Download System Analysis and Design: Principles, Processes, and Challenges and more Lecture notes Systems Design in PDF only on Docsity!
UNIT –I
System Analysis is the application of the system approach to problem solving using computers. Organizations are a complex system that consists of inter-related and interlocking sub-system. Changing one part of system have both anticipated and unanticipated consequences on the other part of system.
System Analysis & Design Focus On System Processes And Technology.
System Analysis and design for information system were bounded in general system theory which emphasis on a close look at all parts of a system. In general, System theory is concerned with “developing a systematic theoretical framework upon which to make decision”. A system is a way of thinking about organization and their problem. It also involves a set of techniques that helps in solving problem.
System Definition : - It comes from Greek word means organized relationship among function units or components Or Orderly grouping of inter-dependent components. A system exists because it is designed to achieve one or more objective. A system is an orderly grouping of interdependent component linked together according to a plan to achieve a specific objective. The component may be simple or Complex.
Implements Of System Concepts
1. System must be designed to achieve a pre-determined objectives.
2. Inter-relationship & inter-dependence must exist among the component.
3. The objectives of the organization as a whole have higher priority than the objectives of its sub-
system.
Characters Of A System
1. Organization :- Arrange form of system.
2. Interaction :- B/w components of system.
3. Inter-dependence :- of components on each other.
4. Integration :- Binding of System.
5. Central Objective :- Main Purpose of System.
Organization
Implies structure and order. It is the arrangement of components that helps to achieve objectives. In the design of a business system for e.g. the hierarchical relationships starting with the president on top and leading downward to the blue-collar workers represents the organization system. Such an arrangement portrays a system-sub-system relationship, defines the authority structure specifies the formal flow of communication and formalizes the chain of command.
Interaction
Refers to the manner in which each component, function with other component of the system. In computer System, the central processing unit must interact with the input devices to solve the problem. In turn the main memory holds programs & data that the arithmetic unit uses for computation. The inter-relationship between these components enables the computer to perform.
Inter-dependence
Means that part of organization or computer system depend on one another. They are coordinated and linked together according to a plan. One subsystem depends on the output of another subsystem for proper functioning. i.e. the output of one subsystem is the required input for the another subsystem. In summary, no subsystem can function in isolation because it is dependent on the data (input) it receives from other subsystem to perform its required tasks.
Integration
Refers to the holism of system. Integration is concerned with how a system is tied together. It is more than sharing a physical part or location. It means that part of system work together within the system even though each part performs a unique function.
Central Objective
May be real or stated. Although a stated objective may be the real objective. The important point is that users must know the central objective of a computer application early in the analysis for a successful design and conversion. The analyst must work around such obstacles to identify the real objective of the proposed changes.
Elements Of A System
Following are the elements of a well system :-
1. Output & Inputs
2. Processors
3. Control
4. Feedback
5. Environment
6. Boundaries & Interface
Output & Inputs
A major objective of a system is to produce an output that has value to its user. Inputs are the elements (material, human resources, information) that enter the system for processing. Output is the outcome of processing. A system feeds on input to produce output. It is important to point out that determining the output is a first step in specifying the nature, amount and regularity of the input needed to operate a system. For e.g. the system analysis, the first concern is to determine the user’s requirements to a proposed computer system- that is, specification of output that the computer is expected to provide for meeting users requirements.
Processor(s)
Abstract system are conceptual and non physical entities. They may be as straight forward as formula’s or relationships among set of variables or models the abstract conceptualization of physical situation. A model is representation of a real or planned system. the use of model makes it easier for analyst to visualize relationships in the system under study. The objective is to point out the significant element and the key inter-relationships of a complex system.
Open or Closed System
Based on their degree of independence. An open system has many interfaces with its environment. It permits interaction across its boundary. It receives the input from and deliver outputs to the outside. An information system falls into this category, since it must adopt to the changing demands of the user. A closed system is isolated from the environment influence. In reality, a completely closed system is rare. In system analysis, organizations applications and computers are invariably open, dynamic systems influenced by their environment.
Characteristics of Open System
Input from Outside Open System are self adjusting and self regulating. When functioning properly, an open system reaches a steady state or equilibrium. In a retail firm for e.g. a steady state exists when goods are purchased and sold without being either out of stack or overstocked. An increase in the cost of good forces a comparable increase in price or decrease in operating cost. This response gives the firm its steady state.
