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Systems Analysis and Design - Complete Introductory Tutorial for Software Engineering

Computers are fast becoming our way of life and one cannot imagine life without computers in today’s world. You go to a railway station for reservation, you want to web site a ticket for a cinema, you go to a library, or you go to a bank, you will find computers at all places. Since computers are used in every possible field today, it becomes an important issue to understand and build these computerized systems in an effective way.  

Building such systems is not an easy process but requires certain skills and capabilities to understand and follow a systematic procedure towards making of any information system. For this, experts in the field have devised various methodologies. Waterfall model is one of the oldest methodologies. Later Prototype Model, Object Oriented Model, Dynamic Systems Development Model, and many other models became very popular for system development. For anyone who is a part of this vast and growing Information Technology industry, having basic understanding of the development process is essential. For the students aspiring to become professionals in the field a thorough knowledge of these basic system development methodologies is very important.

In this web site we have explored the concepts of system development. The web site starts with the system concepts, making the reader understand what does system mean in general and what are information systems in specific. The web site then talks about the complete development process discussing the various stages in the system development process. The different types of system development methodologies, mentioned above, are also explained.

This tutorial is for beginners to System Analysis and Design (SAD) Process. If you are new to computers and want to acquire knowledge about the process of system development, then you will find useful information in this tutorial. This tutorial is designed to explain various aspects of software development and different techniques used for building the system. This tutorial is a good introductory guide to the need and overall features of software engineering.

This tutorial is designed to introduce Software Engineering concepts to the upcoming software professionals. It assumes that its reader does not know anything about the system development process. However it is assumed that the reader knows the basics of computers.

What is Software Engineering? 

Software Engineering is the systematic approach to the development, operation and maintenance of software. Software Engineering is concerned with development and maintenance of software products.

The primary goal of software engineering is to provide the quality of software with low cost. Software Engineering involves project planning, project management, systematic analysis, design, validations and maintenance activities

System Analysis and Design Contents 

1. Introduction to Systems

2. Software (System) Development Life Cycle Models

3. Preliminary Analysis

4. Fact Finding and Decision Making Techniques

5. Functional Modeling I

6. Functional Modeling II

7. Data Modeling Techniques

8. Relational Data Modeling and Object Oriented Data Modeling Techniques

9. Testing and Quality Assurance

Brief Explanation of the chapters in this tutorial

1. Introduction to Systems  - Introduces the concept of systems to the reader and explains what an information system is. It talks about various types of information systems and their relevance to the functioning of any organization. This chapter also gives a brief introduction to system analysis and design.

2. Software (System) Development Life Cycle Models - Explains various activities involved in the development of software systems. It presents the different approaches towards software development. In this chapter, Waterfall Model, Prototype Model, Dynamic System Development Model, and Object Oriented models are discussed.

3. Preliminary Analysis - covers various activities that are performed during the preliminary analysis of the system development. It shows how the feasibility study for the system to be developed is done. Also in the later part of the chapter various software estimation techniques are discussed.

4. Fact Finding and Decision Making Techniques - shows the various techniques used for fact finding during the analysis of the system. In this, interviews, questionnaires, on site observation, and record reviews are presented. This chapter also discusses the decision-making and documentation techniques. For this Decision Tables, Decision Tress, Structured English and Data Dictionary is presented.

5. Functional Modeling I - presents the various concepts of system design. Design elements like input-output to the system, processes involved in the system and the database elements of the system are discussed. It also discusses Data Flow Diagrams that are used to represent the functionality of the system.

6. Functional Modeling II - introduces the modular programming concept to the software development. It explains the structure charts that represent the modular structure of various modules of the software being developed. Concepts like Cohesion and Coupling that further enhance the users understanding of modular designing are also presented.

7. Data Modeling Techniques  - presents the concepts involve in the data modeling phase of system development where the storage of data and the storage form is discussed. Here Entity Relationship model along with Entity Relationship Diagrams is used to illustrate the data modeling concepts. are discussed.

8. Relational Data Modeling and Object Oriented Data Modeling Techniques - is an extension to the chapter 7 (Data Modeling Techniques). Here two other data models, Relational and Object Oriented Models are discussed. Comparison of the two models is also presented.

9. Testing and Quality Assurance  - covers the various testing techniques and strategies employed during the development of the system. Also various quality assurance activities for software development are presented

What is a System? 

The term “system” originates from the Greek term syst¯ema, which means to “place together.” Multiple business and engineering domains have definitions of a system. This text defines a system as:  

·         System An integrated set of interoperable elements, each with explicitly specified and bounded capabilities, working synergistically to perform value-added processing to enable a User to satisfy mission-oriented operational needs in a prescribed operating environment with a specified outcome and probability of success. 

