No Plagiarism means quote every paraphase and annotation as well as not copying. Also try to avoid passive voice (grammarly helps with this common mistake). All work will be run through detection soft

CHAPTER 10 System
Architecture

Chapter 10 is the final chapter in the systems design phase of the SDLC. This chapter describes system architecture, which translates the logical design of an information system into a physical blueprint. As you plan the system architecture, you will learn about servers, clients, processing methods, networks, and related issues.

OBJECTIVES

When you finish this chapter, you will be able to:

• Provide a checklist of issues to consider when selecting a system architecture

• Trace the evolution of system architecture from mainframes to current designs

• Explain client/server architecture, including tiers, cost-benefit issues, and performance

• Compare in-house e-commerce development with packaged solutions and service providers

• Discuss the impact of cloud computing and Web 2.0

• Define network topology, including hierarchical, bus, ring, star, and mesh models

• Describe wireless networking, including wireless standards, topologies, and trends

• Describe the system design specification

INTRODUCTION

At this point in the SDLC, your objective is to determine an overall architecture to implement the information system. You learned in Chapter 1 that an information system requires hardware, software, data, procedures, and people to accomplish a specific set of functions. An effective system combines those elements into an architecture, or design, that is flexible, cost-effective, technically sound, and able to support the information needs of the business. This chapter covers a wide range of topics that support the overall system design, just as a plan for a new home would include a foundation plan, building methods, wiring and plumbing diagrams, traffic flows, and costs.

System architecture translates the logical design of an information system into a physical structure that includes hardware, software, network support, processing methods, and security. The end product of the systems design phase is the system design specification. If this document is approved, the next step is systems implementation.

PREVIEW CASE: Mountain View College Bookstore

Background: Wendy Lee, manager of college services at Mountain View College, wants a new information system that will improve efficiency and customer service at the three college bookstores.

In this part of the case, Tina Allen (systems analyst) and David Conroe (student intern) are talking about system architecture issues.

FIGURE 10-1 Typical system architecture tasks.

© Cengage Learning 2014

ARCHITECTURE CHECKLIST

Just as an architect begins a project with a list of the owner’s requirements, a systems analyst must approach system architecture with an overall checklist. Before making a decision, the analyst must consider several issues that will affect the architecture choice:

• Corporate organization and culture

• Enterprise resource planning (ERP)

• Initial and total cost of ownership (TCO)

• Scalability

• Web integration

• Legacy system interface requirements

• Processing options

• Security issues

• Corporate portals

Corporate Organization and Culture

To be successful, an information system must perform well in a company’s organization and culture. For example, consider two large bicycle brands, Green Bikes and Blue Bikes. Each firm has three operating divisions: an Asian subsidiary that manufactures the bicycles, a factory in Los Angeles that produces bike accessories and clothing, and a plant in Canada that makes bike carriers, racks, and custom trailers.

On the surface, the two firms are similar, but they have very different organizations and corporate cultures. Green Bikes is highly centralized, and oversees day-to-day operations from its Los Angeles office. Blue Bikes also has a Los Angeles executive office, but allows its three business units to operate separately, with minimal corporate oversight. Both firms are successful, and it is unlikely that their managerial styles will change anytime soon.

Suppose you were a consultant, and both firms asked you to suggest an IT architecture that would boost productivity and reduce costs. How would corporate organization and culture issues affect your recommendation? There is no easy answer to that question. The best approach probably would be to study day-to-day business functions, talk to users at all levels, and focus on operational feasibility issues, just as you did earlier in the development process.

Enterprise Resource Planning (ERP)

Many companies use enterprise resource planning (ERP) software, which was described in Chapter 1. The objective of ERP is to establish a company-wide strategy for using IT that includes a specific architecture, standards for data, processing, network, and user interface design. A main advantage of ERP is that it describes a specific hardware and software environment, also called a platform, that ensures connectivity and easy integration of future systems, including in-house software and commercial packages.

Even though ERP has been very popular, some argue that it is outdated because of major advances in technology. For example, in her CIO Magazine article shown in Figure 10-2, author Karen Goulart calls ERP an “old workhorse.” She suggests that ERP’s future success depends on integrating new technologies such as mobility and cloud computing, among others. In other words, an ERP designer might have to bring enterprise data, anytime, anywhere, to a smart phone in a sales rep’s pocket.

Many companies are extending internal ERP systems to their suppliers and customers, using a concept called supply chain management (SCM). For example, in a totally integrated supply chain system, a customer order could cause a manufacturing system to schedule a work order, which in turn triggers a call for more parts from one or more suppliers. In a dynamic, highly competitive economy, SCM can help companies achieve faster response, better customer service, and lower operating costs.

FIGURE 10-2 Is ERP outdated, or will it still be around? Author Karen Goulart says that ERP’s future success depends on integrating new technology, such as mobility and cloud computing.

© 2007–2012, TechTarget

Microsoft offers an enterprise solution called Microsoft Dynamics, as shown in Figure 10-3 on the next page. The interesting “test drive” video provides a scenario-based preview of how the software can integrate financial management, customer relationship management (CRM), supply chain management (SCM), and business metrics.

CASE IN POINT 10.1: ABC SYSTEMS

You are a systems analyst at ABC Systems, a fast-growing IT consulting firm that provides a wide range of services to companies that want to establish e-commerce operations. During the last 18 months, ABC acquired two smaller firms and set up a new division that specializes in supply chain management. Aligning ABC’s internal systems was quite a challenge, and top management was not especially happy with the integration cost or the timetable. To avoid future problems, you have decided to suggest an ERP strategy, and you plan to present your views at the staff meeting tomorrow. ABC’s management team is very informal and prefers a loose, flexible style of management. How will you persuade them that ERP is the way to go?

Initial Cost and TCO

You learned earlier about the importance of considering economic feasibility and TCO during systems planning and analysis. TCO includes tangible purchases, fees, and contracts called hard costs. However, additional soft costs of management, support, training, and downtime are just as important, but more difficult to measure.

Firms such as Micromation, which is shown in Figure 10-4 on page 409, offer specialized TCO analysis, benchmarks, and consulting. As the Micromation chart shows, user-related costs represent a very large slice of the total pie.

A TCO analysis should include the the following questions.

• If in-house development was selected as the best alternative initially, is it still the best choice? Is the necessary technical expertise available, and does the original cost estimate appear realistic?

• If a specific package was chosen initially, is it still the best choice? Are newer versions or competitive products available? Have any changes occurred in pricing or support?

• Have any new types of outsourcing become available?

FIGURE 10-3 Microsoft invites you to watch or take a scenario-based test drive of its Microsoft Dynamics product.

Screenshots used with permission from Microsoft.

• Have any economic, governmental, or regulatory events occurred that could affect the proposed project?

• Have any significant technical developments occurred that could affect the proposed project?

• Have any major assumptions changed since the company made the build versus buy decision?

• Are there any merger or acquisition issues to consider, whereby the company might require compatibility with a specific environment?

• Have any new trends occurred in the marketplace? Are new products or technologies on the verge of being introduced?

• Have you updated the original TCO estimate? If so, are there any significant differences?

FIGURE 10-4 The Micromation site suggests that soft costs are very significant, but are more difficult to measure.

© 2012 Micromation

The answers to these questions might affect the initial cost and TCO for the proposed system. You should review system requirements and alternatives now, before proceeding to design the system architecture.

Scalability

A network is composed of individual nodes. A node represents a physical device, wired or wireless, that can send, receive, or manage network data. For example, nodes can be servers, workstations, shared printers, mass storage devices, wireless access points, or mobile computers.

Scalability, also called extensibility, refers to a system’s ability to expand, change, or downsize easily to meet the changing needs of a business enterprise. Scalability is especially important in implementing systems that are volume-related, such as transaction processing systems. A scalable system is necessary to support a dynamic, growing business. For example, a scalable network could handle anywhere from a few dozen nodes to thousands of nodes, and a scalable DBMS could support the acquisition of an entire new sales division. When investing large amounts of money in a project, management is especially concerned about scalability issues that could affect the system’s life expectancy.

Web Integration

An information system includes applications, which are programs that handle the input, manage the processing logic, and provide the required output. The systems analyst must know if a new application will be part of an e-commerce strategy and the degree of integration with other Web-based components. As you learned earlier, a Web-centric architecture follows Internet design protocols and enables a company to integrate the new application into its e-commerce strategy. Even where e-commerce is not involved, a Web-centric application can run on the Internet or a company intranet or extranet. A Web-based application avoids many of the connectivity and compatibility problems that typically arise when different hardware environments are involved. In a Web-based environment, a firm’s external business partners can use standard Web browsers to import and export data.

Legacy Systems

A new system might have to interface with one or more legacy systems, which are older systems that use outdated technology, but still are functional. For example, a new marketing information system might need to report sales data to a server-based accounting system and obtain product cost data from a legacy manufacturing system.

Interfacing a new system with a legacy system involves analysis of data formats and compatibility. In some cases, a company will need to convert legacy file data, which can be an expensive and time-consuming process. Middleware, which is discussed later in this chapter, might be needed to pass data between new systems and legacy systems. Finally, to select the best architecture, the analyst must know if the new application eventually will replace the legacy system.

Processing Options

In planning the architecture, designers also must consider how the system will process data — online or in batches. For example, a high-capacity transaction processing system, such as an order entry system, requires more network, processing, and data storage resources than a monthly billing system that handles data in batches. Also, if the system must operate online, 24 hours a day and seven days a week (24/7), provision must be made for backup and speedy recovery in the event of system failure.

