CIT 303: System Analysis and Design

By

Olatunji, E.K.

Computer Sc ProgrammeCOCCS

Bowen University, Iwo

November 2020

Course Contents

Part I:

• System Concept.

• A revision of system development life cycle

• System analysis fundamentals, info requirements analysis

• Analysis Process: fact gathering techniques, data flow diagrams, process description,, data modelling

Part II -

Part III -

Course Outline

• Important Terms in System Analysis & Design (SAD)

• Distinct Stages in System Development

• System Development life Cycle (SDLC) Models / Methodology

Recommended Ref Materials

• Introductory Data Processing by Olatunji, E.K.

• Computer Science by C.S French

• Overview of System Analysis & Design(SAD) by D. Kumar

• SAD Lecture notes by J. T. Ogbiti

• SAD by Dennis, Wiscom & Tegandem

• Many Online Resources

• Ref Materials from Co-Lecturers on the same Course

SECTION I:Description of some Basic terms in System Analysis (S/A)• What is a system? – 2 main definitions

• 1a. The word System is derived from Greek word Systema, which means an organized relationship between any set of components to achieve some common cause or objective (Tutorialspoint.com ).

• b. A set of things or components working together to carry out a well-defined function or accomplish a common goal.

• Examples

• In physiology or biology; it is a set of organs in the body with a common structure or function.; A biological system is a group of organs that work together to carry out a particular task. In humans, there are different biological systems; such as digestive system, reproductive system, nervous system, etc

• In Computing, a group of related hardware units or programs or both, especially when dedicated to a single application.

What is a system ?

• 2. what is a system ?

• a collection of procedures for solving a problem or accomplishing a specific but well defined task. Examples are :• Procedure or system of registering students in a college (student registration system)• Registration procedure for a newly bpought motor vehicles (Vehicle registration system)• Procedure or system of computing overall result of a student on graduation (Examination

Result system)• System or procedure of calculating of calculating the salary of employees of an organization,

etc (Payroll system)

• Note:

• Examination processing system can refer to:

• Either – the procedure of doing / processing exam result

• Or – the computer application software doing / carrying out the procedure

What is a system? Contd

• Characteristics of a System

• Our definition of a system suggests some characteristics that are present in all systems: organization (order), interaction, interdependence, integration and a central objective.

• 1 Organization

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

• 2 Interaction

• Interaction refers to the manner in which each component functions with other components of the system.

• In a computer system, the central processing unit must interact with the input device to solve a problem. In turn, the main memory holds programs and data that the arithmetic unit uses for computation.

What is a system ? Contd

• Characteristics of a System Contd

• 3. Interdependence

• Interdependence means that parts of the organization or computer system depend on one another. They are coordinated and linked together according to a plan. One subsystem depends on the input of another subsystem for proper functioning: that is,

the output of one subsystem is the required input for another subsystem.This interdependence is crucial in systems work

• Interdependence is further illustrated by the activities and support of systems analysts, programmers, and the operations staff in a computer centre.

• A decision to computerize an application is initiated by the user, analyzed and designed by the analyst, programmed and tested by the programmer, and run by the computer operator

Characteristics of a System Contd

• 4. Integration

• Integration refers to the holism of systems. Synthesis follows analysis to achieve the central objective of the organization. Integration is concerned with how a system is tied together.

• 5. Central objective

• The last characteristic of a system is its central objective. Objectives may be real or stated.

• users must know the central objective of a computer application early in analysis for a successful design and conversion.

•

Information System (IS)

• What is an info system?

• It is a computer system or set of components for collecting, creating, storing, processing, and distributing information, • typically including hardware and software, system users, and the data itself:• The use of information systems is to solve business problems.

• The purpose of an information system is to turn raw data into useful information that can be used for decision making in an organization. • Many information systems are designed to support a particular process within an

organization or to carry out very specific analysis

• NB: System in this course refers to computer software application or Computer information system

System Analysis

• What is system analysis?

• It is the process of collecting and interpreting facts/data about a system / procedure (manual or computerized) with the purpose of: • Understanding

The functions/& obj of the sytem

Different components of the system and their functions

Strength, weakness/problems of the system

To see whether the system is meeting the obj of the org for which is developed

• Finding means and ways of accomplishing the system’s goal and obj more effectively and efficiently.

•

System Design

• What is system design?• Systems design is the process of defining elements of a system like

modules, architecture, components and their interfaces and data for a system based on the specified requirements.

• It is the process of defining, developing and designing systems which satisfies the specific needs and requirements of a business or organization.

• Or• The process of defining the elements/components of a system and the

interrelationships among the components to satisfy the functional requirements of the system

• For computer application system, it is the process of defining the elements/components of the system (such as program modules, databases/file, user interfaces, etc)

System Design Contd

• The designs can be defined in graphical or textual modelling languages.

Some of the examples of graphical modelling languages are

• a. Unified Modelling Language (UML): To describe software both structurally and behaviourally with graphical notation.

b. Flowchart : A schematic or stepwise representation of an algorithm.

c. System flowcharts

•

System Design Contd

• Design methods:

1) Architectural design: To describes the views, models, behaviour, and structure of the system.

2) Logical design: To represent the data flow, inputs and outputs of the system. Example: ER Diagrams (Entity Relationship Diagrams).

3) Physical design: Defined as a) How users add information to the system and how the system represents information back to the user. b) How the data is modelled and stored within the system. c) How data moves through the system, how data is validated, secured and/or transformed as it flows through and out of the system.

•

A System Analyst (S/At)

• Who is a System Analyst (S/At)?

• Computer systems analysts take a look at a company's current computer systems and procedures, and then find a way to have them operate in a more efficient and effective way. • They provide technology design solutions by understanding business needs and information

technology.

• Computer Systems Analysts work to ensure that all computer systems within an organization serve to support organizational goals. • They are tasked with collaborating with colleagues to determine the strengths and weaknesses of

the existing systems and identifying areas for improvement. • They then take this information and design and build improved systems. • Computer Systems Analysts work across a multitude of industries and generally form part of an

engineering or IT team.

• They are responsible for the analysis, design, and implementation of computer systems.

•

A System Analyst (S/At)

Required Skills for a S/At

• A System Analyst should also possess the following skills:

• Critical thinking ability

• Strong problem-solving capacity

• High-level written and verbal communication skills

• Project management skills

• Ability to work under pressure and to tight deadlines

• Knowledge of data modelling and data visualisation tools

System Development Life Cycle (SDLC)

• system development life cycle (SDLC)

• The system development life cycle is a project management model that defines the stages involved in bringing a project from inception to completion.

• (SDLC) is a conceptual model used in project management that describes the stages involved in an information system developmentproject, from an initial feasibility study through maintenance of the completed application. (preferred !)

CIT 303 First Assignment 1 2020-2021

1. Write on the contents of a system proposal

2. Discuss briefly on the data collection/fact finding techniques

3. A school of thought groups phases of SDLC into four.

a) What are these steps

b) Write on the activities performed in each of the four phases

4. Waterfall is one of the system development models/methodologies

a) Describe what this model entail

b)Describe 5 other models of system development

5. Feasibility study is an important stage in system analysis.

a) What is feasibility study?

b) What is the importance of feasibility study?

c) Briefly discuss the various steps in feasibility study

d) Write briefly on the contents of feasibility study report

•

• Due date: 3rd December 2020