Distributed Systems

1. Distributed Systems Lecture 13

2. Today Lecture • AN AEROSPACE COMPANY Case example: Client-Server Systems • CHUBB & SON INSURANCE COMPANY Case example: Internet-Based Computing • THE SABRE GROUP Case example: Internet-Based Computing • The IT Infrastructure

3. AN AEROSPACE COMPANY Case example: Client-Server Systems • Systems group’s goal = never build monolithic applications again • Builds client-server systems with: • Application code on the clients • Data on the servers

4. AN AEROSPACE COMPANY Case example: Client-Server Systems Cont.. • Communication middleware software shared. • Object oriented technology, most from a library • Data = at the heart of the architecture is a repository which allows the reuse of objects

6. AN AEROSPACE COMPANY Case example: Client-Server Systems cont. • Network = integral part of the architecture. Each company site has three components: • Desktop machines • Servers • One or more site hubs

7. AN AEROSPACE COMPANY Case example: Client-Server Systems cont. • Architecture = ‘remote data management’. Data resides on servers and applications reside on clients • Company uses the distribution function and remote data management because they minimize total costs

8. Types of Distributed Systems:5. Client-Server Systems cont. • Benefits of Client-Server Computing: • Better access to information: • Allow companies to compete better.

9. Types of Distributed Systems:5. Client-Server Systems cont. • Improved customer service • Ability to communicate customer needs, and • Anticipate customer needs. • Reduce cycle times and

10. Types of Distributed Systems:5. Client-Server Systems cont. • Empowered employees: • Blend autonomy of PCs with system wide rules and connectivity of traditional IS. • Shifts focus of computing to users

11. Types of Distributed Systems:5. Client-Server Systems cont. • Benefits of Client-Server Computing (cont.): • Increases organizational flexibility: • allows new technology to be added more easily without affecting rest of system • streamlines work flow between functional areas • encourages people to work together via networks • Supports new organizational structures via its connectivity

12. Types of Distributed Systems:5. Client-Server Systems cont. • Drawbacks: • Not lower in cost than mainframes because they entail so much coordination • Easier for users, far more complex for IS (drawback?) • What looked like simple connections have turned into large, often fragile, complex systems

13. Types of Distributed Systems:6. Internet-Based Computing • In the late 1990s, the client-server trend was ‘interrupted’ (augmented?) by the ‘Internet’ • Model of a distributed system includes the Internet (heart?) • The tenets of client-server remain • Network-centric computing = a computer and a cloud (Figure 5-11)

15. Types of Distributed Systems:6. Internet-Based Computing cont. • Network computers have (had?) not taken off (desktops) but the concept of utilizing programs off the Internet has • ‘Network’ computers (thin clients, toasters etc.) now = coming into their own!

16. Types of Distributed Systems:6. Internet-Based Computing cont. • Thin clients = logical for hand held but now = increasingly popular for the ‘desktop’ • Updating new versions of software • Authorized software (firm and purchased) • ‘One copy’ of software

17. CHUBB & SON INSURANCE COMPANY Case example: Internet-Based Computing • The company took advantage of the Internet by converting their legacy cargo certificate issuance system to a Java-based extranet application

18. CHUBB & SON INSURANCE COMPANY Case example: Internet-Based Computing Cont.. • It has also done the same with other applications. • All the apps feed into Chubb’s mainframe but have a Java-based Web front end so that client machines only need access to the Web to perform the application

19. THE SABRE GROUP Case example: Internet-Based Computing • This airline reservation company is working with Nokia (the handheld phone manufacturer) to create a real-time, interactive travel service delivered via mobile phone

20. THE SABRE GROUP Case example: Internet-Based Computing Cont.. • The service draws on SABRE’s online corporate travel purchasing system and Nokia’s server (which transmits the travel information to a wireless network and to its Internet-enabled phones). • Qantas etc. also have and doesn’t need to be web-enabled mobiles e.g. text messaging

21. Types of Distributed Systems:6. Internet-Based Computing cont. Server-Based Computing • With more use of laptops which do not have strong security features • Updating en masse is not easy • Even individual downloads can require helpdesk support

22. Types of Distributed Systems:6. Internet-Based Computing cont. • Solution = server based computing • Applications reside on corporate servers rather than on laptops. • Applications can be securely accessed by any device, they can be updated directly on the server, and they do not have to be tailored to run on specific machines

23. 3i Case example: Server-Based Computing (mobile) • UK based venture capital firm. • Needed to give its investment professionals anytime-anywhere access to its systems • Remote employees dial in (secure modem). • Using Windows terminal server software and Citrix software = the create a ‘virtual office’ for themselves

24. Types of Distributed Systems:6. Internet-Based Computing cont. Peer-to-Peer Computing • This form of Internet computing distributes a task over a wide number of computers (peers) connected to the Internet. • This grassroots movement, like the open source movement, is now taken seriously by some corporations. It became famous with Napster, the music swapping P2P network

25. Types of Distributed Systems:6. Internet-Based Computing cont. Peer-to-Peer Computing • The main issue now is how to make money in this environment. One answer: subscriptions, where people pay for access rather than for ownership

26. Types of Distributed Systems:7. Web Services • This second-generation Internet-based distributed system gives software modules URLs (Internet addresses) so they can be called upon to perform their function as a service via the Internet. • This development will permit widespread computer-to-computer use of the Internet. One computer program or Web Service makes a request of another Web Service to perform its task (or set of tasks) and pass back the answer

27. Types of Distributed Systems:7. Web Services cont. • Hot topic (the future?): • Next generation of distributed systems (big!) • Makes the Internet the hub of computing • Permits flexible systems not possible before

28. Types of Distributed Systems:7. Web Services cont. 4. Releases companies from ‘building’ and maintaining systems ‘in house’ • Will draw on existing systems. • Wrapping – encapsulate functionality from an existing application in an XML envelope • Exposing – for use by others • The promises go on! And the vying for position!