The characteristics of online and batch processing methods are described later in this chapter, with examples of each type.

Security Issues

From the password protection shown in Figure 10-5 to complex intrusion detection systems, security threats and defenses are a major concern to a systems analyst. As the physical design is translated into specific hardware and software, the analyst must consider security issues and determine how the company will address them. Security is especially important when data or processing is performed at remote locations, rather than at a centralized facility. In mission-critical systems, security issues will have a major impact on system architecture and design.

Web-based systems introduce additional security concerns, as critical data must be protected in the Internet environment. Also, firms that use e-commerce applications must assure customers that their personal data is safe and secure. System security concepts and strategies are discussed in detail in Chapter 12, Managing Systems Support and Security.

FIGURE 10-5 User IDs and passwords are important elements of system security.

© JMiks / Shutterstock.com

Corporate Portals

Depending on the system, the planned architecture might include a corporate portal. A portal is an entrance to a multifunction Web site. After entering a portal, a user can navigate to a destination using various tools and features provided by the portal designer. A corporate portal can provide access for customers, employees, suppliers, and the public. A well-designed portal can integrate with various other systems and provide a consistent look and feel.

SYSTEM ARCHITECTURE: THEN AND NOW

Every business information system must carry out three main functions:

• Manage applications that perform the processing logic.

• Handle data storage and access.

• Provide an interface that allows users to interact with the system.

Depending on the architecture, the three functions are performed on a server, on a client, or are divided between the server and the client. As you plan the design, you must determine where the functions will be carried out and the advantages and disadvantages of each design approach.

Mainframe Architecture

A server is a computer that supplies data, processing services, or other support to one or more computers, called clients. The earliest servers were mainframe computers, and a system design where the server performs all the processing sometimes is described as mainframe architecture. Although the actual server does not have to be a mainframe, the term mainframe architecture typically describes a multiuser environment where the server is significantly more powerful than the clients. A systems analyst should know the history of mainframe architecture to understand the server’s role in modern system design.

In the 1960s, mainframe architecture was the only choice. In addition to centralized data processing, the earliest systems performed all data input and output at a central location, often called a data processing center. Physical data was delivered or transmitted in some manner to the data processing center, where it was entered into the system. Users in the organization had no input or output capability, except for printed reports that were distributed by a corporate IT department.

As network technology advanced, companies installed terminals at remote locations, so that users could enter and access data from anywhere in the organization, regardless of where the centralized computer was located. A terminal included a keyboard and display screen to handle input and output, but lacked independent processing capability. In a centralized design, as shown in Figure 10-6, the remote user’s keystrokes are transmitted from his or her terminal to the mainframe, which responds by sending screen output back to the user’s screen.

Today, mainframe architecture still is used in industries that require large amounts of processing that can be done at a central location. For example, a bank might use mainframe servers to update customer balances each night. In a blend of old and new technology, an Internet-based retail operation might use mainframe architecture at a customer service center that fulfills its online sales as shown in Figure 10-7 on the next page.

FIGURE 10-6 In a centralized design, the remote user’s keystrokes are transmitted to the mainframe, which responds by sending screen output back to the user’s screen.

© Cengage Learning 2014

Impact of the Personal Computer

When PC technology exploded in the 1990s, powerful microcomputers quickly appeared on corporate desktops. Users found that they could run their own word processing, spreadsheet, and database applications, without assistance from the IT group, in a mode called stand-alone computing. Before long, companies linked the stand-alone computers into networks that enabled the user clients to exchange data and perform local processing.

When an individual user works in stand-alone mode, the workstation performs all the functions of a server by storing, accessing, and processing data, as well as providing a user interface. Although stand-alone PCs improved employee productivity and allowed users to perform tasks that previously required IT department assistance, stand-alone computing was inefficient and expensive. Even worse, maintaining data on individual workstations raised major concerns about data security, integrity, and consistency. Without a central storage location, it was impossible to protect and back up valuable business data, and companies were exposed to enormous risks. In some cases, users who were frustrated by a lack of support and services from the IT department created and managed their own databases. In addition to security concerns, this led to data inconsistency and unreliability.

FIGURE 10-7 Internet-based retail operations such as Amazon.com use customer service centers to fulfill online sales.

© Bloomberg via Getty Images

Network Evolution

As technology became available, companies resolved the problems of stand-alone computing by joining clients into a local area network (LAN) that allows sharing of data and hardware resources, as shown in Figure 10-8. One or more LANs, in turn, can connect to a centralized server. Further advances in technology made it possible to create powerful networks that could use satellite links, high-speed fiber-optic lines, or the Internet to share data.

A wide area network (WAN) spans long distances and can connect LANs that are continents apart, as shown in Figure 10-9. When a user accesses data on a LAN or WAN, the network is transparent because a user sees the data as if it were stored on his or her own workstation. Company-wide systems that connect one or more LANs or WANs are called distributed systems. The capabilities of a distributed system depend on the power and capacity of the underlying data communication network. Compared to mainframe architecture, distributed systems increase concerns about data security and integrity because many individual clients require access to perform processing.

FIGURE 10-8 A LAN allows sharing of data and hardware, such as printers and scanners.

© Cengage Learning 2014

CLIENT/SERVER DESIGNS

Today’s interconnected world requires an information architecture that spans the entire enterprise. Whether you are dealing with a departmental network or a multinational corporation, as a systems analyst you will work with a distributed computing strategy called client/server architecture.

FIGURE 10-9 A WAN can connect many LANs and link users who are continents apart.

© Cengage Learning 2014

Overview

Although no standard definition exists, the term client/server architecture generally 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. In a client/server interaction, the client submits a request for information from the server, which carries out the operation and responds to the client. As shown in Figure 10-10 the data file is not transferred from the server to the client — only the request and the result are transmitted across the network. To fulfill a request from a client, the server might contact other servers for data or processing support, but that process is transparent to the client. The analogy can be made to a restaurant where the customer gives an order to a server, who relays the request to a cook, who actually prepares the meal.

Figure 10-11 on the next page lists some major differences between client/server and traditional mainframe systems. Many early client/server systems did not produce expected savings because few clear standards existed, and development costs often were higher than anticipated. Implementation was expensive because clients needed powerful hardware and software to handle shared processing tasks. In addition, many companies had an installed base of data, called legacy data, which was difficult to access and transport to a client/server environment.

FIGURE 10-10 In a client/server design, data is stored and usually processed on the server.

© Cengage Learning 2014

As large-scale networks grew more powerful, client/server systems became more cost-effective. Many companies invested in client/server systems to achieve a unique combination of computing power, flexibility, and support for changing business operations. Today, client/server architecture is the dominant form of systems design, using Internet protocols and network models such as the ones described on pages 426–430. As businesses form new alliances with customers and suppliers, the client/server concept continues to expand to include clients and servers outside the organization.

Cloud computing, which is discussed later in this chapter, is seen by some observers as an entirely new concept. Others see it as the ultimate form of client/server architecture, where Internet-based computing becomes the server part of client/server and handles processing tasks, while the Internet itself becomes the platform that replaces traditional networks. The bottom line is that it doesn’t matter whether cloud computing is part of a client/server evolution, or a whole new way of thinking about computing. Either way, successful systems must support business requirements, and system architecture is an important step in the systems development process.

FIGURE 10-11 Comparison of the characteristics of client/server and mainframe systems.

© Cengage Learning 2014

The Client’s Role

The client/server relationship must specify how the processing will be divided between the client and the server. A fat client, also called a thick 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. What are the advantages and disadvantages of each design? Most IT experts agree that thin client 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. Compared with maintaining a central server, fat client TCO also is higher, because of initial hardware and software requirements and the ongoing expense of supporting and updating remote client computers. A fat client design, however, is simpler and less expensive to develop, because the architecture resembles traditional file server designs where all processing is performed at the client. Figure 10-12 compares the characteristics of fat and thin clients.

Client/Server Tiers

Early client/server designs were called two-tier designs. 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 or on the client, or be divided between the client and the server.

More recently, another form of client/server design, called a three-tier design, has become popular. In a three-tier design, the user interface runs on the client and the data is stored on the server, just as with a two-tier design. A three-tier design also has a middle layer between the client and server that processes the client requests and translates them into data access commands that can be understood and carried out by the server, as shown in Figure 10-13. You can think of the middle layer as an application server, because it provides the application logic, or business logic, required by the system. Three-tier designs also are called n-tier designs, to indicate that some designs use more than one intermediate layer.

FIGURE 10-12 Characteristics of fat and thin clients.

© Cengage Learning 2014

The advantage of the application logic layer is that a three-tier design enhances overall performance by reducing the data server’s workload. The separate application logic layer also relieves clients of complex processing tasks. Because it can run on a minicomputer that is much more powerful than the typical client workstations, the middle layer is more efficient and cost-effective in large-scale systems. Figure 10-14 on the next page shows where the data, the application logic, and the user interface are located on various architectures. In a client/server system, the tiers communicate using software called middleware, which is described in the following section.

FIGURE 10-13 Characteristics of two-tier versus three-tier client/server design.

© Cengage Learning 2014

Middleware

A recent Internet search for the phrase “What is Middleware” returned 80,500 sites. Unfortunately, the term middleware means different things to different people. So, what is middleware?