To help you understand the rationale for this definition, let’s examine each part in detail.

System Definition Rationale

The definition above captures a number of key discussion points about systems. Let’s examine the basis for each phrase in the definition.

·                  By “an integrated set,” we mean that a system, by definition, is composed of hierarchical levels of physical elements, entities, or components.

·                  By “interoperable elements,” we mean that elements within the system’s structure must be compatible with each other in form, fit, and function, for example. System elements include equipment (e.g., hardware and system, system, facilities, operating constraints, support), maintenance, supplies, spares, training, resources, procedural data, external systems, and anything else that supports mission accomplishment.

One is tempted to expand this phrase to state “interoperable and complementary.” In general, system elements should have complementary missions and objectives with non-overlapping capabilities. However, redundant systems may require duplication of capabilities across several system elements. Additionally, some systems, such as networks, have multiple instances of the same components.

·                  By each element having “explicitly specified and bounded capabilities,” we mean that every element should work to accomplish some higher level goal or purposeful mission. System element contributions to the overall system performance must be explicitly specified. This requires that operational and functional performance capabilities for each system element be identified and explicitly bounded to a level of specificity that allows the element to be analyzed, designed, developed, tested, verified, and validated—either on a stand-alone basis or as part of the integrated system.

·                  By “working in synergistically,” we mean that the purpose of integrating the set of elements is to leverage the capabilities of individual element capabilities to accomplish a higher level capability that cannot be achieved as stand-alone elements.

·                  By “value-added processing,” we mean that factors such operational cost, utility, suitability, availability, and efficiency demand that each system operation and task add value to its inputs availability, and produce outputs that contribute to achievement of the overall system mission outcome and performance objectives.

·                  By “enable a user to predictably satisfy mission-oriented operational needs,” we mean that every system has a purpose (i.e., a reason for existence) and a value to the user(s). Its value may be a return on investment (ROI) relative to satisfying operational needs or to satisfy system missions and objectives.

·                  By “in a prescribed operating environment,” we mean that for economic, outcome, and survival reasons, every system must have a prescribed—that is, bounded—operating environment.

·                  By “with a specified outcome,” we mean that system stakeholders (Users, shareholders, owners, etc.) expect systems to produce results. The observed behavior, products, byproducts, or services, for example, must be outcome-oriented, quantifiable, measurable, and verifiable.

·                  By “and probability of success,” we mean that accomplishment of a specific outcome involves a degree of uncertainty or risk. Thus, the degree of success is determined by various performance factors such as reliability, dependability, availability, maintainability, sustainability, lethality, and survivability.

You need at least four types of agreement on working level definitions of a system:

1. A personal understanding 
2. A program team consensus 
3. An organizational (e.g., System Developer) consensus, and 
4. Most important, a contractual consensus with your customer. 

Why? Of particular importance is that you, your program team, and your customer (i.e., a User or an Acquirer as the User’s technical representative) have a mutually clear and concise understanding of the term. Organizationally you need a consensus of agreement among the System Developer team members. The intent is to establish continuity across contract and organizations as personnel transition between programs.

Other Definitions of a System

National and international standards organizations as well as different authors have their own definitions of a system. If you analyze these, you will find a diversity of viewpoints, all tempered by their personal knowledge and experiences. Moreover, achievement of a “one size fits all” convergence and consensus by standards organizations often results in wording that is so diluted that many believe it to be insufficient and inadequate. Examples of organizations having standard definitions include:

·         International Council on Systems Engineering (INCOSE) 

·         Institute of Electrical and Electronic Engineers (IEEE) 

·         American National Standards Institute (ANSI)/Electronic Industries Alliance (EIA) 

·         International Standards Organization (ISO) 

·         US Department of Defense (DoD) 

·         US National Aeronautics and Space Administration (NASA) 

·         US Federal Aviation Administration (FAA) 

You are encouraged to broaden your knowledge and explore definitions by these organizations. You should then select one that best fits your business application. Depending on your personal viewpoints and needs, the definition stated in this text should prove to be the most descriptive characterization.

Closing Point

When people develop definitions, they attempt to create content and grammar simultaneously. People typically spend a disproportionate amount of time on grammar and spend very little time on substantive content. We see this in specifications and plans, for example. Grammar is important, since it is the root of our language and communications. However, wordsmith grammar has no value if it lacks substantive content.

