Lecture 12 - Distributed systems: The overall architecture. In this chapter, the following content will be discussed: Describes seven types of distributed systems, defines the overall IT architecture and, discusses the importance of IT infrastructure.
Distributed Systems: The Overall Architecture Lecture 12 Contents n This lecture / chapter ă Describes ă Defines seven types of distributed systems the overall IT architecture and ă Discusses the importance of IT infrastructure Contents n Case examples include Northwest Airlines, an aerospace company, Chubb & Son Insurance Company, The SABRE Group, 3i, General Motors, FMC Corporation, Credit Suisse and the City of Sunnyvale Todays Lecture n Introduction ă Four Attributes ă When ă Two of Distributed Systems to Distribute Computing Responsibilities Guiding Frameworks Today’s Lecture cont n Seven Types of Distributed Systems ă Host-Based Hierarchy ă Decentralized ă Peer-to-Peer Stand-Alone Systems LAN-Based Systems Today’s Lecture cont n Seven Types of Distributed Systems ă Hybrid Enterprise wide Systems ă Client-Server Systems ă Internet-Based ă Web Services Computing Todays Lecture cont n Defining The Overall IT Architecture ă An Enterprise Architecture Framework ă The Coming Architecture: Service-Oriented Architecture n The Importance of the IT Infrastructure ă The Structure of the IT Infrastructure ă Three Views of Infrastructure Introduction - Definitions n An IT architecture is a blueprint A blueprint shows how a system, house, vehicle, or product will look and how the parts interrelate n Lately = rather than talk about hardware, software, data, communications etc as the components of computing, some people now refer only to applications and infrastructure Introduction – Definitions Cont n An IT infrastructure is the implementation of an architecture The IT infrastructure includes the processors, software, databases, electronic links, and data centers as well as the standards that ensure the components work together, the skills for managing the operation etc Introduction – The Evolution of Distributed Systems n First IT architecture = mainframes (batch processing) with dumb terminals (no processing capabilities) n With minicomputers = moved into departments but the ‘master-slave’ computing model persisted Processing was mainly centralized NORTHWEST AIRLINES Case example: Hybrid Enterprise wide Systems and Systems Integration cont • Purpose: improve revenue estimate accuracy by ‘auditing’ all the redeemed tickets (few airlines did this) • Developed with Accenture (Andersen Consulting) BIG $$$ NORTHWEST AIRLINES Case example: Hybrid Enterprise wide Systems and Systems Integration cont • The system integrates products from 11 vendors – – Uses a cooperative processing architecture and Integrates expert systems, image processing, relational databases, high resolution UNIX workstations, servers, and LANs NORTHWEST AIRLINES Case example: Hybrid Enterprise wide Systems and Systems Integration cont • • The Distributed Architecture – Mainframe, WANs, LANs etc – Data communication = integral – Image processing Revenue Accounting Process NORTHWEST AIRLINES Case example: Hybrid Enterprise wide Systems and Systems Integration cont Lessons learned: • Benchmark and prototype new technologies to verify vendors’ claims • An open architecture works on mission-critical applications NORTHWEST AIRLINES Case example: Hybrid Enterprise wide Systems and Systems Integration cont • Large distributed system projects need a vendor coordinator • Use of CASE was mandatory Huge system (65,000 workdays) which became a ‘model’ for airlines Types of Distributed Systems: Client-Server Systems n The ’90s version of distributed systems n Arose to take advantage of the processing capabilities of both host machines and PCs in the same system n Splits the computing workload between the client, which is a computer used by the user and can sit on the desktop or be carried around (e.g WAP mobile phone), and the server, which answers the request Types of Distributed Systems: Client-Server Systems cont n Figure 5-8 shows the possibilities for splitting work between clients and servers Three components being split are: ă Presentation ă Application ă Data (D) software: what user sees (P) software (A) Types of Distributed Systems: Client-Server Systems cont n Distributed presentation n Remote presentation n Distributed application function n Remote data management n Distributed database(s) Types of Distributed Systems: Client-Server Systems cont Another way to look at it = to view their architecture ă Preferred: three-tier architecture (see Fig.5-9): n Tier 3: the super server/mainframe Allows inclusion of legacy applications, short-lived and fast-changing data, and integrity rules Types of Distributed Systems: Client-Server Systems cont n Tier 2: specialized servers, dedicated to housing databases or middleware-software to ease connection between client and server Also, department-specific data that does not change often n Tier 1: clients (some of which could be portable) connected through network Summary ă Four Attributes ă When ă Two of Distributed Systems to Distribute Computing Responsibilities Guiding Frameworks ă Seven Types of Distributed Systems ă Host-Based Hierarchy Summary n Seven Types of Distributed Systems ă Hybrid Enterprise wide Systems ¨ Client-Server Systems ¨ Internet-Based ¨ Web Services Computing Summary… The Overall IT Architecture ă An Enterprise Architecture Framework ă The ‘Coming Architecture’: Service-Oriented Architecture ... Today’s Lecture cont n Seven Types of Distributed Systems ă Host-Based Hierarchy ă Decentralized ă Peer-to-Peer Stand-Alone Systems LAN-Based Systems Todays Lecture cont n Seven Types of Distributed. .. Distributed Systems ă Hybrid Enterprise wide Systems ă Client-Server Systems ă Internet-Based ă Web Services Computing Todays Lecture cont n Defining The Overall IT Architecture ă An Enterprise Architecture. .. Framework ă The Coming Architecture: Service-Oriented Architecture n The Importance of the IT Infrastructure ă The Structure of the IT Infrastructure ă Three Views of Infrastructure Introduction - Definitions