FIGURE 10-14 The location of the data, the application logic, and the user interface depend on the type of architecture.

© Cengage Learning 2014

In a multi-tier system, special software called middleware enables the tiers to communicate and pass data back and forth. Here are some other definitions you might encounter:

• Middleware offers an interface to connect software and hardware.

• Middleware can integrate legacy systems and Web-based applications. For example, when a user enters a customer number on a Web form, middleware can update a legacy accounting system.

• Middleware is like glue that holds different applications together.

• Middleware represents the slash in the term client/server.

• Middleware resembles the plumbing system in your home: it connects important objects in a way that requires little or attention.

The bottom line is that a hard and fast definition isn’t all that important. If you grasp the concept of middleware, you’ll be able to handle the development tools and learn the techniques required in your IT environment.

Cost-Benefit Issues

To support business requirements, information systems need to be scalable, powerful, and flexible. For most companies, client/server systems offer the best combination of features to meet those needs. Whether a business is expanding or downsizing, client/server systems enable the firm to scale the system in a rapidly changing environment. As the size of the business changes, it is easier to adjust the number of clients and the processing functions they perform than it is to alter the capability of a large-scale central server.

Client/server computing also allows companies to transfer applications from expensive mainframes to less-expensive client platforms. In addition, using common languages such as SQL, clients and servers can communicate across multiple platforms. That difference is important because many businesses have substantial investments in a variety of hardware and software environments.

Finally, client/server systems reduce network load and improve response times. For example, consider a user at a company headquarters who wants information about total sales figures. In a client/server system, the server locates the data, performs the necessary processing, and responds immediately to the client’s request. The data retrieval and processing functions are transparent to the client because they are done on the server, not the client.

Performance Issues

While it provides many advantages, client/server architecture does involve performance issues that relate to the separation of server-based data and networked clients that must access the data.

Consider the difference between client/server design and a centralized environment, where a server-based program issues a command that is executed by the server’s own CPU. Processing speed is enhanced because program instructions and data both travel on an internal system bus, which moves data more efficiently than an external network.

In contrast to the centralized system, a client/server design separates applications and data. Networked clients submit data requests to the server, which responds by sending data back to the clients. When the number of clients and the demand for services increases beyond a certain level, network capacity becomes a constraint, and system performance declines dramatically.

In the article shown in Figure 10-15, IBM states that the performance characteristics of a client/server system are not the same as a centralized processing environment. Client/server response times increase gradually as more requests are made, but then rise dramatically when the system nears its capacity. This point is called the knee of the curve, because it marks a sharp decline in the system’s speed and efficiency. To deliver and maintain acceptable performance, system developers must anticipate the number of users, network traffic, server size and location, and design a client/server architecture that can support current and future business needs.

What is the answer to enhancing client/server performance? According to IBM, client/server systems must be designed so the client contacts the server only when necessary and makes as few trips as possible.

Another issue that affects client/server performance is data storage. Just as processing can be done at various places, data can be stored in more than one location using a distributed database management system (DDBMS).

Using a DDBMS offers several advantages: Data stored closer to users can reduce network traffic; the system is scalable, so new data sites can be added without reworking the system design; and with data stored in various locations, the system is less likely to experience a catastrophic failure. A potential disadvantage of distributed data storage involves data security. It can be more difficult to maintain controls and standards when data is stored in various locations. In addition, the architecture of a DDBMS is more complex and difficult to manage. From a system design standpoint, the challenge is that companies often want it both ways — they want the control that comes with centralization and the flexibility associated with decentralization.

FIGURE 10-15 According to IBM, client/server response times increase gradually, and then rise dramatically when the system nears its capacity. That point is referred to as the knee of the curve.

© Copyright IBM Corporation 1994, 2012.

THE IMPACT OF THE INTERNET

The Internet has had an enormous impact on system architecture. The Internet has become more than a communication channel — many IT observers see it as a fundamentally different environment for system development.

Recall that in a traditional client/server system, the client handles the user interface, as shown in Figure 10-14 on the previous page, and the server (or servers in a multi-tier system) handles the data and application logic. In a sense, part of the system runs on the client, part on the server. In contrast, in an Internet-based architecture, in addition to data and application logic, the entire user interface is provided by the Web server in the form of HTML documents that are displayed by the client’s browser. Shifting the responsibility for the interface from the client to the server simplifies data transmission and results in lower hardware cost and complexity.

The advantages of Internet-based architecture have changed fundamental ideas about how computer systems should be designed, and we are moving rapidly to a total online environment. At the same time, millions of people are using Web-based collaboration and social networking applications to accomplish tasks that used to be done in person, over the phone, or by more traditional Internet channels. The following sections examine cloud computing and Web 2.0. It is important to understand these trends, which are shaping the IT industry’s future.

Cloud Computing

Cloud computing refers to the cloud symbol that often is used to represent the Internet. The cloud computing concept envisions a cloud of remote computers that provide a total online software and data environment that is hosted by third parties. For example, a user’s computer does not perform processing or computing tasks — the cloud does. This concept is in contrast to today’s computing model, which is based on networks that strategically distribute processing and data across the enterprise. In a sense, the cloud of computers acts as one giant computer that performs tasks for users.

Figure 10-16 shows users connected to the cloud, which performs the computing work. Instead of requiring specific hardware and software on the user’s computer, cloud computing spreads the workload to powerful remote systems that are part of the cloud. The user appears to be working on a local system, but all computing is actually performed in the cloud. No updates or maintenance are required of the user, and there are no compatibility issues.

Cloud computing effectively eliminates compatibility issues, because the Internet itself is the platform. This architecture also provides scaling on demand, which matches resources to needs at any given time. For example, during peak loads, additional cloud servers might come on line automatically to support the workload.

FIGURE 10-16 The explosive growth of cloud computing has attracted many firms that fight hard for market share.

© Cengage Learning 2014

Cloud computing is an ideal platform for powerful Software as a Service (SaaS) applications. As you learned in Chapter 7, SaaS is a popular deployment method where software is not purchased but is paid for as a service, much like one pays for electricity or cable TV each month. In this architecture, updates and changes to services can be easily made by service providers without involving the users.

Even though cloud computing has tremendous advantages, some concerns exist. First, cloud computing requires significantly more bandwidth (the amount of data that can be transferred in a fixed time period) than traditional client/server networks. Second, because cloud computing is Internet-based, if a user’s Internet connection becomes unavailable, he or she will be unable to access any cloud-based services. In addition, there are security concerns associated with sending large amounts of data over the Internet, as well as concerns about storing it securely. Finally, there is the issue of control. Because a service provider hosts the resources and manages data storage and access, the provider has complete control of the system. Many firms are wary of handing over control of mission-critical data and systems to a third-party provider.

Future technology advances will make cloud computing even more feasible, desirable, and secure. As the IT industry moves toward a Web-based architecture, cloud computing will be marketed aggressively and growth will be rapid. Figure 10-16 lists some of the major players in the cloud market. Although the list will change from month to month, or week to week, one thing will not change: cloud computing will be a cornerstone of IT growth in the coming decade.

Web 2.0

The shift to Internet-based collaboration has been so powerful and compelling that it has been named Web 2.0. Web 2.0 is not a reference to a more technically advanced version of the current Web. Rather, Web 2.0 envisions a second generation of the Web that will enable people to collaborate, interact, and share information more dynamically.

Leading Web 2.0 author Tim O’Reilly has suggested that the strong interest in Web 2.0 is driven by the concept of the Internet as a platform. O’Reilly sees future Web 2.0 applications delivering software as a continuous service with no limitations on the number of users that can connect or how users can consume, modify, and exchange data.

Social networking sites, such as Facebook, Twitter, and LinkedIn are seeing explosive growth in the Web 2.0 environment. Another form of social collaboration is called a wiki. A wiki is a Web-based repository of information that anyone can access, contribute to, or modify. In a sense, a wiki represents the collective knowledge of a group of people. One of the best-known wikis is Wikipedia.org, but smaller-scale wikis are growing rapidly at businesses, schools, and other organizations that want to compile and share information.

One of the goals of Web 2.0 is to enhance creativity, interaction, and shared ideas. In this regard, the Web 2.0 concept resembles the agile development process and the open-source software movement. Web 2.0 communities and services are based on a body of data created by users. As users collaborate, new layers of information are added in an overall environment known as the Internet operating system. These layers can contain text, sound bytes, images, and video clips that are shared with the user community.

E-COMMERCE ARCHITECTURE

The huge expansion of Web-based commerce is reshaping the IT landscape. Internet business solutions must be efficient, reliable, and cost-effective. When planning an e-commerce architecture, analysts can examine in-house development, packaged solutions, and service providers. The following sections discuss these options.

In-House Solutions

In Chapter 7, you learned how to analyze advantages and disadvantages of in-house development versus purchasing a software package. The same basic principles apply to system design.

If you decide to proceed with an in-house solution, you must have an overall plan to help achieve your goals. How should you begin? Figure 10-17 offers guidelines for companies developing e-commerce strategies. An in-house solution usually requires a greater initial investment, but provides more flexibility for a company that must adapt quickly in a dynamic e-commerce environment. By working in-house, a company has more freedom to integrate with customers and suppliers and is less dependent on vendor-specific solutions.

FIGURE 10-17 Guidelines for companies developing e-commerce strategies.