You will be surprised how animated and energized people become over wording exercises. Subsequently, they throw up their hands and walk away. For highly diverse terms such as a system, a good definition may sometimes be simply a bulleted list of descriptors concerning what a term is or, perhaps, is not. So, if you or your team attempts to create your own definition, perform one step at a time. Obtain consensus on the key elements of substantive content. Then, structure the statement in a logical sequence and translate the structure into grammar.

Learning to Recognize Types of Systems 

Systems occur in a number of forms and vary in composition, hierarchical structure, and behavior. Consider the next high-level examples.  

·                  Economic systems

·                  Educational systems

·                  Financial systems

·                  Environmental systems

·                  Medical systems

·                  Corporate systems

·                  Insurance systems

·                  Religious systems

·                  Social systems

·                  Psychological systems

·                  Cultural systems

·                  Food distribution systems

·                  Transportation systems

·                  Communications systems

·                  Entertainment systems

·                  Government systems
Legislative systems, Judicial systems, Revenue systems, Taxation systems, Licensing systems, Military systems, Welfare systems, Public safety systems, Parks and recreation systems, Environmental systems

If we analyze these systems, we find that they produce combinations of products, by-products, or services. Further analysis reveals most of these fall into one or more classes such as individual versus organizational; formal versus informal; ground-based, sea-based, air-based, space-based, or hybrid; human-in-the-loop (HITL) systems, open loop versus closed loop; and fixed, mobile, and transportable systems

Delineating Systems, Products and Tools 

People often confuse the concepts of systems, products, and tools. To facilitate our discussion, let’s examine each of these terms in detail.  

System Context 

We defined the term system earlier in this section. A system may consist of two or more integrated elements whose combined—synergistic—purpose is to achieve mission objectives that may not be effectively or efficiently accomplished by each element on an individual basis. These systems typically include humans, products, and tools to varying degrees. In general, human-made systems require some level of human resources for planning, operation, intervention, or support.

Product Context

Some systems are created as a work product by other systems. Let’s define the context of product: a product, as an ENABLING element of a larger system, is typically a physical device or entity that has a specific capability—form, fit, and function—with a specified level of performance.

Products generally lack the ability—meaning intelligence—to self-apply themselves without human assistance. Nor can products achieve the higher level system mission objectives without human intervention in some form. In simple terms, we often relate to equipment-based products as items you can procure from a vendor via a catalog order number. Contextually, however, a product may actually be a vendor’s “system” that is integrated into a User’s higher-level system. Effectively, you create a system of systems (SoS).

Example 

1. A hammer, as a procurable product has form, fit, and function but lacks the ability to apply its self to hammering or removing nails.

2. Ajet aircraft, as a system and procurable vendor product, is integrated into an airline’s system and may possess the capability, when programmed and activated by the pilot under certain conditions, to fly.

Tool Context

Some systems or products are employed as tools by higher level systems. Let’s define what we mean by a tool. A tool is a supporting product that enables a user or system to leverage its own capabilities and performance to more effectively or efficiently achieve mission objectives that exceed the individual capabilities of the User or system.

Example 

1. A simple fulcrum and pivot, as tools, enable a human to leverage their own physical strength to displace a rock that otherwise could not be moved easily by one human.

2. A statistical software application, as a support tool, enables a statistician to efficiently analyze large amounts of data and variances in a short period of time.

Analytical Representation of a System 

As an abstraction we symbolically represent a system as a simple entity by using a rectangular box as shown in Figure 1. In general, inputs such as stimuli and cues are fed into a system that processes the inputs and produces an output. As a construct, this symbolism is acceptable; however, the words need to more explicitly identify WHAT the system performs. That is, the system must add value to the input in producing an output.  

We refer to the transformational processing that adds value to inputs and produces an output as a capability. You will often hear people refer to this as the system’s functionality; this is partially correct. Functionality only represents the ACTION to be accomplished; not HOW WELL as characterized by performance. This text employs capability as the operative term that encompasses both the functionality and performance attributes of a system.

The simple diagram presented in Figure 1 represents a system. However, from an analytical perspective, the diagram is missing critical information that relates to how the system operates and performs within its operating environment. Therefore, we expand the diagram to identify these missing elements. The result is shown in Figure 2. The attributes of the construct—which include desirable/undesirable inputs, stakeholders, and desirable/undesirable outputs—serve as a key checklist to ensure that all contributory factors are duly considered when specifying, designing, and developing a system.

Figure 1 - Basic System Entity Construct

Figure 2 - Analytical System Entity Construct 

Systems that Require Engineering 

Earlier we listed examples of various types of systems. Some of these systems are workflow-based systems that produce systems, products, or services such as schools, hospitals, banking systems, and manufacturers. As such, they require insightful, efficient, and effective organizational structures, supporting assets, and collaborative interactions.  

