Systems Analysis and Design, Tenth Edition End of Chapter Solutions CHAPTER 10 System Architecture

Systems Analysis and Design, Tenth Edition End of Chapter Solutions CHAPTER 10 System ArchitectureChapter Exercises s Questions 1. This chapter begins with an architecture checklist. If you had to rank the items, from ...

Systems Analysis and Design, Tenth Edition End of Chapter Solutions CHAPTER 10 System ArchitectureChapter Exercises s Questions 1. This chapter begins with an architecture checklist. If you had to rank the items, from most important to least important, what would your list look like? Explain your answer. Before selecting a system architecture, the analyst must consider the following issues:  Enterprise resource planning (ERP)  Initial cost and TCO  Scalability  Web integration  Legacy system interface requirements  Processing options  Security issues Student answers will vary with regard to ranking these items. Certainly the overall ERP is the framework within which everything else happens, so it should be at or very near the top. Cost and legacy interface requirements also are very important for a successful system. Of course, there is no one single answer. As with so many issues, the answer probably is “it depends.” This task might make a good topic for a class debate. (Page 404) 2. What is enterprise resource planning (ERP)? What is supply chain management (SCM)? Enterprise resource planning (ERP) defines a specific architecture, including standards for data, processing, network, and user interface design. It is important because it describes a specific hardware and software environment that ensures hardware connectivity and easy integration of future applications, including in-house software and commercial packages. ERP also can extend to suppliers and customers in a process called supply chain management. In a totally integrated supply chain, a customer order could cause a production planning system to schedule a work order, which in turn triggers a call for certain parts from one or more suppliers. (Page 406) 3. Suppose you had a client who never used a network. Explain, in everyday terms, the role of network servers and clients. A server is a computer that supplies data, processing services, or other support to one or more computers, called clients. Server-based processing allows users at remote locations to enter and access data from anywhere within the organization, regardless of where the centralized computer is located. Server-based processing is used in industries that require large amounts of data processing that can be done in batches at a central location. For example, a credit card company might run monthly statements in a batch, or a bank might use mainframe servers to update customer balances each night. A client is a stand-aloneSystems Analysis and Design, Tenth Edition Page 2 of 27 computer that allows the user to run application software locally. In client-based processing, an individual LAN client has a copy of the application program, but not the data, which is stored on a server. The client requests a copy of the data file from the server, and the server responds by transmitting the entire file to the client. After performing the processing, the client returns the data file to the server where it is stored. (Page 411–413) 4. Describe client/server architecture, including fat and thin clients, client/server tiers, and middleware.  Client/server architecture refers to systems that divide processing between one or more networked clients and a central server. In a typical client/server system, the client handles the entire user interface, including data entry, data query, and screen presentation logic. The server stores the data and provides data access and database management functions. Application logic is divided in some manner between the server and the clients.  A fat client design locates all or most of the application processing logic at the client. A thin client design locates all or most of the processing logic at the server. Typically, thin server designs provide better performance, because program code resides on the server, near the data. In contrast, a fat client handles more of the processing and must access and update the data more often. Fat client design is simpler and less expensive to develop, because the architecture resembles traditional file server designs where all processing is performed at the client.  Client/server designs can be two-tier or three-tier. In a two-tier design, the user interface resides on the client, all data resides on the server, and the application logic can run either on the server, on the client, or be divided between the client and the server. In a three-tier design, a middle layer between the client and server processes the client requests and translates them into data access commands that can be understood and carried out by the server.  Middleware is software that connects dissimilar applications and enables them to communicate and exchange data. (Pages 413-416) 5. Trace the history of system architecture, with particular emphasis on the impact of the personal computer and the Internet. Be sure to include examples. The Internet has had an enormous impact on system architecture. E-business trends are reshaping the corporate landscape as firms, large and small, learn how to harness the power of the Web and build efficient, reliable, and cost-effective business solutions. In proposing an e-commerce strategy, an IT group must consider in-house development of ebusiness systems, the availability of packaged solutions, and the design of corporate portals. The guidelines in Figure 10-17 on page 420 describe some key issues that a company must consider in planning an effective e-commerce strategy, and examples of Webbased systems development are shown in Figures 10-18, 19, 20, 21, and 22. (Pages 420- 424) 6. Is batch processing