29. Types of Distributed Systems:7. Web Services cont. • Web Services Standards: • Three software standards: • XML (eXtensible Markup Language) • WSDL (Web Services Definition Standard) • UDDI (Universal Discovery, Description, and Integration

30. Types of Distributed Systems:7. Web Services cont. • Web Services Standards: • Three communication standards • SOAP (Simple Object Access Protocol) • HTTP (HyperText Transfer Protocol) • TCP/IP (Transmission Control Protocol / Internet Protocol)

31. Types of Distributed Systems:7. Web Services cont. • Significance of Web Services • Viewing IS as proprietary has led to rigid business processes, which are slow to change and respond to market changes. • Web Services offers an IT architecture based on the openness of the Internet. Rather than build proprietary systems, companies can obtain the functionality they need from the Internet

32. Types of Distributed Systems:7. Web Services cont. • This modularity permits handling a huge variety of possibilities by mixing and matching, and allows easier cross-company system linking. • Companies thus only pay for the functionality they use when they use it, which reduces the number of IT assets companies need to house and maintain

33. GENERAL MOTORSCase Example: Web Services • One GM executive believes that the Web Services architecture could be used to move GM from its supply-driven, build-to-stock business model to a demand-driven, build-to-order business model – an otherwise impossible feat. • To begin, GM first enhanced its supply-driven model by offering new functions via a Web Services architecture. • One Web Service is a locate-to-order service that dealers can use to easily find a specific car a customer might want in the inventory of other GM dealers

34. GENERAL MOTORSCase Example: Web Services cont. • Another Web Service is order-to-delivery which shortens the time to deliver a custom-ordered vehicle • Paving the way to eventually convert to a make to order business model • The ‘Rewards’?: • Cut its $25B inventory in half • Potentially shave $1,000 off the cost of each vehicle

35. Defining the Overall IT Architecture • The intent of an IT architecture is to bring order to the otherwise chaotic world of information systems by defining a set of guidelines and standards, and then adhering to them. • Because the architecture needs to support how the company operates, it reflects the business strategy. • Furthermore = as business changes, the architecture needs to keep pace. • Chief Technology Officer

36. An Enterprise Architecture Framework • To describe the IS architecture, look at the roles people and components play (5th edition Fig.5-12): • Rows: Views must be taken into account when building complex products: • planner (scope statement) • owner (model of the enterprise)

37. An Enterprise Architecture Framework Cont.. • Designer (model of the information system) • Builder (technology model). • Subcontractor (description of the components). • User (functioning system).

39. An Enterprise Architecture Framework cont. • Columns: • IS components: • Data models (what it is made of) • Functional models (how it works) • Network models (where the components are located) • Represent physical manifestations of the system.

40. An Enterprise Architecture Framework cont.. • Also: • People (who) • Time (when) • Motivation (why)

41. An Enterprise Architecture Framework cont.. • Use of the framework: When IS users bring in a package that follows a data model inconsistent with the rules of the company, a lot will be spent fixing the package. • Figure 5-13 - the ‘whole’ picture

43. FMC CORPORATIONCase Example: IT Architecture Development • When FMC split in two, it designed two new IT architectures • The architecture and technology director led five teams – for data, applications, integration, desktop, and platform • Each created a today architecture, a tomorrow architecture, and the “next minute” steps

44. FMC CORPORATIONCase Example: IT Architecture Development • The companies have now split and the tomorrow architecture has given FMC a standard that everyone agrees with, making standard-setting far easier • Now it is working on a new tomorrow architecture, for 2004-2005, when voice-over IP and Web Services kick in

45. THE SABRE SYSTEMCase Example: IT Architecture • When they looked at the underlying databases • Customer profiles, AAdvantage, NetSAAver • = found heaps of data redundancy (common!) leading to a huge redesign • American consolidated and linked these databases to have just one profile for each flyer.

46. THE SABRE SYSTEMCase Example: IT Architecture Cont.. • The architecture underlying American Airline’s Website is now modular • The ­existing SABRE computer reservation system serves as “the reservation service” module • Other modules perform the functions related to the Web • Due to this component-based architecture, it was fairly easy to add new functions

47. The Coming Architecture:Service–Oriented Architecture • Importance of an architecture is that it spells out the relationships between the components of an airplane, building, system etc. • In the past with IS these interactions have been ‘hard-coded’ point-to-point • Efficient but costly to maintain • Changing one component might require changing the others that interact with it

48. The Coming Architecture:Service–Oriented Architecture Cont.. • Relatively new system architecture moves away from this = Service Oriented Architecture (SOA) • Emergence parallels Web Services – uses the same architectural concept • Thinks about how to expose the data and functions in a way that other systems can easily use • Holy Grail? Which has long eluded IS organizations and addresses the need to be more agile

49. The IT Infrastructure- What is an IT Infrastructure? IT infrastructure is the foundation of an enterprise’s IT portfolio: • Provides the capability for reliable services and sharing • Includes both the technical and managerial expertise required to provide these services • Is linked to external industry infrastructure • Banking payments, airline reservations etc.

50. The IT Infrastructure- What is an IT Infrastructure? cont. • Shared characteristics differentiate an infrastructure from IT investments used by just one function • Elements can include: • Company-wide networks • Data warehouses • Large scale computing facilities • EDI capabilities • Applications ‘sit on top’ and directly support the business Vs. infrastructure ‘indirect’ support