Entropy All dynamic system tend to run down overtime resulting in entropy or loss of energy. Open system resist entropy by seeking new inputs or modifying the processes to return a steady state.
Process, output & cycles Open Systems produce useful output and operate in cycles, following a continuous flow path.
Differentiation Open Systems have a tendency towards an increasing specialization of functions and a greater differentiation of their components. In business, the role of people and machines tends towards greater specialization and greater interaction.
Equaifinality The term implies that goals are achieved through differing courses of action and a variety of paths. In most system there is more of a consensus on goals than on path to reach the goal.
Man Made Information System
An Information system is the basis for interaction between the user and the analyst. It provides instructions, commands and feedback. It determines the nature of relationships among decision makers. An information system may be defined as a set of devices, procedures and operating systems designed around user based criteria to produce information and communicate it to the user for planning control and performance. The major information system is formal, informal and computer based.
Formal Information System
It is based on the organization represented by the organization chart. The chart is a map of position and their authority relationships, indicated by boxes and connected by lines (straight). It is concerned with the pattern of authority, communication and workflow. Information is formally disseminated in instruction, memos or reports from top management to the intended user in the organization. This structure also allows feedback up the chain of command for follow up.
Informal information system : - it is an employee based system designed to meet personnel and vocational needs and to help solve, work-related problems. It is a useful system because it works within the frame work of business and its stated policies. The analyst should have knowledge of the chain of command, the power authority influence network and how decisions are made to get a feel for how much support can be expected for a prospective installation. The knowledge of about the inner working of the employee based system is useful during the exploratory phase of analysis. A proper interface with the informal communication channels could mean the difference between the success and failure of new system Computer based Information System It relies on computer for handling business application. The computer is now a required source of information. System analysis relies heavily on computer for problem solving. This suggests that the analyst must be familiar with computer technology and have experience in handling people in an organizational context.
System Models
A Model is the abstract conceptualization of physical situation. A model is a representation of a real or a planned system. The use of model makes it easier for the analyst to visualize relationships in the system under study. The objective is to point out the significant elements and the key interrelationships of a complex system. The analyst begins by creating a model of reality (facts, relationships, procedures etc.) with which the system is concerned. Every computer system deals with the real world, a problem area, or a reality outside itself. The major models are :-
Schematic Models A Schematic model is a two-dimensional chart depicting system elements and their linkage. It shows the major elements of information system together with material and information flow.
Flow System Model A flow system model shows the flow of material energy, and the information that hold the system together. There is an orderly flow of logic in such models. a widely known e.g. is PERT (Program Evaluation & Review Technique). It is used to abstract a real world system in model form, manipulate specific values to determine the crucial path, interpret the relationships and relay them back as a control.
Static system Model This type of model exhibits one pair of relationships such as activity time or cost quantity. The Gantt Chart for e.g. gives a static picture of an activity time relationship. The planned activities (Stamping, sanding etc.) are plotted in relation to time. The date column has light lines that indicate the amount of time it takes to complete a given activity. The heavy lines represents the cumulative time schedules for each activity. The broken lines indicates that the department is two days behind schedule. The arrowhead indicates the date when the chart is to be in effect.
Dynamic System Model Business organization are dynamic systems. A dynamic model approximates the type of organization or applications that analyst deals with. It depicts an ongoing constantly changing systems. As mentioned earlier it consists of
1. Inputs that enter the system.
2. Processor through with transformation occurs.
3. the programs required for processing
4. the output that result from processing.
Categories Of Information
To understand system development, we need to recognize that a candidate system has a life cycle, much like a living system or a new product. Systems analysis and design are based to the system life cycle. The stages are described below. The analyst must progress from one stage to another methodically, answering key questions and achieving results in each stage.
Recognition of Need
One must know what the problem is before it can be solved. The basis for a candidate system is recognition of a need for improving an information system or a procedure. For example, a supervisor may want to investigate the system flow in purchasing. Or a bank president has been getting complaints about the long lines in the drive – in. This need leads to a preliminary survey or an initial investigation to determine whether an alternative system can solve the problem. It entails looking into the duplication of effort bottlenecks, inefficient existing procedures, or whether parts of the existing system would be candidates for computerization.