© Cengage Learning 2014

For smaller companies, the decision about in-house Web development is even more critical, because this approach will require financial resources and management attention that many small companies might be unable or unwilling to commit. An in-house strategy, however, can provide valuable benefits, including the following:

• A unique Web site, with a look and feel consistent with the company’s other marketing efforts

• Complete control over the organization of the site, the number of pages, and the size of the files

• A scalable structure to handle increases in sales and product offerings in the future

• More flexibility to modify and manage the site as the company changes

• The opportunity to integrate the firm’s Web-based business systems with its other information systems, creating the potential for more savings and better customer service

Whether a firm uses an in-house or a packaged design, the decision about Web hosting is a separate issue. Although internal hosting has some advantages, such as greater control and security, the expense would be much greater, especially for a small- to medium-sized firm.

CASE IN POINT 10.2: SMALL POTATOES, INC.

Small Potatoes is a family-operated seed business that has grown rapidly. Small Potatoes specializes in supplying home gardeners with the finest seeds and gardening supplies. Until now, the firm has done all its business by placing ads in gardening and health magazines, and taking orders using a toll-free telephone number.

Now, the family has decided to establish a Web site and sell online, but there is some disagreement about the best way to proceed. Some say it would be better to develop the site on their own, and Betty Lou Jones, a recent computer science graduate, believes she can handle the task. Others, including Sam Jones, Betty’s grandfather, feel it would be better to outsource the site and focus on the business itself. Suppose the family asked for your opinion. What would you say? What additional questions would you ask?

FIGURE 10-18 Intershop offers software solutions for smaller companies that want to get an e-business up and running quickly.

© 2009–2012 Intershop Communications AG

Packaged Solutions

If a small company is reluctant to take on the challenge and complexity of developing an Internet commerce site in-house, an alternative can be a packaged solution. This is true even for medium- to large-sized firms. Many vendors, including Microsoft and Intershop, offer turnkey systems for companies that want to get an e-business up and running quickly, as shown in Figure 10-18.

For large-scale systems that must integrate with existing applications, packaged solutions might be less attractive.

Service Providers

Another alternative is to use an application service provider (ASP). As explained in Chapter 7, an ASP provides applications, or access to applications, by charging a usage or subscription fee. Today, many ASPs offer full-scale Internet business services for companies that decide to outsource those functions.

managed hosting, which also was discussed in Chapter 7. As shown in Figure 10-19 on the next page,

Another service provider option is managed hosting, which also was discussed in Chapter 7. As shown in Figure 10-19 on the next page, a solution provider such as Rackspace can host and maintain a corporate Web site. Rackspace states that its customers will “never have to implement, update, troubleshoot, patch, monitor, administer, backup data, or worry again.”

A systems analyst confronts a bewildering array of products and strategies when implementing Internet-based systems. A good starting point might be to consider the experience of other companies in the same industry. Many firms offer the names of clients and customers, along with their success stories. Although this information might or might not be reliable, it can provide valuable knowledge regarding a vendor’s products and services.

PROCESSING METHODS

In selecting an architecture, the systems analyst must determine which transactions will be handled online, and what functions, if any, can be carried out using a batch processing method.

FIGURE 10-19 Rackspace offers managed hosting and a variety of cloud-based services.

© 2012 Rackspace, US Inc.

Online Processing

Early computer systems were designed to handle data records as a group, or batch. Few, if any systems use that model today. However, even the most advanced online systems must perform maintenance, post large quantities of data during off-hours when network traffic is low, and carry out housekeeping tasks just as their legacy computer ancestors did. This section will discuss the online processing capability that is at the core of powerful, modern systems, and the following section will describe the evolution of batch processing.

An online system handles transactions when and where they occur and provides output directly to users. Because it is interactive, online processing avoids delays and allows a constant dialog between the user and the system.

An airline reservations system is a familiar example of online processing. When an online customer visits the airline’s Web site, he or she can enter the origin, destination, travel dates, and travel times. The system searches a database and responds by displaying available flights, times, and prices. The customer can make a reservation, enter a name, address, credit card information, and other required data and the system creates the reservation, assigns a seat, and updates the flight database immediately.

Online processing also can be used with file-oriented systems. Figure 10-20 shows what happens when a customer uses an ATM to inquire about an account balance. After the ATM verifies the customer’s card and password, the customer enters the request (Step 1). Then, the system accesses the account master file using the account number as the primary key and retrieves the customer’s record (Step 2). The system verifies the account number and displays the balance (Step 3). Data is retrieved and the system transmits the current balance to the ATM, which prints it for the customer. Online processing systems have four typical characteristics:

1. The system processes transactions completely when and where they occur.

2. Users interact directly with the information system.

3. Users can access data randomly.

4. The information system must be available whenever necessary to support business functions.

Batch Processing: Still With Us After All These Years

Batch processing means that data is managed in groups, or batches. That was an acceptable choice in the 1960s, and for most firms, it was the only choice. Today, all businesses need realtime information to operate, and batch processing is not practical. However, batch methods can be efficient and convenient in some situations.

For example, batch processing can be used for large amounts of data that must be processed on a routine schedule, such as weekly paychecks, daily credit card transaction updates, or closing stock data that must be calculated and published in the following day’s news media. The main advantages of batch methods are:

FIGURE 10-20 When a customer requests a balance, the ATM system verifies the account number, submits the query, retrieves the current balance, and displays the balance on the ATM screen.

© Cengage learning 2014

• Tasks can be planned and run on a predetermined schedule, without user involvement.

• Batch programs that require major network resources can run at times when costs, and impact on other traffic, will be lowest.

• A batch method is well-suited to address security, audit, and privacy concerns, because it runs in a relatively controlled environment.

Real-World Examples

Figure 10-21 shows a familiar point-of-sale (POS) terminal in a supermarket chain. The diagram in Figure 10-22 on the next page shows how that POS terminal might trigger a series of online and batch processing events. Notice that the system uses online processing to handle data entry and inventory updates, while reports and accounting entries are performed in a batch. Why would any company choose a mix of online and batch processing? The answer is that it makes good business sense. Consider the following scenario in a typical retail store:

FIGURE 10-21 Retail point-of-sale terminals provide customer sales support and transaction processing capability.

© Karlheinz Schindler/dpa/Landov

• During business hours, a salesperson enters a sale on a POS terminal, which is part of an online system that handles daily sales transactions and maintains an up-to-date inventory file.

• When the salesperson enters the transaction, online processing occurs. The system performs calculations, updates the inventory file, and produces output on the POS terminal in the form of a screen display and a printed receipt. At the same time, each sales transaction creates input data for day-end batch processing.

• When the store closes, the system uses the sales transactions to produce the daily sales report, perform the related accounting entries, and analyze the data to identify slow or fast-moving items, sales trends, and related issues — such as store discounts for the next day.

FIGURE 10-22 Many retailers use a combination of online and batch processing. When a salesperson enters the sale on the POS terminal, the online system retrieves data from the item file, updates the quantity in stock, and produces a sales transaction record. At the end of the day, a batch processing program produces a daily sales report and updates the accounting system.

© Cengage Learning 2014

Which method is better, online or batch processing? The answer is neither — they are totally different, but can work well together. In this scenario, an online system handles point-of-sale processing, which must be done as it occurs, while a batch method provides routine, overnight processing and marketing analysis. Online processing allows the data to be entered and validated immediately, so the information always is up to date. However, a heavy volume of online transactions can be expensive for smaller firms, and data backup and recovery also adds to IT costs. In contrast, when used properly, batch processing can be cost-effective and less vulnerable to system disruption.

CASE IN POINT 10.3: R/WAY TRUCKING COMPANY

You are the new IT manager at R/Way, a small but rapidly growing trucking company headquartered in Cleveland, Ohio. The company slogan is “Ship It R/Way — State-of-the-Art in Trucking and Customer Service.” R/Way’s information system currently consists of a file server and three workstations where freight clerks enter data, track shipments, and prepare freight bills. To perform their work, the clerks obtain data from the server and use database and spreadsheet programs stored on their PCs to process the data.

Unfortunately, your predecessor did not design a relational database. Instead, data is stored in several files, including one for shippers, one for customers, and one for shipments. The system worked well for several years, but cannot handle current volume or support online links for R/Way shippers and customers. The company president is willing to make changes, but he is reluctant to spend money on major IT improvements unless you can convince him that they are necessary.

What would you recommend and why?

NETWORK MODELS

A network allows the sharing of hardware, software, and data resources in order to reduce expenses and provide more capability to users. When planning a network design, you must consider network terms and concepts, including the OSI model, network modeling tools, network topology, network protocols, and wireless networks, which are covered in this section. Other important issues, such as network performance and security, are covered in Chapter 12, Managing Systems Support and Security.

The OSI Model

Based on the discussion of system architecture earlier in this chapter, you already understand basic network terms such as client, server, LAN, WAN, client/server architecture, tiers, middleware, and cloud computing.

Before you study network topology, you should be aware of the OSI (Open Systems Interconnection) model, which describes how data moves from an application on one computer to an application on another networked computer. The OSI model consists of seven layers, and each layer performs a specific function.

The OSI model provides physical design standards that assure seamless network connectivity, regardless of the specific hardware environment. If you took a networking course, you probably studied the OSI model in detail. As an IT professional, if your tasks include network installation, configuration, and maintenance, you will need additional resources and information about the OSI model.

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.