still relevant? Why or why not? As the chapter points out, batch processing is still with us after all these years. Batch processing was an acceptable choice in the 1960s, and for most firms, it was the only choice. Today, all businesses need real time information to operate, and batch processing is not usually practical. However, batch methods can be efficient and convenient in some situations. In some cases, where routine processing can be performed on a scheduled basis, batch processing still can be practical and cost-effective. For example, consider a firm that produces customer statements at the end of the month. A batch application might processSystems Analysis and Design, Tenth Edition Page 3 of 27 thousands of records in one run of the program. Batch programs can be scheduled to run at a predetermined time without user involvement. (Page 423) 7. Explain the difference between a LAN and a WAN. The difference between a LAN and WAN is in the area they cover. WANs cover great distances, whereas LANs are local. Topology means model, a topology of a network is a model of how a network is configured and arranged. Sketches should resemble their textbook versions; hierarchal, bus, ring, star. Wireless sketches should resemble their textbook versions; BSS, ESS, and ISS. Four IEEE amendments are:  802.11g, like a hybrid between a and b, fast speed (54Mbps) but 2.4 GHz spectrum. This is currently the most popular amendment.  802.11n offers speeds of 248 Mbps using MIMO technology.  MIMO relies on multiple data paths, also called multipath design, to increase bandwidth and range. (Page 412) 8. Define the term topology, and draw a sketch of each wired and wireless network topology. The way a network is configured is called the network topology. Topology can refer to a physical or a logical view of the network. For example, physical topology describes the actual network cabling and connections, while logical topology describes the way the components interact. It is important to understand the distinction, because a specific physical topology might be able to support more than one logical topology. For example, it is not uncommon to run cabling in a certain pattern because of physical installation and cost issues, but to use a different pattern for the logical topology. Make sure students understand that the workstations in Figure 10-23 are arranged in a circular shape, but that might or might not reflect the network topology. The examples shown in Figures 10-24 to 10-28 on pages 426 to 428 represent a logical topology, as seen by network users, who do not know or care about the physical cabling pattern. Student sketches should resemble those figures. (Pages 426-428) 9. Explain the main difference between the BSS and ESS wireless topologies. To what kind of wireless topology do the 802.16 standards apply?  BSS (Basic Service Set) consists of a single, central access point and wireless clients. BSS is also called infrastructure mode, and connects wireless clients to a wired infrastructure.  ESS (Extended Service Set) consists of multiple BSS networks connected together. ESS can cover a wide area and allows for roaming between access points.  The 802.16 standards define a MAN, Metropolitan Area Network. The 802.16 specifications are called WiMAX, and are expected to enable wireless multimedia applications with a range of up to 30 miles. (Pages 430-431) 10. List the sections of a system design specification, and describe the contents.  The system design specification consists of the following:  Executive (or Management) Summary: Provides a brief overview of the project for company managers and executives. Outlines the development efforts to date, current status report, summary of project costs to date and remaining costs, review of the overall benefits of the new system, presents the systems development phase schedule, and highlights any issues that management will need to address.  System Components: Contains the complete design for the new system, including user interface, outputs, inputs, files, databases, and network specifications. Also shouldSystems Analysis and Design, Tenth Edition Page 4 of 27 include source documents, report and screen layouts, DFDs, O-O diagrams, and all other relevant documentation.  System Environment: Describes the constraints, or conditions, affecting the system, including any requirements that involve operations, hardware, systems software, or security.  Implementation Requirements: Specifies start-up processing, initial data entry or acquisition, user training requirements, and software test plans.  Time and Cost Estimates: Detailed schedules, cost estimates, and staffing requirements for the systems development phase and revised projections for the remainder of the SDLC.  Appendices: Supplemental material, such as copies of documents from the first three phases, can be included if they would provide easy reference for readers. (Page 432) Discussion Topics 1. Information technology has advanced dramatically in recent years. At the same time, enormous changes in the business world have occurred as companies reflect global competition and more pressure for quality, speed, and customer service. Did the new technology inspire the business changes, or was it the other way around? Whether technology inspired business changes, or the other way around, is like a chickenand-egg question. Technology has opened up entire new areas that have had a profound effect on the way we do business. At the same time, competitive business pressures and a worldwide marketplace have spurred technology breakthroughs, and mass markets for digital products have brought new technology into the reach of most consumers. The answer to the question is not as important as the reasoning process that students use. 2. E­commerce has seen explosive growth in recent years. What are the most important reasons for this