System Analysis and Design

Nature of Systems and

System Analysis Concepts

Definition of System • Systems are created to solve

problems.

• One can think of the systems

approach as an organized way of

dealing with a problem.

• In this dynamic world, thus System

Analysis and Design (SAD), mainly

deals with the software development

activities.

Definition of System • A collection of components that work together

to realize some objectives forms a system. Basically there are three major components in every system, namely input, processing and output.

Fig. 1.1: Basic System Components

• The objective of the system demands that some output is produced as a result of processing the suitable inputs.

• A well-designed system also includes an additional element referred to as ‘control’ that provides a feedback to achieve desired objectives of the system.

• In a system the different components are connected with each other and they are interdependent. For example, human body .

• It Represents a complete natural system.

• We are also bound by many national systems such as political system, economic system, educational system and so forth.

Other Examples

• For example, consider an automatic car wash.

• Tangible inputs for the process are a dirty car, water, and various cleaning ingredients.

• Time, energy, skill, and knowledge also serve as inputs to the system because they are needed to operate it.

• The Processing mechanisms consist of first selecting which cleaning option you want (wash only, wash with wax, wash with wax and hand dry, etc.) and communicating that to the operator of the car wash.

• A feedback mechanism is your assessment of how clean the car is.

• Liquid sprayers, shoot clear water, liquid soap, or car wax depending on where your car is in the process and which option you selected

Other Examples

• The output is a clean car.

• As in all systems, independent elements or components (the liquid sprayer, foaming brush, and air dryer) interact to create a clean car.

Other Examples

Elements of System

• In most cases, systems analysts operate in

a dynamic environment where change is a

way of life. The environment may be a

business firm, a business application, or a

computer system. To reconstruct a system,

the following key elements must be

considered:

Elements of System 1.Outputs and inputs.

2.Processor(s).

3.Control.

4.Feedback.

5.Environment.

6.Boundaries and interface

Elements of System 1.Outputs and inputs

• Inputs are the elements (material, human resources, and information) that enter the system for processing. Output is the outcome of processing.

2. Processor(s)

• Involves the actual transformation of

input into output. It is the operational component of a system. Processors may modify the input totally or partially, depending on the specifications of the output.

Elements of System

3. Controls

• In a computer system, the operating system and accompanying software influence the behavior of the system. Output specifications determine what and how much input is needed to keep the system in balance.

Elements of System

4. Feedback • Feedback may be positive or negative,

routing or informational. • Positive feedback reinforces the

performance of the system. It is routine in nature.

• Negative feedback generally provides the controller with information for action.

• In systems analysis, feedback is important in different ways.

Elements of System

5.Environment

• The environment is the “suprasystem” within which an organization operates.

• It is the source of external elements that impinge on the system. In fact, it often determines how a system must function.

• For example, the organization’s environment, consisting of vendors, competitors, and others, may provide constraints and, consequently, influence the actual performance of the business.

Elements of System

6.Boundaries and Interface

• A system should be defined by its boundaries – the limits that identify its components, processes and interrelationship when it interfaces with another system.

Elements of System

Types of System 1. Physical or abstract systems.

2. Open or closed systems.

3. 'Man-made' information systems.

4. Formal information systems

5. Informal information systems

Types of System 1. Physical System

• Physical systems are tangible entities that may be static or dynamic in operation.

• For example, the physical parts of the computer center are the officers, desks, and chairs that facilitate operation of the computer.

Types of System 2. Open or Closed System Open System • It permits interaction across its

boundary; it receives inputs from and delivers outputs to the outside.

• An information system falls into this category, since it must adapt to the changing demands of the user.

Types of System 2. Open or Closed System

Close System

• In contrast, a closed system is isolated from environmental influences.

Types of System 3. Man Made System • An information system is the basis for

interaction between the user and the analyst. It provides instruction, commands and feedback. It determines the nature of the relationships among decision-makers. In fact, it may be viewed as a decision center for personnel at all levels.

Types of System 4. Formal Information System

-Organizational Representation

5.Informal Information System

- Employee based system

• Information System, Plays vital role in the business and operations, enterprise collaboration and management, and strategic success of business that must operate in an internetworked global environment.

Business System / Information System

Analysis - Definition

• Analysis is the process of breaking a complex topic or substance into smaller parts to gain a better understanding of it.

Analysis • Characteristics The purpose of analysis in the planned change

process is to facilitate decision-making. Analysis clarifies the nature and dynamics of

the change opportunity and the relevance of possible responses.

However, it is not realistic to expect analysis to

provide “the answer”

System Analysis

• It is the process of collecting factual data, understand the processes involved, identifying problems and recommending feasible suggestions for improving the system functioning.

System Analysis

• It attempts to give birth to a new efficient system that satisfies the current needs of the user

• The result of this process is a logical system design.

• Systems analysis is an iterative process that continues until a preferred and acceptable solution emerges

Purpose of System Analysis

• Studying the business processes

• Gathering operational data

• Understand the information flow

• Finding out bottlenecks and evolving solutions

• Overcoming the weaknesses of the system so as to achieve the organizational goals.

Objectives of System Analysis

To Find answers in the business process:

• What is being done?

• How is it being done?

• Who is doing it? When is he doing it?

• Why is it being done?

• How can it be improved • It is more of a thinking process and involves the

creative skills of the System Analyst.

Qualities of a System Analyst

1. The system analyst must be able to communicate in writing and orally.

2. The analyst must easily get along with people.

3. The analyst must be a good listener and be able to react to what people say.

Qualities of a System Analyst

4. The analyst must be knowledgeable of technology, a decent general knowledge of concepts and terms are essential.

5. The analyst must be knowledgeable of business. The analyst is not expected to be an expert in business but a decent understanding of the client's world is required.

Responsibilities of a System Analyst

•Developing cost analysis

•Design considerations

• Staff impact amelioration

• Implementation time-lines

Scientific Method of Solving Problem

1. Define a problem or opportunity in a systems context.

2. Gather data describing the problem or opportunity.

3. Identify alternative solutions.

4. Evaluate each alternative solution.

Scientific Method of Solving Problem

5. Select the best solution.

6. Implement the selected solution.

7. Evaluate the success of the implemented solution.