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.

LAN and WAN networks typically are arranged in four patterns: hierarchical, bus, ring, and star. The concepts are the same regardless of the size of the network, but the physical implementation is different for a large-scale WAN that spans an entire business enterprise compared with a small LAN in a single department. The four topologies are described in the following sections.

FIGURE 10-23 Although these workstations form a circle physically, the layout has no bearing on the network topology, which might be a bus, ring, star, or other logical design.

© Patrick Seeger/dpa /Landov

HIERARCHICAL NETWORK   In a hierarchical network, as shown in Figure 10-24 on the next page, one or more powerful servers control the entire network. Departmental servers control lower levels of processing and network devices. An example of a hierarchical network might be a retail clothing chain, with a central computer that stores data about sales activity and inventory levels and local computers that handle store-level operations. The stores transmit data to the central computer, which analyzes sales trends, determines optimum stock levels, and coordinates a supply chain management system. In this situation, a hierarchical network might be used, because it mirrors the actual operational flow in the organization.

FIGURE 10-24 A hierarchical network with a single server that controls the network.

© Cengage Learning 2014

One disadvantage of a hierarchical network is that if a business adds additional processing levels, the network becomes more complex and expensive to operate and maintain. Hierarchical networks were often used in traditional mainframe-based systems, but are much less common today.

BUS NETWORK   In a bus network, as shown in Figure 10-25, a single communication path connects the central server, departmental servers, workstations, and peripheral devices. Information is transmitted in either direction between networked devices, and all messages travel over the same central bus. Bus networks require less cabling than other topologies, because only a single cable is used. Devices can also be attached or detached from the network at any point without disturbing the rest of the network. In addition, a failure in one workstation on the network does not necessarily affect other workstations on the network.

One major disadvantage of a bus network is that if the central bus becomes damaged or defective, the entire network shuts down. Another disadvantage is that overall performance declines as more users and devices are added, because all message traffic must flow along the central bus. This does not occur in the treelike structure of a hierarchical network or the hub-and-spoke design of a star network, where network paths are more isolated and independent.

The bus network is one of the oldest LAN topologies, and is a simple way to connect multiple workstations. Before the proliferation of star networks, bus networks were very common. Today, the bus design is much less popular, but some firms have retained bus networks to avoid the expense of new wiring and hardware.

RING NETWORK   Although ring networks are still around, they are somewhat outdated. IBM was a leader in ring network technology, and large companies who use IBM mainframe equipment still deploy the ring network design. A ring network, as shown in Figure 10-26, resembles a circle where the data flows in only one direction from one device to the next. In function, a ring network can be thought of as a bus network with the ends connected. One disadvantage of a ring network is that if a network device (such as a PC or a server) fails, the devices downstream from the failed device cannot communicate with the network.

FIGURE 10-25 A bus network with all devices connected to a single communication path.

© Cengage Learning 2014

STAR NETWORK   Because of its speed and versatility, the star network is by far the most popular LAN topology today. A star network has a central networking device called a switch, which manages the network and acts as a communications conduit for all network traffic. In the past, a device known as a hub was used to connect star networks, but a switch offers advanced technology and much better performance. A hub or switch functions like a familiar multi-socket power strip, but with network devices such as servers, workstations, and printers plugged in rather than electrical appliances. The hub broadcasts network traffic, called data frames, to all connected devices. In contrast, a switch enhances network performance by sending traffic only to specific network devices that need to receive the data.

A star configuration, as shown in Figure 10-27 on the next page, provides a high degree of network control, because all traffic flows into and out of the switch. An inherent disadvantage of the star design is that the entire network is dependent on the switch. However, in most large star networks, backup switches are available immediately in case of hardware failure.

FIGURE 10-26 A ring network with a set of computers that send and receive data flowing in one direction.

© Cengage Learning 2014

MESH NETWORK   In the mesh network shown in Figure 10-28 on the next page, each node connects to every other node. While this design is extremely reliable, it also is very expensive to install and maintain. A mesh network resembles the Internet in that a message can travel on more than one path. Originally developed for military applications, the primary advantage of a mesh network is redundancy, because multiple paths provide backup if communication problems arise or some nodes become inoperable.

FIGURE 10-27 A typical star network with a switch, departmental server, and connected workstations.

© Cengage Learning 2014

FIGURE 10-28 Mesh networks are used in situations where a high degree of redundancy is needed, such as military applications. The redundant design provides alternate data paths, but is expensive to install and maintain.

© Cengage Learning 2014

Network Devices

Networks such as LANs or WANs can be interconnected using devices called routers. A router is a device that connects network segments, determines the most efficient data path, and guides the flow of data.

FIGURE 10-29 Routers can be used to connect LANs and WANs to other networks, such as the Internet.

© Cengage Learning 2014

Using a router, any network topology can connect to a larger, dissimilar network, such as the Internet. This connection is called a gateway. The example in Figure 10-29 shows a star topology, where a switch connects nodes in the LAN and the router links the network to the Internet. A device called a proxy server provides Internet connectivity for internal LAN users. The vast majority of business networks use routers to integrate the overall network architecture.

Modeling Tools

As you translate a network model into a physical version of the system, you can use software tools, such as Microsoft Visio, which is a multipurpose drawing tool, to represent the physical structure and network components. Visio offers a wide variety of drawing types, styles, and downloadable templates, as shown in Figure 10-30.

  TOOLKIT TIME

The CASE Tools in Part B of the Systems Analyst’s Toolkit can help you document business functions and processes, develop graphical models, and provide an overall framework for information system development. To learn more about these tools, turn to Part B of the four-part Toolkit that follows Chapter 12.

FIGURE 10-30 Visio offers many network templates that users can download free.

Screenshots used with permission from Microsoft.

WIRELESS NETWORKS

Although a wired LAN provides enormous flexibility, the cabling cost can be substantial, as well as the inevitable wiring changes that occur in a dynamic organization. Many companies find wireless technology to be an attractive alternative. A wireless local area network, or WLAN, is relatively inexpensive to install and is well-suited to workgroups and users who are not anchored to a specific desk or location. Most notebook computers are equipped with built-in wireless capability, and it is relatively simple to add this feature to existing desktop computers and workstations in order to set up a wireless network.

Like their wired counterparts, wireless networks have certain standards and topologies, which are discussed in the following sections.

Wireless Network Standards

Wireless networks are based on various standards and protocols that still are evolving. The most popular of these is called IEEE 802.11, which is a family of standards developed by the Institute of Electrical and Electronics Engineers (IEEE) for wireless LANs.

Current wireless networks are based on variations of the original 802.11 standard. Several versions, or amendments, were intended to improve bandwidth, range, and security. The table in Figure 10-31 contains a brief comparison of the IEEE 802.11 amendments. Note that speed is measured in Mbps (megabits per second) or Gbps (gigabits per second).

Early IEEE 802.11 standards had limited transmission capacity and were not popular. Later versions, such as 802.11g, offered increased bandwidth and were widely accepted by the IT industry. The more recent 802.11n uses multiple input/multiple output (MIMO) technology to boost performance. MIMO relies on multiple data paths, also called multipath design, to increase bandwidth and range. The latest proposed standards, 802.11ac and 802.11ad, are currently being tested. If wireless capacity continues to expand and security issues can be overcome, WLANs could replace wired networks in many situations. Wireless security is discussed in detail in Chapter 12, Managing Systems Support and Security.

Wireless Network Topologies

Like wired networks, wireless networks also can be arranged in different topologies. The two most common network topologies available for IEEE 802.11 WLANs are the Basic Service Set and the Extended Service Set Figure 10-32 shows simplified models of these topologies.

FIGURE 10-31 IEEE Wi-Fi standards and characteristics.

© Cengage Learning 2014

The Basic Service Set (BSS), also called the infrastructure mode, is shown at the top of Figure 10-32. In this configuration, a central wireless device called an access point or wireless access point (WAP), is used to serve all wireless clients. The access point is similar to a hub in the LAN star topology, except it provides network services to wireless clients instead of wired clients. Because access points use a single communications medium, the air, they broadcast all traffic to all clients, just as a hub would do in a wired network. Typically, the access point itself is connected to a wired network, so wireless clients can access the wired network.

The second wireless topology is the Extended Service Set (ESS), as shown at the bottom of Figure 10-32. An Extended Service Set is made up of two or more Basic Service Set networks. Thus, using an ESS topology, wireless access can be expanded over a larger area. Each access point provides wireless services over a limited range. As a client moves away from one access point and closer to another, a process called roaming automatically allows the client to associate with the stronger access point, allowing for undisrupted service.

FIGURE 10-32 Notice that the user in the upper screen has moved out of the BSS coverage area, and cannot communicate. In the lower screen, the user roams into another ESS coverage area, and the transition is seamless.

© Cengage Learning 2014

Wireless Trends

Wireless technology has brought explosive change to the IT industry, and will continue to affect businesses, individuals, and society. Even in the ever-changing world of IT, it would be difficult to find a more dynamic area than wireless technology.

With the growing popularity of 802.11, many firms offer networking products, services, and information. One of the most significant groups is the Wi-Fi Alliance, which maintains a Web site at www.wi-fi.org. According to the site, the Alliance is a nonprofit international association formed in 1999 to certify interoperability of wireless network products based on IEEE 802.11 specifications. Products that meet the requirements are certified as Wi-Fi (wireless fidelity) compatible. Currently the Wi-Fi Alliance has over 500 member companies from around the world, and over 9,000 products have received Wi-Fi certification. The stated goal of the Wi-Fi Alliance is to enhance the user experience through product interoperability.