Some systems require the analysis, design, and development of specialized structures, complex interactions, and performance monitoring that may have an impact on the safety, health, and wellbeing of the public as well as the environment, engineering of systems may be required. As you investigate WHAT is required to analyze, design, and develop both types of systems, you will find that they both share a common set concepts, principles, and practices. Business systems, for example, may require application of various analytical and mathematical principles to develop business models and performance models to determine profitability and return on investment (ROI) and statistical theory for optimal waiting line or weather conditions, for example. In the case of highly complex systems, analytical, mathematical, and scientific principles may have to be applied. We refer to this as the engineering of systems, which may require a mixture of engineering disciplines such as system engineering, electrical engineering, mechanical engineering, and software engineering. These disciplines may only be required at various stages during the analysis, design, and development of a system, product, or service.

This text provides the concepts, principles, and practices that apply to the analysis, design, and development of both types of systems. On the surface these two categories imply a clear distinction between those that require engineering and those that do not. So, how do you know when the engineering of systems is required?

Actually these two categories represent a continuum of systems, products, or services that range from making a piece of paper, which can be complex, to developing a system as complex as an aircraft carrier or NASA’s International Space Station (ISS). Perhaps the best way to address the question: What is system engineering?

What Is System Engineering?

Explicitly System Engineering (SE) is the multidisciplinary engineering of systems. However, as with any definition, the response should eliminate the need for additional clarifying questions. Instead, the engineering of a system response evokes two additional questions: What is engineering? What is a system? Pursuing this line of thought, let’s explore these questions further.

Defining Key Terms

Engineering students often graduate without being introduced to the root term that provides the basis for their formal education. The term, engineering originates from the Latin word ingenerare, which means “to create.” Today, the Accreditation Board for Engineering and Technology (ABET), which accredits engineering schools in the United States, defines the term as follows:

·       Engineering “[T]he profession in which knowledge of the mathematical and natural sciences gained by study, experience, and practice is applied with judgment to develop ways to utilize economically the materials and forces of nature for the benefit of mankind.” (Source: Accreditation Board for Engineering and Technology [ABET]) 

There are a number of ways to define System Engineering (SE), each dependent on an individual’s or organization’s perspectives, experiences, and the like. System engineering means different things to different people.

You will discover that even your own views of System Engineering (SE) will evolve over time. So, if you have a diver-sity of perspectives and definitions, what should you do? What is important is that you, program teams, or your organization:

1.                Establish a consensus definition.

2.                Document the definition in organizational or program command media to serve as a guide for all.

For those who prefer a brief, high-level definition that encompasses the key aspects of System Engineering (SE), consider the following definition:

·         System Engineering (SE) The multidisciplinary application of analytical, mathematical, and scientific principles to formulating, selecting, and developing a solution that has acceptable risk, satisfies user operational need(s), and minimizes development and life cycle costs while balancing stakeholder interests. 

This definition can be summarized in a key System Engineering (SE) principle:

System engineering BEGINS and ENDS with the User.

System Engineering (SE), as we will see, is one of those terms that require more than simply defining WHAT System Engineering (SE) does; the definition must also identify WHO/WHAT benefits from System Engineering (SE). The ABET definition of engineering, for example, includes the central objective “to utilize, economically, the materials and forces of nature for the benefit of mankind.”

Applying this same context to the definition of System Engineering (SE), the User of systems, products, and services symbolizes humankind. However, mankind’s survival is very dependent on a living environment that supports sustainment of the species. Therefore, System Engineering (SE) must have a broader perspective than simply “for the benefit of mankind.” System Engineering (SE) must also ensure a balance between humankind and the living environment without sacrificing either.

System Components and Characteristics 

A big system may be seen as a set of interacting smaller systems known as subsystems or functional units each of which have its defined tasks. All these work in coordination to achieve the overall objective of the system. System engineering requires development of a strong foundation in understanding how to characterize a system, product, or service in terms of its attributes, properties, and performance.  

As discussed above, a system is a set of components working together to achieve some goal. The basic elements of the system may be listed as:

·        

·        Resources  

·        Procedures  

·        Data/Information  

·        Intermediate Data  

Processes

Resources

Every system requires certain resources for the system to exist. Resources can be hardware, software or live-ware. Hardware resources may include the computer, its peripherals, stationery etc. Software resources would include the programs running on these computers and the live-ware would include the human beings required to operate the system and make it functional.