trend? Will it continue? Why or why not? While there are similarities, significant differences exist between B2C and B2B sectors. By its very nature, B2C requires powerful forms of marketing that can attract consumers and influence their buying habits and choices. Some consumers have embraced Internet-based shopping; others have been reluctant due to security and privacy concerns, among others. Also, some consumers are more comfortable in a face-to-face situation and prefer traditional business channels. None of these factors is critical in a B2B environment. To the contrary, businesses constantly are seeking to reduce costs, automate procedures, and improve ultimate quality. To achieve these goals, many firms have turned to B2B arrangements and participate in supply chain management systems, both as suppliers and business consumers. A good example might be a B2B inventory management system where speed and turnaround time are critical. Using computer-to-computer links with suppliers, the inventory system constantly can monitor stock items, sense usage trends, and signal vendors to increase stock levels automatically. The supplier responds by shipping additional inventory, the system reports the transaction, and the ongoing monitoring process continues to seek optimal stock levels, all without human intervention. 3. This chapter describes guidelines that a systems analyst can use when considering architecture. In your view, are all the items of equal weight and importance, or should some be ranked higher? Justify your position. There is no standard answer to this question. All the issues in the checklist on page 454 are important and can affect the project’s success. In a particular situation, one issue might beSystems Analysis and Design, Tenth Edition Page 5 of 27 placed at the top of the list because of specific priorities and concerns. If students feel that some items are of paramount importance, they should be encouraged to state their reasons and open up a discussion to see whether there is support for the viewpoint. 4. One manager states, “When a new system is proposed, I want a written report, not an oral presentation, which is like a sales pitch. I only want to see the facts about costs, benefits, and schedules.” Do you agree with that point of view? Arguments can be made both ways. For example, to support the manager’s point of view students might include the following:  An effective communicator must be able to build his or her case in writing as well as orally. If the manager has questions based on the written report, he or she always can call the systems analyst to get the questions answered.  Important written communications are permanent records that allow the information system project to be documented and tracked. As a systems analyst, you must include all arguments for and against your recommendation in your written report and not leave important arguments in reserve for your oral presentation.  Many managers make their decisions based on information and factors independent of the final management presentation. If that represents the decision-making style at a particular firm, then gathering a group of executives to hear the presentation might be a waste of productive time and money. Arguments in opposition to the manager’s point of view include the following:  When selecting from the many viable alternatives at the end of an SDLC phase, managers must weigh many conflicting tradeoffs among the alternatives. Executives often cannot make a clear-cut decision without the opportunity to discuss the alternatives at the final management presentation.  Information systems are built for the end users of an organization. Managers want assurances that the systems analysts are capable, knowledgeable, and able to support the users, and a presentation is an excellent means to evaluate the IT staff.  Managers often are busy traveling, mentoring, planning, negotiating, meeting, and so on, and have little time to read sizable, complicated, written reports. A face-to-face presentation improves the chances of a timely decision on the project. Projects 1. Visit the IT department at your school or a local company to learn about the network they use. Describe the network and draw a sketch of the configuration. Answers will vary, but students should be able to identify a network configuration as representing one of the basic network topologies described in the textbook. 2. Prepare a 10-minute talk explaining Web 2.0 and cloud computing to a college class. Using the text and your own Internet research, briefly describe the five most important points you will include in your presentation. Students should be able to use the information in the chapter, and add up-to-date Internet research on these trends. Part of the task is to list the key points, which would be a typical step in preparing a PowerPoint presentation to accompany the talk. 3. Perform research on the Internet to identify a service provider that offers Web-based business solutions, and write a brief memo describing the firm and its services.Systems Analysis and Design, Tenth Edition Page 6 of 27 Students should not have difficulty locating examples of ASPs that offer Web-based business solutions. ASPs are described in this chapter and in Chapter 7. An ASP provides applications, or access to applications, by charging a usage or subscription fee. Intershop, whose Web site is shown in Figure 10-18 on page 421, is an example of an ASP that can develop, maintain, and host a Web site. 4. Perform research on the Internet to learn about trends in wireless networking, and typical costs involved in the installation of a wireless LAN. Answers will vary, but certainly there is no lack of material on these topics. Encourage students to search for quality material, using the techniques described in Part D of the Systems Analyst’s Toolkit that follows Chapter 12.