Systems Development

Systems Development

which a subsystem performs a single function. In the MP3 player example, supplying power is a single function.

This brief discussion of systems should better prepare you to think about computer-based information systems and how they are built. Many of the same principles that apply to systems in general apply to information systems as well. In the next section, we review how the information systems development process and the tools that have supported it have changed over the decades.

A Modern Approach to Systems Analysis and Design Today, systems development focuses on systems integration. Systems integra- tion allows hardware and software from different vendors to work together in an application. It also enables existing systems developed in procedural lan- guages to work with new systems built with visual programming environments. Developers use visual programming environments, such as Visual Basic, to de- sign the user interfaces for systems that run on client/server platforms. In a client/server environment, some of the software runs on the server, a powerful computer designed to allow many people access to software and data stored on it, and some of the software runs on client machines. Client machines are the PCs you use at your desk at work. The database usually resides on the server. These relationships are shown in Figure 1-7. The Internet is also organized in a client/server format. With the browser software on your home PC, you can get files and applications from many different computers throughout the world. Your home PC is the client, and all of the Internet computers are servers.

Alternatively, organizations may purchase an enterprise-wide system from companies such as SAP (Systems, Applications, and Products in Data Processing) or Oracle. Enterprise-wide systems are large, complex systems that consist of a series of independent system modules. Developers assemble systems by choosing and implementing specific modules. Enterprise-wide systems usually contain software to support many different tasks in an organization rather than only one or two functions. For example, an enterprise-wide system may handle all human resources management, payroll, benefits, and retirement functions within a single, integrated system. It is, in fact, increasingly rare for organiza- tions to develop systems in-house anymore. Chapter 2 will introduce you to the

Server

Clients

Database

FIGURE 1-7 The client/server model.

Cohesion The extent to which a system or subsystem performs a single function.

Systems analyst The organizational role most responsible for the analysis and design of information systems.

Chapter 1 The Systems Development Environment 11

various sources of information systems technology. First, however, you must gain some insight into what your role will be in the systems development process.

Your Role in Systems Development Although many people in organizations are involved in systems analysis and design, the systems analyst has the primary responsibility. A career as a systems analyst will allow you to have a significant impact on how your organization operates. This fast-growing and rewarding position is found in both large and small companies. IDC, a leading consulting group, predicts that growth in information technology (IT) employment will exceed 3 percent per year through at least 2013. The Bureau of Labor Statistics predicts additional increases in the numbers of IT jobs from 2004 to 2014. During this period, the professional IT workforce is projected to add more than 1 million new jobs in the United States. Information technology workers remain in demand.

The primary role of a systems analyst is to study the problems and needs of an organization in order to determine how people, methods, and information technology can best be combined to bring about improvements in the organiza- tion. A systems analyst helps system users and other business managers define their requirements for new or enhanced information services.

Systems analysts are key to the systems development process. To succeed as a systems analyst, you will need to develop four types of skills: analytical, technical, managerial, and interpersonal. Analytical skills enable you to un- derstand the organization and its functions, to identify opportunities and problems, and to analyze and solve problems. One of the most important an- alytical skills you can develop is systems thinking, or the ability to see or- ganizations and information systems as systems. Systems thinking provides a framework from which to see the important relationships among informa- tion systems, the organizations they exist in, and the environment in which the organizations themselves exist. Technical skills help you understand the potential and the limitations of information technology. As an analyst, you must be able to envision an information system that will help users solve problems and that will guide the system’s design and development. You must also be able to work with programming languages such as C�� and Java, var- ious operating systems such as Windows and Linux, and computer hardware platforms such as IBM and Mac. Management skills help you manage proj- ects, resources, risk, and change. Interpersonal skills help you work with end users as well as with other analysts and programmers. As a systems analyst, you will play a major role as a liaison among users, programmers, and other systems professionals. Effective written and oral communication, including competence in leading meetings, interviewing end users, and listening, are key skills that analysts must master. Effective analysts successfully combine these four types of skills, as Figure 1-8 (a typical advertisement for a systems analyst position) illustrates.

Let’s consider two examples of the types of organizational problems you could face as a systems analyst. First, you work in the information systems de- partment of a major magazine company. The company is having problems keep- ing an updated and accurate list of subscribers, and some customers are getting two magazines instead of one. The company will lose money and subscribers if these problems continue. To create a more efficient tracking system, the users of the current computer system as well as financial managers submit their prob- lem to you and your colleagues in the information systems department. Second, you work in the information systems department at a university, where you are called upon to address an organizational problem such as the mailing of student grades to the wrong addresses.

Systems development life cycle (SDLC) The series of steps used to mark the phases of development for an information system.

Systems development methodology A standard process followed in an organization to conduct all the steps necessary to analyze, design, implement, and maintain information systems.