Even though they have many advantages, wireless networks also have limitations and disadvantages. For example, devices that use the 2.4 GHz band can pick up interference from appliances such as microwave ovens and cordless telephones that use the same band. More important, wireless networks pose major security concerns because wireless transmissions are much more susceptible to interception and intrusion than wired networks. These issues are discussed in detail in Chapter 12, Managing Systems Support and Security.

In addition to Wi-Fi, another form of wireless transmission called Bluetooth is very popular for short-distance wireless communication that does not require high power. Examples of Bluetooth devices include wireless keyboards, mice, printers, cell phone headsets, and digital cameras, among others. People with Bluetooth-equipped phones or PDAs can even beam information to each other and exchange digital notes.

Although the expansion of Wi-Fi has been dramatic, future technology promises even greater wireless speed, range, and compatibility. For example, in addition to 802.11 protocols for LANs, IEEE is working on 802.16 standards, sometimes called WiMAX, which are broadband wireless communications protocols for MANs (metropolitan area networks).

CASE IN POINT 10.4: SPIDER IT SERVICES

Spider IT Services specializes in custom network design and installation. Firms hire Spider to do an overall analysis of their network needs, including a detailed cost-benefit study. Recently, a problem arose. One of Spider’s clients complained that the relatively new network was too slow and lacked sufficient capacity. Reviewing the case, Spider’s top management realized that the rapidly growing client had simply outgrown the network much earlier than anticipated.

Could this problem have been avoided? Note that IBM, in the article shown in Figure 10-15 on page 417, commented that performance can “degrade exponentially” in certain kinds of network situations. Consider the IBM article and other material in this chapter, and offer your views.

SYSTEMS DESIGN COMPLETION

System architecture marks the end of the systems design phase of the SDLC. Recall that back in the systems analysis phase, all functional primitives were identified and documented with process descriptions. The objective then was to identify the system’s functions and determine what each logical module would do, without attempting to determine how that function would be carried out. Moving from analysis to design tasks, the development process continued with consideration of output and user interface design, data design, and system architecture issues. Now, based on a clear definition of system requirements and design, software applications can be developed, documented, and tested as part of the systems implementation phase of the SDLC, which is described in Chapter 11, Managing System Implementation.

Developers must also consider system management and support tools that can monitor system performance, deal with fault management, handle backup, and provide for disaster recovery. These topics are covered in detail in Chapter 12, Managing Systems Support and Security.

The final activities in the systems design phase are preparing a system design specification, obtaining user approval, and delivering a presentation to management.

System Design Specification

The system design specification is a document that presents the complete design for the new information system, along with detailed costs, staffing, and scheduling for completing the next SDLC phase — systems implementation.

The system design specification is the baseline against which the operational system will be measured. Unlike the system requirements document, which is written for users to understand, the system design specification is oriented toward the programmers who will use it to create the necessary programs. Some sections of the system requirements document are repeated in the system design specification, such as process descriptions, data dictionary entries, and data flow diagrams.

The system design specification varies in length, so you must organize it carefully and number all pages in sequence. You should include a cover page, a detailed table of contents, and an index. The contents of the system design specification depend on company standards and the complexity of the system. A typical system design specification typically includes the following sections.

1. Management Summary. This is a brief overview of the project for company managers and executives. It outlines the development efforts to date, provides a current status report, summarizes project costs, reviews the benefits of the new system, presents the systems implementation schedule, and highlights any issues that management will need to address.

2. System Components. This section contains the complete design for the new system, including the user interface, outputs, inputs, files, databases, and network specifications. You should include source documents, report and screen layouts, DFDs, and all other relevant documentation. You also should include the requirements for all support processing, such as backup and recovery, start-up processing, and file retention. If the purchase of a software package is part of the strategy, you must include any interface information required between the package and the system you are developing. If you use a CASE design tool, you can print design diagrams and most other documentation directly from the tool.

3. System Environment. This section describes the constraints, or conditions, affecting the system, including any requirements that involve operations, hardware, systems software, or security. Examples of operational constraints include transaction volumes that must be supported, data storage requirements, processing schedules, reporting deadlines, and online response times.

4. Implementation Requirements. In this section, you specify start-up processing, initial data entry or acquisition, user training requirements, and software test plans.

5. Time and Cost Estimates. This section provides detailed schedules, cost estimates, and staffing requirements for the systems development phase and revised projections for the remainder of the SDLC. You also present total costs-to-date for the project and compare those costs with your prior estimates.

6. Additional Material. Other material can be included at the end of the system design specification. In this section, you might insert documents from earlier phases if they would be helpful to readers.

User Approval

Users must review and approve the interface design, report and menu designs, data entry screens, source documents, and other areas of the system that affect them. The review and approval process continues throughout the systems design phase. When you complete the design for a report, you should meet with users to review the prototype, adjust the design if necessary, and obtain written approval. Chapter 8 contains guidelines and suggestions about report design.

Securing approvals from users throughout the design phase is very important. That approach ensures that you do not have a major task of obtaining approvals at the end, it keeps the users involved with the system’s development, and it gives you feedback about whether or not you are on target. Some sections of the system design specification might not interest users, but anything that does affect them should be approved as early as possible.

Other IT department members also need to review the system design specification. IT management will be concerned with staffing, costs, hardware and systems software requirements, network impact, and the effect on the operating environment when the new system is added. The programming team will want to get ready for its role, and the operations group will be interested in processing support, report distribution, network loads, integration with other systems, and any hardware or software issues for which they need to prepare. You must be a good communicator to keep people up to date, obtain their input and suggestions, and obtain necessary approvals.

When the system design specification is complete, you distribute the document to a target group of users, IT department personnel, and company management. You should distribute the document at least one week before your presentation to allow the recipients enough time to review the material.

Presentations

Usually, you will give several presentations at the end of the systems design phase. The presentations give you an opportunity to explain the system, answer questions, consider comments, and secure final approval. Part A of the Systems Analyst’s Toolkit can provide valuable guidelines and tips about oral presentations.

  TOOLKIT TIME

The Communication Tools in Part A of the Systems Analyst’s Toolkit can help you develop better reports and presentations. To learn more about these tools, turn to Part A of the four-part Toolkit that follows Chapter 12.

The first presentation is to the systems analysts, programmers, and technical support staff members who will be involved in future project phases or operational support for the system. Because of the audience, the presentation is technically oriented.

Your next presentation is to department managers and users from departments affected by the system. As in the first presentation, your primary objective is to obtain support and approval for the systems design. This is not a technical presentation; it is aimed at user interaction with the system and management’s interest in budgets, schedules, staffing, and impact on the production environment.

The final presentation is delivered to management. By the time you give this presentation, you should have obtained all necessary approvals from prior presentations, and you should have the support of users and the IT department. Just like the management presentation at the end of the systems analysis phase, this presentation has a key objective: to obtain management’s approval and support for the next development step — systems implementation — including a solid commitment for financial and other resources needed.

Based on the presentation and the data you submitted, management might reach one of three decisions: proceed with systems development, perform additional work on the systems design phase, or terminate the project.

A QUESTION OF ETHICS

© faberfoto_it/iStockphoto

The new accounting system is operational, but feedback from users has been negative. The most common complaint is that the system is not user-friendly. Some people in the IT department think that more user training would solve the problem. However, Sam, the IT manager, is opposed to a fresh round of training.”Let’s just set up the network to monitor the users’ keystrokes and mouse clicks, and see what the patterns are,” he suggested.” We can analyze the data and come up with tips and suggestions that would make the system easier to use.”

Your initial reaction is that Sam is wrong, for two reasons. First, you believe that monitoring would not be an effective method to learn what users really want. In your view, that should have been done in the system requirements phase. Second, you are bothered by an ethical question: Even though the proposed monitoring would involve company business, the company network, and company time, you feel that many users would resent the unannounced monitoring, and might feel that their performance or other computing activities were being appraised without their knowledge.

Sam has asked to you to write up a recommendation. What will you say about the ethical question that troubles you?

CHAPTER SUMMARY

An information system combines hardware, software, data, procedures, and people into a system architecture. The architecture translates the system’s logical design into a physical structure that includes hardware, software, and processing methods. The software consists of application programs, also called applications, that handle the input, manage the processing logic, and provide the required output.

Before selecting an architecture, the analyst must consider enterprise resource planning, initial cost and TCO, scalability, Web integration, legacy interface requirements, processing options, security issues, and corporate portals.

Enterprise resource planning (ERP) establishes an enterprise-wide strategy for IT resources and specific standards for data, processing, network, and user interface design. Companies can extend ERP systems to suppliers and customers in a process called supply chain management. A systems analyst must assess initial cost and TCO and ensure that the design is scalable. Scalability means that a system can be expanded, modified, or downsized easily to meet business needs. The analyst also must consider if the system will be Web-centric and follow Internet design protocols, and if it must interface with existing systems, called legacy systems. System security is an important concern throughout the design process, especially for e-commerce applications that involve credit card and personal data. Processing options affect system design and resources required. The planned architecture can include a corporate portal which is an entrance to a multifunction Web site. Corporate portals can provide access for customers, employees, suppliers, and others.

