Computer Science · Topic 01

Introduction to Computer Science

Discover what computer science studies, how computers process information, and how hardware, software, data, and algorithms work together.

1. What is Computer Science?

Computer science is the study of computation, information, algorithms, and the systems used to process information. It includes programming, data organisation, artificial intelligence, computer networks, security, and much more.

Example: A navigation app

It receives your location and destination, processes map data, calculates possible routes, and presents directions. Computer science helps explain how these steps can be designed efficiently.

2. What does a computer do?

A computer accepts input, processes it according to instructions, may store information, and produces output.

InputReceive data

ProcessingWork on data

StorageKeep data

OutputPresent results

These are functional stages, not always a strict sequence. A computer may store information before, during, or after processing, and some systems continuously receive input and produce output.

Example: Adding two numbers

Input: You enter 12 and 8.
Processing: The computer calculates 12 + 8.
Storage: The values or result may be held in memory.
Output: The screen displays 20.

3. Hardware and software

Hardware

The physical components of a computer that can be touched.

CPU
RAM and storage drives
Keyboard and mouse
Monitor and speakers

Software

Programs and instructions that tell hardware what tasks to perform.

Operating systems
Web browsers
Games and editors
Programming tools

Hardware and software depend on each other. A program provides instructions, while hardware executes those instructions.

Hardware	Typical role
CPU	Executes instructions and performs operations.
RAM	Temporarily holds data and instructions in use.
SSD or HDD	Stores files and programs persistently.
Input device	Supplies data or commands.
Output device	Presents information to a user or another system.

4. Data and information

Data consists of recorded values or observations. Information is data interpreted or organised so that it becomes meaningful in a particular context.

Data: 68, 72, 75, 85

Information: These are four test scores; their average is 75.

The distinction depends on context: information for one task may become raw data for another.

5. What is an algorithm?

An algorithm is a well-defined sequence of steps for solving a problem or completing a task. Algorithms can be written in ordinary language, pseudocode, flowcharts, or programming languages.

Example: Find the larger of two numbers

START
  INPUT A, B
  IF A > B
    DISPLAY A
  ELSE IF B > A
    DISPLAY B
  ELSE
    DISPLAY "Both numbers are equal"
END

A good algorithm should have clear instructions and produce the intended result for the inputs it is designed to handle.

6. Programming languages

Programming languages allow people to express instructions in a form that can be translated or executed by a computer system.

Language	Common uses
Python	Automation, data analysis, AI, education.
C	Systems programming and embedded software.
C++	Games, performance-intensive software, systems.
JavaScript	Interactive websites and web applications.
SQL	Querying and managing relational databases.

SQL is a specialised language for working with databases rather than a general-purpose programming language.

7. Major areas of Computer Science

Algorithms: Designing and analysing problem-solving methods.
Programming: Turning solutions into executable instructions.
Data structures: Organising data for effective use.
Computer architecture: Understanding how computer components work together.
Operating systems: Managing hardware and software resources.
Networks: Connecting devices to exchange data.
Cybersecurity: Protecting systems and information.
Artificial intelligence: Building systems that perform tasks associated with intelligent behaviour.

8. Quick knowledge check

Try answering each question before revealing the explanation.

Question 1: Which component executes program instructions?

The CPU executes program instructions. It works with memory and other components to carry out tasks.

Question 2: Is a web browser hardware or software?

Software. A web browser is a program used to access and interact with websites.

Question 3: What is an algorithm?

A well-defined sequence of steps designed to solve a problem or complete a task.

Question 4: What is the difference between RAM and persistent storage?

RAM temporarily holds data in use and is volatile; SSDs and HDDs retain stored data when power is off.

Key takeaways

Computer science studies computation, information, algorithms, and computing systems.
Hardware provides physical components; software provides instructions.
Computers process data to perform tasks and produce useful results.
Algorithms describe the steps used to solve problems.
Programming languages express instructions for computer systems.