-Peer LAN-based System

Page 28: The Architecture of Distributed Systems

Types of Distributed Systems

• Host-based hierarchical systems

• Decentralized Stand-Alone Systems

• Peer-Peer LAN-Based Systems

• Hybrid Enterprise-Wide Systems

Page 29: The Architecture of Distributed Systems
Page 30: The Architecture of Distributed Systems

Types of Distributed Systems

• Host-based hierarchical systems

• Decentralized Stand-Alone Systems

• Peer-Peer LAN-Based Systems

• Hybrid Enterprise-Wide Systems

• Client/Server Systems

Page 31: The Architecture of Distributed Systems

Some Common Client/Server Definitions

• “A network that uses smart nodes instead of dumb terminals”

• “Ability to distribute the workload”

• “Client manages the human interface; server manages the files”

Page 32: The Architecture of Distributed Systems

Client/Server Basic Architecture

Client

Server

Request Sent

Request Answered

Page 33: The Architecture of Distributed Systems

Client/Server Basic Architecture

Client Server BecomesClient

Server

Mainframe

Page 34: The Architecture of Distributed Systems
Page 35: The Architecture of Distributed Systems

Types of Servers

• Database Servers

• Resource Servers

• Application Servers

• Computation Servers

Page 36: The Architecture of Distributed Systems

Client/Server Computing (from Gartner Group [5])

Page 37: The Architecture of Distributed Systems

Benefits of Client/Server Computing

• Easy Database Access

• Downsizing Computer Resources

• Shared Hardware & Software Resources

• Increased Management Control– Remove “Islands of Automation”

• Scalable Architecture

Page 38: The Architecture of Distributed Systems

Benefits of Client/Server Computing

• Faster Application Development

• Reduced Application Development Backlog

• Increased Application Performance

Page 39: The Architecture of Distributed Systems

Barriers to Client/Server Computing

• Implementation Costs– Equipment– Systems Integration– Retraining IS Personnel

• MIS Culture

• Immature Technology

• Lack of Management Tools

Page 40: The Architecture of Distributed Systems

Barriers to Client/Server Computing

• Threat to Stable Operations

• Data Security

• Complexity

• Investment Payback

Page 41: The Architecture of Distributed Systems

Types of Distributed Systems

• Host-based hierarchical systems

• Decentralized Stand-Alone Systems

• Peer-Peer LAN-Based Systems

• Hybrid Enterprise-Wide Systems

• Client/Server Systems

• Network-Centric Systems– NC machines (see table 6-3 for summary costs)

Page 42: The Architecture of Distributed Systems

Network-Centric System

Page 43: The Architecture of Distributed Systems

Enterprise IT Architecture

• Enterprise architecture framework– Account for different roles in complex projects

• planner, owner, designer, builder, sub, user

– Account for components of complex systems• data models, functional models, network models,

people, time frames, underlying goals/motivations

• usually requires huge investment and corporate wide initiative

Page 44: The Architecture of Distributed Systems

Assimilating New IT

• Phased Assimilation Model– Technology Identification– Learning and Adaptation– Rationalization/Management Control– Maturity/Technology Transfer

Page 45: The Architecture of Distributed Systems

Types of IT Investments

• strategic system investments

• Informational system investments– EIS, DSS, management control, etc.

• Transactional system investments– support repetitive, operational processes

• Infrastructure investments– provide the base foundation of IT capabilities

Page 46: The Architecture of Distributed Systems

Types of IT Investments

Page 47: The Architecture of Distributed Systems

Conclusions

• Distributed systems have dominated IT development of 1990’s architectures

• C/S type may be moving to hybrid NC type

• No one predicted the rise of the Internet– Internet2?

• Complexity and speed of distributed systems will increase


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