System Analysis and Design (Overview)

System Analysis and Design


System analysis and design refers to the process of examining a business situation with the intent of improving it through better procedures and methods.

System development can have two major components:

1.    System Analysis:

ü System analysis is the process of gathering and interpreting facts, diagnosing problems and using the information to recommend improvement to the system.

ü We can say that analysis specifies what the system should do.

 2.    System Design:

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

ü Before planning can be done, we must thoroughly understand the existing system and determine how computers can best be used to make its operation more effective.

ü Design states how to accomplish the objective.

What is System Approach?

ü The System Approach shows a set of procedure for solving a particular problem.

ü It applies scientific methods to observe, clarify, identify, and solve a problem with special care being taken to understand the inter-relatedness between element and their system  characteristics.

What is System?

System is derived from the Greek word systema, which means an organized relationship among the functioning units or components.


A System is an orderly grouping of interdependent components linked together according to a plan to achieve a specific goal.

Component may refer to physical parts, managerial steps (Planning, organized, controlling) or a subsystem in a multi-level structure.

Each component is part of the total system and has to do its own share of work for the system to achieve the desired goal.

Example of System:

·       Transportation System

·       The Communication System

·       The Accounting System

·       The Production System

·       The Economic System

·       The Computer System


What is System study?

  • System study may be defined as “a study of the operations of a set of connected elements and of the inter-connections between these elements”.

What is the basic different between System Approach and System Analysis?

  • System Approach shows a set of procedure for solving a particular problem.
  • System Analysis is a management technique which helps in designing a new system improving an existing system or solving a system problem.

Characteristics of a System

Following characteristics are present in all system:

a)   Organization: Organization implies structure and order. It is the arrangement of components that helps to achieve objectives.

b)    Interaction: Interaction refers to the procedure in which each component function with other components of the system. 

 c)    Interdependence: Interdependence means that component of the organisation or computer system depend on one another. They are coordinated and linked together in a planned way to achieve an objective. 

d)   Integration: Integration is concerned with how a system is tied together. 

e)    Central ObjectiveEvery system has a goal or a central objective. The goal provides the reason for the existence of the system.

Elements of System Analysis

There are four basic elements in system analysis:

a)    Outputs:

b)    Inputs: 

  • Accuracy-
  • Timeliness-
  •  Proper format-
  • Economy-

c)    Files:

d)    Processes:

Types of System

Systems have been classified in different ways:

i)               Physical or Abstract Systems:

Physical systems are real and tangible. It is possible to touch and feel a physical system. Abstract systems are conceptual. Abstract systems are generally models of physical reality.


Physical Systems

Abstract Systems


Design of Car


Blueprint of a building


Newton’s laws of classical mechanics

Accounts Department

Double entry accounting system


Positional number system


Boolean Algebra




ii)             Open or Closed Systems

An open system interacts with its environment. It receives input from the environment and provides output to the environment. Most systems are open systems.

 A closed system does not interact with the environment. Closed systems normally get destroyed due to entropy.

 (iii) Natural v/s Man-Made systems

A system may be classified as either natural or man-made. Natural systems are created by the nature. Manufactured System is the man-made system.


Natural Systems

Man-Made Systems

Solar System


Human Body





(iv) Deterministic or Probabilistic Systems

A deterministic system is one in which the occurrence of all events is perfectly predictable. An example of such a system is a numerically controlled machine tools.

 Probabilistic system is one in which the occurrence of events cannot be perfectly predicted. The exact output is not known.  An example of such a system is a warehouse and its contents.

 (v) Man-made Information Systems:

It is generally believed that information reduces uncertainty about a state or event.

It is an interconnected set of information resources to manage data for particular organization, under Direct Management Control (DMC). 

This system includes hardware, software, communication, data, and application for producing information according to the need of an organization.