An architecture requires servers and clients. Servers are computers that supply data, processing services, or other support to one or more computers called clients. In mainframe architecture, the server performs all processing, and terminals communicate with the centralized system. Clients can be connected in distributed systems to form local area networks (LANs) or wide area networks (WANs).

Client/server architecture divides processing between one or more 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. In a typical client/server interaction, the client submits a request for information from the server, which carries out the operation and responds to the client. Compared to file server designs, client/server systems are more scalable and flexible.

A fat, or thick, client design places all or most of the application processing logic at the client. A thin client design places all or most of the processing logic at the server. Thin client 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. Compared with maintaining a central server, fat client TCO also is higher, because of initial hardware and software requirements and the ongoing expense of maintaining and updating remote client computers. The fat client design is simpler 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 (also called n-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 or on the client, or be divided between the client and the server. In a three-tier design, the user interface runs on the client and the data is stored on the server, just as with a two-tier design. A three-tier design also has a middle layer between the client and server that processes the client requests and translates them into data access commands that can be understood and carried out by the server. The middle layer is called an application server, because it provides the application logic, or business logic. Middleware is software that connects dissimilar applications and enables them to communicate and pass data. In planning the system design, a systems analyst also must consider cost-benefit and performance issues.

The Internet has had an enormous impact on system architecture. In implementing a design, an analyst should consider e-commerce architecture, the availability of packaged solutions, and service providers. The analyst also should understand the concepts of cloud computing and Web 2.0, which are shaping the future of Internet computing. Cloud computing uses a cloud symbol to represent the Internet. The cloud, which is transparent to users, provides a hardware-independent environment where remote servers handle all processing and computing functions, and the Internet itself replaces traditional networks. Web 2.0 refers to a new generation of the Web that will encourage people to collaborate, interact, and share information more dynamically. Web 2.0 is fueling the explosive growth of social networking and group-based communications.

The most prevalent processing method today is online processing. Users interact directly with online systems that continuously process their transactions when and where they occur and continuously update files and databases. In contrast, batch systems process transactions in groups and execute them on a predetermined schedule. Many online systems also use batch processing to perform routine tasks, such as handling reports and accounting entries.

Networks allow the sharing of hardware, software, and data resources in order to reduce expenses and provide more capability to users. The network is represented by a seven-layer model called the OSI (Open Systems Interconnection) model.

The way a network is configured is called the network topology. Networks typically are arranged in five patterns: hierarchical, bus, ring, star, and mesh. A single mainframe computer usually controls a hierarchical network, a bus network connects workstations in a single-line communication path, a ring network connects workstations in a circular communication path, a star network connects workstations to a central computer or networking device called a switch, and a mesh network connects every network node to every other node. Wireless networks, or WLANs, based on IEEE 802.11 standards, have seen explosive growth, especially in situations where the flexibility of wireless is important. The IEEE 802.11n standard uses MIMO, or multipath technology, which has increased wireless network speed and range. WLANs have two major topologies: BSS and, ESS. Although wireless networks are very popular, they do have some limitations and disadvantages, including interference and security concerns.

The system design specification presents the complete systems design for an information system and is the basis for the presentations that complete the systems design phase. Following the presentations, the project either progresses to the systems development phase, requires additional systems design work, or is terminated.

Key Terms

802.11 430

802.11g 430

802.11n 430

802.16 432

access point 430–431

application logic 415

application server 415

application 409

bandwidth 419

Basic Service Set (BSS) 430

batch processing 423

Bluetooth 432

bus network 426

business logic 415

client/server architecture 413

client 411

cloud computing 418

corporate portal 411

data frames 427

data processing center 411

distributed database management system (DDBMS) 417

distributed systems 412

enterprise resource planning (ERP) 406

Extended Service Set (ESS) 431

extensibility 409

fat client 414

gateway 428

Gbps (gigabits per second) 430

hierarchical network 425

hub 427

infrastructure mode 430

Institute of Electrical and Electronics Engineers (IEEE) 430

Internet operating system 419

knee of the curve 417

legacy data 413

legacy systems 410

local area network (LAN) 412

logical topology 425

mainframe architecture 411

MAN (metropolitan area network) 432

Mbps (megabits per second) 430

mesh network 427

middleware 416

multipath design 430

multiple input/multiple output (MIMO) 430

network topology 425

node 409

n-tier 415

online system 422

OSI (Open Systems Interconnection) model 425

physical topology 425

platform 406

point-of-sale (POS) 423

portal 411

proxy server 429

ring network 427

roaming 431

router 428

scalability 409

scaling on demand 418

server 411

stand-alone 412

star network 427

supply chain management (SCM) 406

switch 427

system architecture 404

system design specification 432

terminal 435

thick client 414

thin client 414

three-tier 414

transparent 412

two-tier 414

Web 2.0 419

Web-centric 410

Wi-Fi Alliance 431

Wi-Fi (wireless fidelity) 431

wide area network (WAN) 412

wild 419

wireless access point (WAP) 431

wireless local area network (WLAN) 429

WiMAX 432

Chapter Exercises

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.

2. What is enterprise resource planning (ERP)? What is supply chain management (SCM)?

3. Suppose you had a client who never used a network. Explain, in everyday terms, the role of network servers and clients.

4. Describe client/server architecture, including fat and thin clients, client/server tiers, and middleware.

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.

6. Is batch processing still relevant? Why or why not?

7. Explain the difference between a LAN and a WAN.

8. Define the term topology, and draw a sketch of each wired and wireless network topology.

9. Explain the main difference between the BSS and ESS wireless topologies. To what kind of wireless topology do the 802.16 standards apply?

10. List the sections of a system design specification, and describe the contents.

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?

2. E-commerce has seen explosive growth in recent years. What are the most important reasons for this trend? Will it continue? Why or why not?

3. This chapter describes guidelines that a systems analyst can use when considering an architecture. In your view, are all the items of equal weight and importance, or should some be ranked higher? Justify your position.

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?

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.

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.

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.

4. Perform research on the Internet to learn about trends in wireless networking, and typical costs involved in the installation of a wireless LAN.

Apply Your Knowledge

This section contains four mini-cases. Each case describes a situation, explains your role, and requires you to apply what you learned in the chapter.

1   Green Design

After several years as a successful architectural firm in Southern California, Green Design decided to expand by adding two new business ventures: a civil engineering projects group, and a group for commercial building projects. As a senior systems analyst, you have been asked to study the situation and make recommendations.

Tasks

1. Should Green Design adopt ERP? Why or why not? Provide specific reasons.

2. Is the experience of other companies relevant? Use the Internet to locate a software platform that may be useful to Green Design. Give a summary of ERP solutions you find for architectural and engineering firms.

3. Should Green Design use separate portals for employees, customers, and suppliers?

4. Before selecting software and hardware for the new system, how should Green Design evaluate initial cost and total cost of ownership? What would be the main components?

2   Passing Lane

Passing Lane is a small trucking company headquartered in Portland, Oregon. Passing Lane’s information system consists of a file server and three workstations where freight clerks enter data, track shipments, and prepare freight bills. To perform their work, the clerks obtain data from the server and use database and spreadsheet programs stored on stand-alone PCs to process the data. At your meeting yesterday, Passing lane’s president approved your recommendation to create a relational database to handle operations and provide links for the company’s shippers and customers.

Tasks

1. Review the concept of supply chain management. Although Passing Lane offers services rather than products, could the SCM concept apply to the design of the new system? Why or why not?

2. What would be the advantages of selecting an Web-based architecture for Passing Lane’s system?

3. Since the firm is growing rapidly, what design features should be included in the new system to ensure it can grow with the company.

4. Given that Passing Lane currently uses computers for managing their operations, what design considerations should be given to legacy systems? Explain your answer.

3   Nothing But Net

Nothing But Net is an IT consulting firm that specializes in network architectural design. As a newly hired systems analyst, you have been asked to explain the advantages and disadvantages of a variety of networking concepts. Your answers will be incorporated into a FAQ section of the new marketing brochure.

Tasks

1. Should an organization choose a new system based on client/server architecture? Why or why not?

2. Explain the pros and cons of thick or thin client characteristics.

3. What is the difference between physical and logical topology? Provide examples.

4. Will mobile devices replace desktop system units and traditional laptop computers? How would networks have to change if that were to happen?

4   Alice’s Restaurant Supply

Alice’s Restaurant Supply offers a line of specialty food products to institutional customers and restaurant chains. The firm prides itself on using only the finest ingredients and preparation methods. The owner, Alice Burns, hired you as an IT consultant to help her plan the system architecture for a new WLAN that will connect employee computers to the wired network. She asked you to start with the following questions:

Tasks

1. What wireless standards could be implemented in the new system? What are the pros and cons of each standard?

2. Choose a wireless standard to implement in Alice’s Restaurant Supply, and explain your choice.

3. Suppose that microwave ovens and cordless telephones are used extensively in some parts of the facility. Would that affect your IEEE 802.11 amendment choice? What standards would not be a good choice in this type of environment?

4. Suppose that the new WLAN will also provide roaming services for employees who must use portable computers and tablets in many warehouse locations. Which wireless topology would be the best choice? Explain your answer.

Case Studies

Each chapter includes a Chapter Case, a Continuing Case, a Capstone Case, and an Online Case Simulation. You can learn more about the Online Case Simulation in the MIS CourseMate Features section.