Thus these resources make an important component of any system. For instance, a Banking system cannot function without the required stationery like cheque books, pass books etc. such systems also need computers to maintain their data and trained staff to operate these computers and cater to the customer requirements.

Procedures

Every system functions under a set of rules that govern the system to accomplish the defined goal of the system. This set of rules defines the procedures for the system to Chapter 1 - Introduction to Systems operate. For instance, the Banking systems have their predefined rules for providing interest at different rates for different types of accounts.

Data/Information

Every system has some predefined goal. For achieving the goal the system requires certain inputs, which are converted into the required output. The main objective of the System is to produce some useful output. Output is the outcome of processing. Output can be of any nature e.g. goods, services or information.

However, the Output must conform to the customer's expectations. Inputs are the elements that enter the system and produce Output. Input can be of various kinds, like material, information, etc.

Intermediate Data

Various processes process system's Inputs. Before it is transformed into Output, it goes through many intermediary transformations. Therefore, it is very important to identify the Intermediate Data. For example, in a college when students register for a new semester, the initial form submitted by student goes through many departments. Each department adds their validity checks on it.

Finally the form gets transformed and the student gets a slip that states whether the student has been registered for the requested subjects or not. It helps in building the System in a better way. Intermediate forms of data occur when there is a lot of processing on the input data. So, intermediate data should be handled as carefully as other data since the output depends upon it.

Processes

The systems have some processes that make use of the resources to achieve the set goal under the defined procedures. These processes are the operational element of the system.

For instance in a Banking system there are several processes that are carried out. Consider for example the processing of a cheque as a process. A cheque passes through several stages before it actually gets processed and converted. These are some of the processes of the Banking system. All these components together make a complete functional system.

Systems also exhibit certain features and characteristics, some of which are:

·         Objective  

·         Standards  

·         Environment  

·         Feedback  

·         Boundaries and interfaces  

Objective

Every system has a predefined goal or objective towards which it works. A system cannot exist without a defined objective. For example an organization would have an objective of earning maximum possible revenues, for which each department and each individual has to work in coordination.

Standards

It is the acceptable level of performance for any system. Systems should be designed to meet standards. Standards can be business specific or organization specific.

For example take a sorting problem. There are various sorting algorithms. But each has its own complexity. So such algorithm should be used that gives most optimum efficiency. So there should be a standard or rule to use a particular algorithm. It should be seen whether that algorithm is implemented in the system.

Environment

Every system whether it is natural or man made co-exists with an environment. It is very important for a system to adapt itself to its environment. Also, for a system to exist it should change according to the changing environment. For example, we humans live in a particular environment. As we move to other places, there are changes in the surroundings but our body gradually adapts to the new environment. If it were not the case, then it would have been very difficult for human to survive for so many thousand years.

Another example can be Y2K problem for computer systems. Those systems, which are not Y2K compliant, will not be able to work properly after year 2000. For computer systems to survive it are important these systems are made Y2K compliant or Y2K ready.

Feed Back

Feedback is an important element of systems. The output of a system needs to be observed and feedback from the output taken so as to improve the system and make it achieve the laid standards. In fig 1.1, it is shown that a system takes input. It then transforms it into output. Also some feedback can come from customer (regarding quality) or it can be some intermediate data (the output of one process and input for the other) that is required to produce final output.

Boundaries and Interfaces

Every system has defined boundaries within which it operates. Beyond these limits the system has to interact with the other systems. For instance, Personnel system in an organization has its work domain with defined procedures. If the financial details of an employee are required, the system has to interact with the Accounting system to get the required details.

Interfaces are another important element through which the system interacts with the outside world. System interacts with other systems through its interfaces. Users of the systems also interact with it through interfaces. Therefore, these should be customized to the user needs. These should be as user friendly as possible.

Classifications of System 

From previous section we have a firm knowledge of various system components and its characteristics. There are various types of system. To have a good understanding of these systems, these can be categorized in many ways. Some of the categories are open or closed, physical or abstract and natural or man made information systems, which are explained next.  

Classification of systems can be done in many ways.

Physical or Abstract System

Physical systems are tangible entities that we can feel and touch. These may be static or dynamic in nature. For example, take a computer center. Desks and chairs are the static parts, which assist in the working of the center. Static parts don't change. The dynamic systems are constantly changing. Computer systems are dynamic system. Programs, data, and applications can change according to the user's needs.

Abstract systems are conceptual. These are not physical entities. They may be formulas, representation or model of a real system.

Open Closed System

Systems interact with their environment to achieve their targets. Things that are not part of the system are environmental elements for the system. Depending upon the interaction with the environment, systems can be divided into two categories, open and closed.