12 Part I Foundations for Systems Development

1.

2.

3.

A bachelor’s degree in management information systems or computer science.

Simon & Taylor, Inc., a candle manufacturer, has an immediate opening for a systems analyst in its Vermont-based office.

The ideal candidate will have:

We offer a competitive salary, relocation assistance, and the challenges of working in a state-of-the-art IT environment.

Two years’ experience with UNIX/LINUX.

Experience with C, Java, and/or other object-oriented programming languages, and with application development environments such as Visual Studio or IBM’s Rational Unified Process.

  1. LAN-related skills and experience.
  2. Familiarity with distribution and manufacturing concepts (allocation, replenishment, shop floor control, and production scheduling).
  3. Working knowledge of project management and all phases of the systems development life cycle.
  4. Strong communication skills.

Simon & Taylor, Inc., is an equal opportunity employer.

E-mail your resume to HR@simontaylor.com.

FIGURE 1-8 A job advertisement for a systems analyst.

When developing information systems to deal with problems such as these, an organization and its systems analysts have several options: They can go to an in- formation technology services firm, such as Accenture or EDS, an HP Company, to have the system developed for them; they can buy the system off the shelf; they can implement an enterprise-wide system from a company such as SAP; they can obtain open-source software; or they can use in-house staff to develop the sys- tem. Alternatively, the organization can decide to outsource system development and operation. All of these options are discussed in detail in Chapter 2.

Developing Information Systems and the Systems Development Life Cycle Organizations use a standard set of steps, called a systems development methodology, to develop and support their information systems. Like many processes, the development of information systems often follows a life cycle. For example, a commercial product, such as a Nike sneaker or a Honda car, follows a life cycle: It is created, tested, and introduced to the market. Its sales increase, peak, and decline. Finally, the product is removed from the market and is replaced by something else. The systems development life cycle (SDLC) is a common methodology for systems development in many organizations. It marks the phases or steps of information systems development: Someone has an idea for an information system and what it should do. The organization that will use the system decides to devote the necessary resources to acquiring it. A careful study is done of how the organization currently handles the work the system will support. Professionals develop a strategy for designing the new sys- tem, which is then either built or purchased. Once complete, the system is in- stalled in the organization, and after proper training, the users begin to incorporate the new system into their daily work. Every organization uses a slightly different life-cycle model to model these steps, with anywhere from three to almost twenty identifiable phases. In this book, we highlight four SDLC

Chapter 1 The Systems Development Environment 13

steps: (1) planning and selection, (2) analysis, (3) design, and (4) implementa- tion and operation (see Figure 1-9).

Although any life cycle appears at first glance to be a sequentially ordered set of phases, it actually is not. The specific steps and their sequence are meant to be adapted as required for a project. For example, in any given SDLC phase, the project can return to an earlier phase, if necessary. Similarly, if a commercial product does not perform well just after its introduction, it may be temporar- ily removed from the market and improved before being reintroduced. In the systems development life cycle, it is also possible to complete some activities in one phase in parallel with some activities of another phase. Sometimes the life cycle is iterative; that is, phases are repeated as required until an accept- able system is found. Some systems analysts consider the life cycle to be a spiral, in which we constantly cycle through the phases at different levels of detail, as illustrated in Figure 1-10. The circular nature of the life-cycle dia- gram in Figure 1-10 illustrates how the end of the useful life of one system

Systems Planning and

Selection

Systems Analysis

Systems Design

Systems Implementation and Operation SDLC

FIGURE 1-9 The systems development life cycle (SDLC).

Planning Risk

Assessment

Engineering

Construction and Release

Customer Evaluation

Customer Communication

Go/No-Go Axis

FIGURE 1-10 Evolutionary model SDLC.

Systems analysis Phase of the SDLC in which the current system is studied and alternative replacement systems are proposed.

Systems planning and selection The first phase of the SDLC, in which an organization’s total information system needs are analyzed and arranged, and in which a potential information systems project is identified and an argument for continuing or not continuing with the project is presented.

14 Part I Foundations for Systems Development

leads to the beginning of another project that will replace the existing system altogether. However conceived, the systems development life cycle used in an organization is an orderly set of activities conducted and planned for each development project. The skills required of a systems analyst apply to all life- cycle models.

Every medium-to-large corporation, such as Wal-Mart, and every custom soft- ware producer, such as SAP, will have its own specific, detailed life cycle or sys- tems development methodology in place. Even if a particular methodology does not look like a cycle, many of the SDLC steps are performed, and SDLC tech- niques and tools are used. This book follows a generic SDLC model, as illus- trated in Figure 1-9. We use this SDLC as an example of methodology and a way to think about systems analysis and design. You can apply this methodology to almost any life cycle. As we describe this SDLC throughout the book, it becomes clear that each phase has specific outcomes and deliverables that feed impor- tant information to other phases. At the end of each phase (and sometimes within phases for intermediate steps), a systems development project reaches a milestone. Then, as deliverables are produced, they are often reviewed by parties outside the project team, including managers and executives.