Chapter Case: Precision Consulting

Background

Precision Consulting has helped many clients plan, design, and implement e-commerce solutions. As a newly hired systems analyst, you will be expected to work with other team members on e-commerce projects. You realize that have a lot to learn, and you decide to learn as much as you can about the e-commerce issues and solutions.

Tasks

1. Perform research to learn how much consumers are projected to spend on Internet purchases during the next three years, and describe the results. Does the estimate seem reasonable? Why or why not?

2. Many of Precision’s clients are start-up firms that must fight hard to attract investment capital, and some traditional lenders are skeptical of new Web-based firms. Perform research to determine the mortality rate of new retail firms that use the Web as their primary marketing channel, and describe the results of your research.

3. Some IT professionals predict that traditional brick and mortar companies will greatly expand their Internet marketing efforts, making it even harder for new online firms to compete. Perform research to find out more about the topic and describe the results.

4. Suppose you were asked to draft an e-commerce sales brochure for Precision Consulting. List all the services in which potential customers might be interested.

Continuing Case: Personal Trainer, Inc.

Personal Trainer, Inc. owns and operates fitness centers in a dozen Midwestern cities. The centers have done well, and the company is planning an international expansion by opening a new “supercenter” in the Toronto area. Personal Trainer’s president, Cassia Umi, hired an IT consultant, Susan Park, to help develop an information system for the new facility. During the project, Susan will work closely with Gray Lewis, who will manage the new operation.

Background

Susan and Gray finished their work on user interface, input, and output design. They developed a user-centered design that would be flexible and easy to learn. Now Susan turned her attention to the architecture for the new system.

Susan wanted to consider their own organization and culture, enterprise resource planning, total cost of ownership, scalability, Web integration, legacy systems, processing methods, security issues, and corporate portal. She also needed to select a network plan, or topology, that would dictate the physical cabling and network connections, or consider a wireless network. When all these tasks were completed, she would submit a system design specification for approval.

Tasks

1. What would be the advantages of selecting an Internet-based architecture for the Personal Trainer’s system?

2. If Personal Trainer wants to increase its Internet marketing efforts, what advice could you offer? Perform research to find out more about the topic of Web-based marketing before you answer Gray.

3. What software and hardware infrastructure will be necessary to ensure Personal Trainer can process point of sale transactions?

4. Prepare an outline for a system design specification and describe the contents of each section.

Capstone Case: New Century Wellness Group

New Century Wellness Group offers a holistic approach to healthcare with an emphasis on preventive medicine as well as traditional medical care. In your role as an IT consultant, you will help New Century develop a new information system.

Background

The New Century partners accepted your interface, output, input, and data designs and your recommendation to install a server and desktop computer clients on a local area network. At this point, you review your notes and plan the architecture for the New Century system.

New Century Wellness Group has four primary care physicians, one nurse practitioner (NP), four physical therapists, one registered nutritionist, eight nurses, and eight support staff. Each of the physicians, NP, therapists, nutritionist and support staff has their own workstations. The nurses work from one of three nurse stations that should have at least three computers at each station. Each nurse station will have a high-volume network laser printer and a scanner attached to one workstation. The checkin/checkout area will have an impact printer for multipart forms and a network laser printer. The network will include an online backup service, Internet access via a cable connection with a local cable company.

The partners want you to ensure the physical network is scalable, and able to handle the electronic medical record phase after the business support system is implemented. The electronic medical record phase will require a computer or thin client to be installed in each exam room and procedure room. They will also use portable computers and tablets to access patient information as the providers move from room to room around the clinic.

The hardware requirements are only part of the final installation plan which you must develop. You should start by reviewing the DFDs and object-oriented diagrams that you prepared in the systems analysis phase, and the ERDs and table designs that you created in the systems design phase. Then, review the system architecture checklist at the beginning of this chapter. With this information, you should be able to prepare a system design specification.

Tasks

1. Draw a simple floor plan for New Century Wellness group and include the placement of all network nodes including the placement of a server, and network equipment. How many ports will your switch need to accommodate?

2. Given this information, what physical and logical topologies would you recommend for New Century? Explain your answer.

3. What would be the benefits of using a wireless network? Are there any drawbacks?

4. Using the information you just prepared, as well as other information you developed for in previous chapters, prepare a system design specification that includes sections on the management summary, system components, system environment, implementation requirements, and time and cost estimates.

CASE Tool Workshop

Systems analysts use CASE tools to help them plan, build, and maintain information systems. To learn more about CASE tools, turn to Part B of the Toolkit that follows Chapter 12. You can complete these tasks with theVisible Analyst® CASE tool, which is available with this textbook, or a similar tool.

Background

Suppose you work as a computer lab assistant at your school. The lab supervisor wants to install a CASE tool on the network, but realizes there might be licensing issues.

Tasks

1. Visit the Web site for Visible Analyst® or another CASE tool, and investigate licensing options. Are network installations limited by the number of workstations, the number of users at any one time, or other constraints? Write a brief report with your findings.

2. The lab supervisor also told you that several computer science instructors want to assign team projects, where students would collaborate using a Web-based CASE tools that can run on mobile devices as well as lab workstations. She wants you to do research and determine whether such tools exist. Go online, see what you can find, and report back to her.

MIS CourseMate Features

If you have an MIS CourseMate access code, you can reinforce and extend your learning with premium content created for this textbook. For example, you can launch interactive Video Learning Sessions to help you understand systems development concepts and practice your skills. In addition, you can use MindTap Reader, which is a full, interactive, digital e-book.

MIS CourseMate also offers many learning features within each chapter, including an Online Case Simulation, a Critical Thinking Challenge, Video Learning Session Tasks, and a set of Learn It Online activities. To log on to the MIS CourseMate site at www.cengagebrain.com, you must create a student account and register this book.

Online Case Simulation: SCR Associates

Session 10: System Architecture

Overview

The SCR Associates case study is a Web-based simulation that allows you to practice your skills in a real-world environment. The firm offers IT consulting, solutions and training. SCR plans to open a new high-tech training center, and needs to develop a Training Information Management System (TIMS) to support the center. You are a newly hired systems analyst reporting to Jesse Baker, systems group manager, and will help her develop the system.

The case study takes you to the SCR Web site, where you receive e-mail and voice mail messages from Jesse, obtain information from SCR’s resource libraries, and perform various tasks. Jesse has high standards, but seems very fair. She made it clear that she expects your work to be accurate, thorough, and professional.

Before You Begin

To prepare for this work session, you should review the following topics:

• ERP, TCO, and network topology

• The sections of a system design specification

How Do I Use the Online Case Simulation?

• Read the preview, and review the Chapter 1 background material if necessary.

• Visit the MIS CourseMate Web site at www.cengagebrain.com, locate the SCR Case Simulation, and click the intranet link. Enter your name and the password sad 10e.

• When the opening screen displays, select this session. Then check your e-mail and voice mail, and start to work on your task list.

Preview: Session 10

Your supervisor, Jesse Baker, wants you to be familiar with the main issues that a systems analyst should consider when planning an architecture, including corporate organization and culture, enterprise resource planning, initial costs and TCO, scalability, Web integration, legacy interface requirements, processing options, security, and corporate portal issues.

Critical Thinking Challenge

In addition to technical ability IT professionals need critical thinking skills. This feature can help you practice perception, organization, analysis, problem-solving, and decision-making skills that will be valuable in the workplace. You can visit www.criticalthinking.org to learn more about critical thinking and why it is so important.

Background

The IT team at Game Technology is working on an overall architecture for the new C3 system. They solicited RFPs from several hardware vendors, and decided to work with Network Illusions, a well-known local firm. Your job is to help analyze the server test results, and to draw network diagrams when requested.

The Network Illusions sales rep recommended a Model DX server for the C3 network, and submitted the following data, which shows projected network response times for various numbers of Game Technology users:

Practice Tasks

Visit the MIS CourseMate Web site at www.cengagebrain.com. Then navigate to the resources for this chapter and locate the Critical Thinking Challenge feature. You will complete two Practice Tasks, using what you learned in the chapter. Then you can check your answers to be sure you’re ready for the Challenge Tasks.

Challenge Tasks

After you complete the Practice Tasks, you learn about new developments at Game Technology.

Although the spec was for a Model DX server, Network Illusions delivered a newer model, called the DX+. The vendor sales rep said that performance would be the same or better, but the IT team decided to run a series of response time tests. To continue, navigate to the Critical Thinking Challenge feature for this chapter, select the Challenge Tasks, and follow the instructions.

Video Learning Sessions

© craftvision/iStockphoto

Video Learning Sessions can help you understand systems development concepts and practice your skills. In this scenario, you will help design a Video Learning Session for this chapter.

Before You Begin

Review the chapter and list the main topics. Which ones did you find difficult to understand, and why? Can you think of other ways to explain the topics?

Training Tasks

Suppose the IT training manager wants to encourage team members to watch the Video Learning Sessions. She wants you to submit a proposal for a new session that would explain the key topics in this chapter.

1. Which topics would you choose?

2. What specific skills or concepts would you include in the session?

3. How would you present the material?

4. Describe at least three graphic images that you would include in the video session.

Learn It Online

In each chapter, you can use this feature to apply your knowledge and practice your skills. The exercises include Chapter Reinforcement Questions, Flash Cards, Practice Tests, and various games, such as Who Wants To Be a Computer Genius?, Wheel of Terms, and the Crossword Puzzle Challenge.