Open systems: Systems that interact with their environment. Practically most of the systems are open systems. An open system has many interfaces with its environment. It can also adapt to changing environmental conditions. It can receive inputs from, and delivers output to the outside of system. An information system is an example of this category.

Closed systems: Systems that don't interact with their environment. Closed systems exist in concept only.

Man made Information System

The main purpose of information systems is to manage data for a particular organization. Maintaining files, producing information and reports are few functions. An information system produces customized information depending upon the needs of the organization. These are usually formal, informal, and computer based.

Formal Information Systems: It deals with the flow of information from top management to lower management. Information flows in the form of memos, instructions, etc. But feedback can be given from lower authorities to top management.

Informal Information systems: Informal systems are employee based. These are made to solve the day to day work related problems. Computer-Based Information Systems: This class of systems depends on the use of computer for managing business applications. These systems are discussed in detail in the next section.

Information Systems 

In the previous section we studied about various classification of systems. Since in business we mainly deal with information systems we'll further explore these systems. We will be talking about different types of information systems prevalent in the industry.  

Information system deals with data of the organizations. The purposes of Information system are to process input, maintain data, produce reports, handle queries, handle on line transactions, generate reports, and other output. These maintain huge databases, handle hundreds of queries etc. The transformation of data into information is primary function of information system.

These types of systems depend upon computers for performing their objectives. A computer based business system involves six interdependent elements. These are hardware (machines), software, people (programmers, managers or users), procedures, data, and information (processed data). All six elements interact to convert data into information. System analysis relies heavily upon computers to solve problems. For these types of systems, analyst should have a sound understanding of computer technologies.

In the following section, we explore three most important information systems namely, transaction processing system, management information system and decision support system, and examine how computers assist in maintaining Information systems.

Types of Information Systems 

Information systems differ in their business needs. Also depending upon different levels in organization information systems differ. Three major information systems are  

1.                Transaction processing systems

2.                Management information systems

3.                Decision support systems

Figure 1.2 shows relation of information system to the levels of organization. The information needs are different at different organizational levels. Accordingly the information can be categorized as: strategic information, managerial information and operational information.

Strategic information is the information needed by top most management for decision making. For example the trends in revenues earned by the organization are required by the top management for setting the policies of the organization. This information is not required by the lower levels in the organization. The information systems that provide these kinds of information are known as Decision Support Systems.

Figure 1.2 - Relation of information systems to levels of organization

The second category of information required by the middle management is known as managerial information. The information required at this level is used for making short term decisions and plans for the organization. Information like sales analysis for the past quarter or yearly production details etc. fall under this category. Management information system (MIS) caters to such information needs of the organization. Due to its capabilities to fulfill the managerial information needs of the organization, Management Information Systems have become a necessity for all big organizations. And due to its vastness, most of the big organizations have separate MIS departments to look into the related issues and proper functioning of the system.

The third category of information is relating to the daily or short term information needs of the organization such as attendance records of the employees. This kind of information is required at the operational level for carrying out the day-to-day operational activities. Due to its capabilities to provide information for processing transaction of the organization, the information system is known as Transaction Processing System or Data Processing System. Some examples of information provided by such systems are processing of orders, posting of entries in bank, evaluating overdue purchaser orders etc.

Transaction Processing Systems

TPS processes business transaction of the organization. Transaction can be any activity of the organization. Transactions differ from organization to organization. For example, take a railway reservation system. Booking, canceling, etc are all transactions. Any query made to it is a transaction. However, there are some transactions, which are common to almost all organizations. Like employee new employee, maintaining their leave status, maintaining employee’s accounts, etc.

This provides high speed and accurate processing of record keeping of basic operational processes. These include calculation, storage and retrieval.

Transaction processing systems provide speed and accuracy, and can be programmed to follow routines functions of the organization.

Management Information Systems

These systems assist lower management in problem solving and making decisions. They use the results of transaction processing and some other information also. It is a set of information processing functions. It should handle queries as quickly as they arrive. An important element of MIS is database.

A database is a non-redundant collection of interrelated data items that can be processed through application programs and available to many users.

Decision Support Systems

These systems assist higher management to make long term decisions. These type of systems handle unstructured or semi structured decisions. A decision is considered unstructured if there are no clear procedures for making the decision and if not all the factors to be considered in the decision can be readily identified in advance.

These are not of recurring nature. Some recur infrequently or occur only once. A decision support system must very flexible. The user should be able to produce customized reports by giving particular data and format specific to particular situations.