Phase 1: Systems Planning and Selection The first phase in the SDLC, systems planning and selection, has two pri- mary activities. First, someone identifies the need for a new or enhanced sys- tem. Information needs of the organization are examined, and projects to meet these needs are identified. The organization’s information system needs may re- sult from:

� Requests to deal with problems in current procedures

� The desire to perform additional tasks

� The realization that information technology could be used to capitalize on an existing opportunity

The systems analyst prioritizes and translates the needs into a written plan for the information systems (IS) department, including a schedule for developing new major systems. Requests for new systems spring from users who need new or enhanced systems. During the systems planning and selection phase, an organization determines whether resources should be devoted to the develop- ment or enhancement of each information system under consideration. A feasibility study is conducted before the second phase of the SDLC to deter- mine the economic and organizational impact of the system.

Phase 2: Systems Analysis The second phase of the systems development life cycle is systems analysis. During this phase, the analyst thoroughly studies the organization’s current

The second task in the systems planning and selection phase is to investigate the system and determine the proposed system’s scope. The team of systems analysts then produces a specific plan for the proposed project for the team to follow. This baseline project plan customizes the standardized SDLC and speci- fies the time and resources needed for its execution. The formal definition of a project is based on the likelihood that the organization’s IS department is able to develop a system that will solve the problem or exploit the opportunity and determine whether the costs of developing the system outweigh the possible benefits. The final presentation to the organization’s management of the plan for proceeding with the subsequent project phases is usually made by the project leader and other team members.

Systems design Phase of the SDLC in which the system chosen for development in systems analysis is first described independently of any computer platform, (logical design) and is then transformed into technology-specific details (physical design) from which all programming and system construction can be accomplished.

Chapter 1 The Systems Development Environment 15

procedures and the information systems used to perform tasks such as general ledger, shipping, order entry, machine scheduling, and payroll. Analysis has several subphases. The first subphase involves determining the requirements of the system. In this subphase, you and other analysts work with users to determine what the users want from a proposed system. This subphase involves a careful study of any current systems, manual and computerized, that might be replaced or enhanced as part of this project. Next, you study the requirements and structure them according to their interrelationships, eliminating any redundancies. As part of structuring, you generate alternative initial designs to match the requirements. Then you compare these alternatives to determine which best meets the requirements within the cost, labor, and technical levels the organization is willing to commit to the development process. The output of the analysis phase is a description of the alternative solution recommended by the analysis team. Once the recommendation is accepted by the organization, you can make plans to acquire any hardware and system software necessary to build or operate the system as proposed.

Phase 3: Systems Design The third phase of the SDLC is called systems design. During systems design, analysts convert the description of the recommended alternative solution into logical and then physical system specifications. You must design all aspects of the system from input and output screens to reports, databases, and computer processes.

Logical design is not tied to any specific hardware and systems software plat- form. Theoretically, the system you design could be implemented on any hardware and systems software. Logical design concentrates on the business aspects of the system; that is, how the system will impact the functional units within the organization. Figure 1-11 shows both the logical design for a product and its physical design, side by side, for comparison. You can see from the comparison that many specific decisions had to be made to move from the logical model to the physical product. The situation is similar in information systems design.

In physical design, you turn the logical design into physical, or technical, spec- ifications. For example, you must convert diagrams that map the origin, flow, and processing of data in a system into a structured systems design that can then be broken down into smaller and smaller units for conversion to instruc- tions written in a programming language. You design the various parts of the system to perform the physical operations necessary to facilitate data capture, processing, and information output. During physical design, the analyst team decides which programming languages the computer instructions will be writ- ten in, which database systems and file structures will be used for the data, and which hardware platform, operating system, and network environment the sys- tem will run under. These decisions finalize the hardware and software plans initiated at the end of the analysis phase. Now you can acquire any new tech- nology not already present in the organization. The final product of the design phase is the physical system specifications, presented in a form, such as a dia- gram or written report, ready to be turned over to programmers and other sys- tem builders for construction.

Phase 4: Systems Implementation and Operation The final phase of the SDLC is a two-step process: systems implementation and operation. During systems implementation and operation, you turn sys- tem specifications into a working system that is tested and then put into use. Implementation includes coding, testing, and installation. During coding, programmers write the programs that make up the system. During testing, programmers and analysts test individual programs and the entire system in

Systems implementation and operation Final phase of the SDLC, in which the information system is coded, tested, and installed in the organization, and in which the information system is systematically repaired and improved.

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