If the problem is serious enough, management may want to have an analyst look at it, such an assignment implies a commitment, especially if the analyst hired from the outside.
Impetus for system change
The idea for change originates in the environment or from within the firm. Environment based
ideas originates from customers vendor, government sources etc. for e.g. New Employment
compensation regulation may make it necessary to change the reporting procedure format and content
of various report, as well as file structure. Customer complaints about the delivery of orders may
prompt an investigation of delivery schedule, an experience of truck driver or the volume of orders to
be delivered.
When investigated each of these ideas may lead to a problem definition as a first step in the system
life cycle process.
Users originated ideas also prompt initial investigation. To what extent and how quickly a user-
originated idea is converted to a feasibility study depend on several factor :-
1. The risks and potential returns
2. Managements bias towards users
3. Financial costs and the funds available for system work
4. Priorities of other project in the form.
5. The persuasive ability of the user.
A system analyst is in a unique position to detect and even recommend change. The role and status of
the analyst as a professional add credibility to the suggestions made.
Feasibility Study
A feasibility study is a test of a system proposal according to its workability impact on the organization, ability to meet user needs, and effective use of resources. It focuses on there major questions:
i. What are the user’s demonstrable needs and how does a candidate system meet them?
ii. What resources are available for given candidate systems? Is the problem worth solving?
iii. What are the likely impacts of the candidate system on the organization? How will it fit within the organization’s master MIS plan?
The objective of a feasibility study is not to solve the problem but to acquire a sense of its scope. During the study, the problem definition is crystallized and aspects of the problem to be included in the system are determined. Consequently, costs and benefits are estimated with greater accuracy at this stage.
The result of the feasibility study is a formal proposal. This is simply a report - a formal document detailing the nature and scope of the proposed solution. The proposal summarizes what is known and what is going to be done. It consists of the following.
- Statement of the Problem – a carefully worded statement of the problem that led to analysis.
- Summary of Findings and Recommendations – a list of the major findings and recommendations of the study. It is ideal for the user who required quick access to the results of the analysis of the system under study. Conclusions are stated, followed by a list of the recommendations and a justification for them.
- Details of Findings – An outline of the methods and procedures undertaken by the existing system, followed by coverage of objectives & procedures of the candidate system. Included are also discussions of output reports, file structures, and costs and benefits of the candidate system.
- Recommendations and Conclusions – special recommendations regarding the candidate system, including the personal assignments costs, project schedules, and target dates.
After the proposal is viewed by management it becomes a formal agreement that paves the way for actual design and implementation. This is a crucial decision point in the life cycle. Many projects die here, whereas the more promising ones continue through implementation. Changes in the proposal are made in writing, depending on the complexity, size, and cost of the project. It is simply common sense to verify changes before committing the project to design.
Analysis
It is a detailed study of the various operations performed by the system and their relationship within and outside of the system. A key question is – what must be done to solve the problem? One aspect of analysis is defining the boundaries of the system and determining whether or not a candidate system should consider other related systems. During analysis, data are collected on available files, decision points, and transactions handled by the present system Data flow diagrams, system models and tools that are used, interviews, on site observations and questionnaires are e.g. Training, experience and common sense are required for collection of information needed to do analysis. Once analysis is completed, the analyst has a firm understanding of what is to be done. The next step is to decide how the problem might be solved. Thus in system design, we move from the logical to the physical aspects of life cycle.
Design
The most creative and challenging phase of the system life cycle is system design. The term design describes both a final system and a process by which it is developed. It refers to the technical specifications (analogous to the engineer’s blueprints) that will be applied in implementing the candidate system. It also includes the constructions of programs and programme testing. The key question here is – How should the problem be solved The first step is to determine how the output is to be produced and in what format. Samples of the output (and input) are also made available. Second, input data and master files (data base) have to be designed to meet the requirements of the proposed output. The operational (processing) phase are handled through program construction and testing, including a list of the programmes needed to meet the system’s objectives and complete documentation.