Summary of Information Systems

Brief Introduction to System Analysis and Design 

Till now we have studied what systems are, their components, classification of system, information system. Now we will look into the different aspects of how these systems are built.  

Any change in the existing policies of an organization may require the existing information system to be restructured or complete development of a new information system. In case of an organization functioning manually and planning to computerize its functioning, the development of a new information system would be required.

The development of any information system can be put into two major phases: analysis and Design. During analysis phase the complete functioning of the system is understood and requirements are defined which lead to designing of a new system. Hence the development process of a system is also known as System Analysis and Design process. So let us now understand

1.                What exactly System Analysis and Design is?

2.                Who is system analyst and what are his various responsibilities?

3.                Users of the Systems?

What is System Analysis and Design? 

System development can generally be thought of having two major components: systems analysis and systems design. In System Analysis more emphasis is given to understanding the details of an existing system or a proposed one and then deciding whether the proposed system is desirable or not and whether the existing system needs improvements. Thus, system analysis is the process of investigating a system, identifying problems, and using the information to recommend improvements to the system.

Stages in building an improved system

The above figure shows the various stages involved in building an improved system.

System design is the process of planning a new business system or one to replace or complement an existing system.

Analysis specifies what the system should do. Design states how to accomplish the objective.

After the proposed system is analyzed and designed, the actual implementation of the system occurs. After implementation, working system is available and it requires timely maintenance. See the fugure above.

Role of System Analyst 

The system analyst is the person (or persons) who guides through the development of an information system. In performing these tasks the analyst must always match the information system objectives with the goals of the organization.  

Role of System Analyst differs from organization to organization. Most common responsibilities of System Analyst are following

1) System analysis 

It includes system's study in order to get facts about business activity. It is about getting information and determining requirements. Here the responsibility includes only requirement determination, not the design of the system.

2) System analysis and design: 

Here apart from the analysis work, Analyst is also responsible for the designing of the new system/application.

3) Systems analysis, design, and programming: 

Here Analyst is also required to perform as a programmer, where he actually writes the code to implement the design of the proposed application.

Due to the various responsibilities that a system analyst requires to handle, he has to be multifaceted person with varied skills required at various stages of the life cycle. In addition to the technical know-how of the information system development a system analyst should also have the following knowledge.

·                  Business knowledge: As the analyst might have to develop any kind of a business system, he should be familiar with the general functioning of all kind of businesses.

·                  Interpersonal skills: Such skills are required at various stages of development process for interacting with the users and extracting the requirements out of them

·                  Problem solving skills: A system analyst should have enough problem solving skills for defining the alternate solutions to the system and also for the problems occurring at the various stages of the development process.

Who are the Users of System (System end Users)? 

The system end users of the system refer to the people who use computers to perform their jobs, like desktop operators. Further, end users can be divided into various categories.  

Very first users are the hands-on users. They actually interact with the system. They are the people who feed in the input data and get output data. Like person at the booking counter of a gas authority. This person actually sees the records and registers requests from various customers for gas cylinders.

Other users are the indirect end users who do not interact with the systems hardware and software. However, these users benefit from the results of these systems. These types of users can be managers of organization using that system.

There are third types of users who have management responsibilities for application systems. These oversee investment in the development or use of the system.

Fourth types of users are senior managers. They are responsible for evaluating organization's exposure to risk from the systems failure.

Now we know what are systems and what is system analysis and design. So let us take a case in which we’ll apply the concepts we have learned in the chapter. The case would be referred to as and where necessary throughout the website and in this process we will be developing the system required.

Case Study: Noida Library System 

Noida Public Library is the biggest library in Noida. Currently it has about 300 members. Person who is 18 or above can become a member. There is a membership fee of Rs 400 for a year. There is a form to be filled in which person fills personal details. These forms are kept in store for maintaining members’ records and knowing the membership period.  

A member can issue a maximum of three books. He/she has three cards to issue books. Against each card a member can issue one book from library. Whenever a member wishes to issue a book and there are spare cards, then the book is issued. Otherwise that request is not entertained. Each book is to be returned on the specified due date. If a member fails to return a book on the specified date, a fine of Rs 2 per day after the due return date is charged. If in case a card gets lost then a duplicate card is issued. Accounts are maintained for the membership fees and money collected from the fines. There are two librarians for books return and issue transaction. Approximately 100 members come to library daily to issue and return books.

There are 5000 books available out of which 1000 books are for reference and can not be issued. Records for the books in the library are maintained. These records contain details about the publisher, author, subject, language, etc. There are suppliers that supply books to the library. Library maintains records of these suppliers.