The major information systems are:

a.     Formal Information Systems

b.    Informal Information Systems

c.     Computer Based Information Systems (CBIS)

                                                 i.     Transaction Processing Systems (TPS)

Substitute computer-based processing for manual procedures. Deals with well structured routine processes. Includes record-keeping application

ii.     Management Information Systems (MIS)

Provides input to be used in the managerial decision process. Deals with supporting well-structured decision situations. Typical information requirements can be anticipated.

iii.     Decision Support System (DSS)

Provides information to managers who make judgements about particular situations. Supports decision makers in situations that are not well structured.

                                                 iv.     Office Automation System (OAS)

It is a multi-function, integrated computer based system, that allows many office activities to be performed in an electronic mode.

System Development Life Cycle (SDLC)

The Systems Development Life Cycle consists of the following activities:

1)    Preliminary Investigation: This activity has three parts-

a.     Request clarification

b.    Feasibility Study: There are three aspect in the feasibility study portion of the
preliminary investigation-

                                                i.     Technical Feasibility

                                                ii.     Economic Feasibility

                                              iii.     Operational Feasibility

c.     Request Approval

2)    Determination of System Requirements

3)    Design of System

4)    Development of Software

5)    System Testing

6)    Implementation

7)    Evaluation: The actual evaluation can occur along any of the following dimensions:

i)               Operational Evaluation

ii)            Organizational Impact

iii)          User Manager Assessment

iv)           Development Performance

8)    Maintenance

Data Flow Diagrams:

Data Flow Diagram is a graphical modelling tool. It can be used to create the process
model for an information system.

Graphical description of a system’s data and how the processes transform the data is
known as DFD.

DFDs are made using four kinds of components. Processes, Data Stores, External Entities and Data Flows.

These components are represented using graphical symbols.

DFD Diagram Notations (Symbols):

 Rules for construction of DFD


1.   Arrow should not cross each other

2.   Rectangle, Circle, and files must bear name

3.   Decomposed data flows must be balanced (all data flows on the decomposed diagram must reflect flows in the original diagram).

4.   No two data flows, rectangle, or circles can have the same name.

5.   Draw all data flows around the outside of the diagram.

6.  Choose meaningful for data flows, processes, and data stores. Use strong verbs followed by nouns.

7.   Control information such as record counts, passwords, and validation requirements are not pertinent to a data-flow diagram.


What is a Computer Based Information System?

System analysts develop several different types of information systems which depend mainly on the computers for handling business applications. This class
of systems is known as Computer Based Information systems.

When is a decision considered to be unstructured?

A decision is considered unstructured if there are no clear procedures for making the decision.

What are the four basic elements in System Analysis?

The four basic elements in system analysis are: Outputs, Inputs, Files and Processes.

Who is System Analyst?

A System analyst is a person who conducts a study, identifies activities and objectives and determines a procedure to achieve the objectives.

 Role of systems Analyst (What a System Analyst does?)

A system analyst carries out the following job-

ü The first and perhaps most difficult task of system analyst is problem definition. System Analyst precisely and clearly define business problems.

 ü Initially a system analyst does not know how to solve a specific problem. He must consult with manager, users and other data processing professionals in defining problems and developing solutions.

 ü Having gathered the data relating to a problem, the systems analyst analysis them and thinks of plan to solve it.

 ü System Analysts coordinate the process of developing solutions.

 ü System analyst are often referred to as planners.

 ü When the plan has been accepted, system analyst is responsible for designing it so that management’s goal could be achieved.


What are the Attributes of an effective System Analyst?

There are many attributes a system analyst should have.

Some of which are-

(a)  Knowledge of people

(b) Knowledge of Business Function.

(c)  Knowledge of Data Processing Principles

(d) Ability to Communicate

(e)  Flexibility 

(f)   An Analytical Mind

(g) Well educated with sharp mind

What do you mean by feasibility? What is feasibility study?

Feasibility is the determination of whether or not a project is worth doing.

The process followed in making this determination is called a feasibility study.

Feasibility study determines if a project can and should be done.

What are the seven types of feasibility?

The seven types of feasibility are:

ü Technical feasibility

ü Operational feasibility

ü Economic feasibility

ü Social feasibility

ü Management feasibility

ü Legal feasibility and,

ü Time feasibility





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