The final report prior to the implementation phase includes procedural flowcharts, record layouts, report layouts, and a workable plan for implementing the candidate system. Information on personnel, money,
The demand is made up of following :-
1. Operations of existing systems
2. Maintenance that focuses on “Patching Program”
3. Enhancements that involve major modifications in program structure or equipment.
4. Request for candidate system.
All these demand requires
1. Computer operators to run equipment.
2. Data entry personnel
3. System analysts to define and design specification
4. Application programmers to convert system specifications to computer program
5. Maintenance programmers to repair errors
6. Supervisors, project leader and managers to coordinate the jobs with the user.
Favour Of One Project Over Another
Depends on technical, behavioral and Economic factors.
Technical Factor Involves the system departments ability to handle a project. Much depend on availability of qualified analysts, designers and software specialist to do work. The cost of developing the project has to be weighed against the total benefits expected.
Behavioral Factors
Involves the users past experience with an existing system, the success record of the analyst and the influence the user can exert on upper management to finance a candidate system.
Economic Factor It is the most important criterion in selecting a project. It focuses on the systems potential return on investment. What is considered an acceptable rate varies with different formulas, the variable chosen and the like.
Political Consideration Politics is the art of using influence and building coalitions. When routine procedures do not achieve the right results. When system projects are developed, a collaborative relationship with the end user is helpful. A user who participated in building a system rarely criticizes it. If such a participative relationship comes too late, resistance can crop up and politics come into play. The trick is to anticipate resistance early and turn it into support.
Prototyping In system development there are two major problems with building information system:-
1. The system development cycle takes too long.
2. The right system is rarely developed in the first time.
Lengthy development frustrates the user. An analyst seems to get bogged down with tedious methodologies for developing system. it usually turns out that what users ask for is not what they want and what they want is not what they need.
An alternative to this “Paralysis by analysis” is an advanced technique called prototyping. Prototyping recognizes problems to cognitive style and uses advanced computer technology. It advocates building a simple system through trial and error and refining it through an iterative process. The most extensive research on prototyping has been conducted by Neumann and Jenkins. The basic steps are:-
1. Identify the user’s information and operating requirements.
2. Develop a working prototype that focuses on only the most important functions, using a basic
database.
3. Allows the user to use the prototype, discuss requested changes and implement the most important
change.
4. Repeat the next version of prototype with further changes in corporate until the system fully meets
user requirements. The benefit include shorter development time more accurate user requirements and greater user participation and support.
The Role Of System Analyst
The role requires a combination of skill experience, personality and common sense. He / She plays a major role in seeing business benefits from computer technology. The analyst is a person with unique skills.
Definition
Random House Dictionary = A person who conduct a methodical study and evaluation of an activity such as a business to identify its desired objectives in order to determine procedures by which these objectives can be gained. The four key steps in scientific Management
1. Develop an ideal method of doing a task and establish a standard for it. In turn worker should be
paid an incentive for exceeding the STD.
2. Select the best person for the job and train him / her accordingly.
3. Incorporate the scientific method with well-trained people.
4. Establish cooperation between manager and worker based on division of labor.
What A System Analyst Does
A system analyst carries out the following job:
(a) The First and perhaps most difficult task of systems analyst is problem definition. Business problems are quite difficult to define. It is also true that problems cannot be solved until they are precisely and clearly defined.
(b) Initially a systems analyst does not know how to solve a specific problem. He must consult with managers, users and other data processing professionals in defining problems and developing solutions. He uses various methods for data gathering to get the correct solution of a problem.
(c) Having gathered the data relating to a problem, the systems analyst analyses them and thinks of plan to solve it. He may not come up personally with the best way of solving a problem but pulls together other people's ideas and refines them until a workable solution is achieved.
(d) Systems analysts coordinate the process of developing solutions. Since many problems have number of solutions, the systems analyst must evaluate the merit of such proposed solutions before recommending one to the management
(e) Systems analysts are often referred to as planners. A key part of the systems analyst's job is to develop a plan to meet the management's objectives.
(f) When the plan has been accepted, systems analyst is responsible for designing it so that management's goal could be achieved. Systems design is a time consuming, complex and precise task.
(g) Systems must be thoroughly tested. The systems analyst often coordinates the testing procedures and helps in deciding whether or not the new system is meeting standards established in the planning phase.
What Does It Take To Do System Analysis
The analyst skill may be divided into two categories :-
- Inter-personnel Skill :- this skill deals with relationship and the interface of the analyst with people in business.