Many reports are also produced. These reports are for details of the books available in the library, financial details, members’ details, and supplier’s details.

Currently all functions of the library are done manually. Even the records are maintained on papers. Now day by day members are increasing. Maintaining manual records is becoming difficult task. There are other problems also that the library staff is facing. Like in case of issue of duplicate cards to a member when member or library staff loses the card. It is very difficult to check the genuinity of the problem.

Sometimes the library staff needs to know about the status of a book as to whether it is issued or not. So to perform this kind of search is very difficult in a manual system.

Also management requires reports for books issued, books in the library, members, and accounts. Manually producing the reports is a cumbersome job when there are hundreds and thousands of records.

Management plans to expand the library, in terms of books, number of members and finally the revenue generated. It is observed that every month there are at least 50-100 requests for membership. For the last two months the library has not entertained requests for the new membership as it was difficult to manage the existing 250 members manually. With the expansion plans, the management of the library aims to increase its members at the rate of 75 per month. It also plans to increase the membership fees from 400 to 1000 for yearly and 500 for half year, in order to provide its members better services, which includes increase in number of books from 3 to 4.

Due to the problems faced by the library staff and its expansion plans, the management is planning to have a system that would first eradicate the needs of cards. A system to automate the functions of record keeping and report generation. And which could help in executing the different searches in a faster manner. The system to handle the financial details.

Applying the concepts studied in the chapter to the case study: 

The first thing we studied is systems. In our case study Noida Public Library is our system. Every system is a set of some functional units that work together to achieve some objective. The main objective of library system is to provide books to its members without difficulty. Fig 1.4 depicts our library system pictorially.

Our system has many functional units. Books issue and return section, books record unit, members record unit, accounts, and report generation units are the different functional units of the library. Each functional unit has its own task. However, each of these works independently to achieve the overall objective of the library.

Later in the session, we talked about different components and characteristics of the systems. Data is an important component of any system. Here, data is pertaining to the details of members, books, accounts, and suppliers. Since people can interact with the system this system is an open system. The system is mainly concerned with the management of data it is an information system.

If this system were to be automated as conceived by the management, then role of the system analyst would be to study the system, its workings, and its existing problems. Also the analyst needs to provide a solution to the existing problem.

Now that the management has decided for an automated system the analyst would perform the above tasks. As the analyst did the study of the system, the following problems were identified

·         Maintaining membership cards 

·         Producing reports due to large amount of data 

·         Maintaining accounts 

·         Keeping records for books in library and its members 

·         Performing searches 

Now that the analyst has studied the system and identified the problems, it is the responsibility of the analyst to provide a solution system to the management of the library.

Introduction to Systems: Summary and Review Questions 

Summary 

·                  A system is a set of interdependent components, organized in a planned manner to achieve certain objectives.

·                  System interacts with their environment through receiving inputs and producing outputs.

·                  Systems can be decomposed into smaller units called subsystems.

·                  Systems falls into three categories

·                  Physical or Abstract systems

·                  Open or closed system depending upon their interaction with environment.

·                  Man-made such as information systems.

·                  Three levels of information in organization require a special type of information.

·                  Strategic information relates to long-term planning policies and upper management.

·                  Managerial information helps middle management and department heads in policy implementation and control.

·                  Operational information is daily information needed to operate the business.

·                  Information systems are of many types. Management Information, transaction processing, and decision support systems are all information systems.

·                  Transaction processing system assist in processing day to day activities of the organization

·                  Management information systems are decisions oriented. These use transaction data and other information that is developed internally or outside the organization.

·                  Decision support systems are built for assisting managers who are responsible for making decisions.

·                  System analysis and design refers to the application of systems approach to problem solving.

Review Questions

1.                Define the term ‘System’.

2.                What are the various elements of system?

3.                Identify two systems in your surroundings.

4.                What is system analysis and design?

5.                What are the roles of system analyst?

6.                Make a list of traits that a system analyst should have.

7.                Will the responsibility of a system analyst vary according to:

(a) Organization size( for example small or large business)?
(b) Type of organization (business, government agency, non-profit organization)?

8.                Differentiate between

a) Open and closed system
b) Physical and abstract

9.                Main aim of an information system is to process _________.

10.             Transaction processing, __________________ , and decision support system are three types of information system.

11. State true or false
    
    a) Decision support system is for middle level management.
    b) Closed systems don't interact with their environment.
    c) Transaction processing system handles day-to-day operations of the organization.
    d) Management information system deals with strategic information of organization.
    e) Problem solving and interpersonal skills are desirable for system analyst.