Systems analyst must have the following attributes
(a) Knowledge of people : Since a systems analyst works with others so closely, he or she must understand their needs and what motivates them to develop systems properly.
(b) Knowledge of Business functions : A systems analyst must know the environment in which he or she works. He must be aware of the peculiarities of management and the users at his installation and realize how they react to systems analyst. A working knowledge of accounting and marketing principles is a must since so many systems are built around these two areas. He must be familiar with his company's product and services and management's policies in areas concerning him.
(c) Knowledge of Data processing principles : Most systems today are computer based. The systems analyst must fully aware about the potential and limitations of computers.
(d) Ability to communicate : As a coordinator, a systems analyst must communicate properly with people of different levels within an organization. Systems analyst must listen carefully to what others say and integrate the thoughts of others into the systems development process.
(e) Flexibility : Systems analysts must be flexible in their thinking since they often do not get-their own way. Different factions in an organization have conflicting needs and most systems are the result of compromise. The analyst's goal is to produce the system that will be the best for the organization. This requires an open mind and flexibility in his ideas.
(f) An analytical mind : It takes an unusual person to see through problems facing an organisation and develop solutions that will work. Systems analysts often find themselves with more data than they can cope with. It requires an analytical mind to select pertinent data and concentrate on them in defining problems and forming solutions.
(g) Well educated with sharp mind : Systems analysts are called upon to work with people at all levels virtually in every aspect of business. They must know how to work with all of them and gain their confidence. Analysts must have sharp mind to learn quickly how people do their jobs and develop ways for them to do it better.
The Multifaced Role Of Analyst
- Change Agent :- The analyst may be viewed as an agent of change. A candidate system is designed to introduce change and re-orientation in how the user organization handles information or makes decision. In role of a changing agent, the system analyst may select various styles to introduce change to the user organization. The styles range from that of persuader (the middles form of intervention ) to the imposer (the most severe intervention). On the other hand when drastic changes are required, it may be necessary to adopt the confronter or even the imposer style. No matter what style is used, however, the goal is same; to achieve acceptance of candidate system with a minimum of resistance.
- Investigator and Monitor :- in defining a problem the analyst determine why the present system does not work well and what changes will correct the problem. As Investigator analyst extract the real problem from existing system and create information structures that uncover previously unknown trends that may have a direct impact on organization. To understand and successfully complete a project the analyst must monitor programs in relation to time, cost and quality of these resources, time is the most important. Implementation delays also mean the system will not be ready on time, which frustrates users and customers alike.
- Architect :- The Architects primary function as license between the clients abstract design requirements and the contractor. As architect, the analyst also creates a detailed physical design of candidate system. He / She aids user in formalizing abstract ideas and provides details to build the end product i.e. the candidate system.
- Psychologist :- The analyst play the role of psychologist in the way He / She reaches people, interpret their thoughts, assesses their behavior and draw conclusion from these interaction. Understanding inter- functional relationship is necessary and important. It is important that the analyst be aware of peoples feelings and be prepared to get around things in a graceful way. The art of listening is important in evaluating responses and feedback.
- Sales Person :- Selling change can be as crucial as initiating change. The oral presentation of system proposal has one objective – selling the user on system. Selling the system actually takes place at each step in the system life cycle, however sales skill and persuasiveness , then are crucial to success of system.
- Motivator :- A candidate system must be well designed and acceptable to the user. The analyst role as a motivator becomes obvious during the first few weeks after implementation and during times when turnover results in new people being trained to do work with candidate system.
- Politician :- In implementing a candidate system, the analyst tries to appease all parties involved. In as much as a politician must have the support of his / her constituency , so is the analyst’s goal to have the support of the user’s staff. He / She represents their thinking and tries to achieve their goals through computerization. In Summary the Analysts are usually factual and “ down to earth’s” and see the world as logical orderly & predictable. They prefer to concentrate on an objective data, seek the best method and be highly prescriptive. They appear to be cool and studious.
The Analyst User Interface
An important aspect of system development is a viable interface between the analyst and the user. Analyst must devote as much skill and effort to achieve a productive relationship with the user as they devote to the technical requirements of system. As the number of users increases the probability of system failure increases without close analyst / user interface.
