1. Introduction to Computers
1.1 What is a Computer?
A computer is an electronic machine that accepts raw data (input), processes it according to a set of instructions (program), and produces meaningful information (output). The term computer is derived from the Latin word computare, meaning “to calculate”.
Modern computers are not limited to calculations. They can store large amounts of data, communicate with other computers, control machines, assist in decision-making, and perform millions of tasks simultaneously.
1.2 Evolution of Computers
The development of computers has passed through several generations:
- First Generation (1940–1956): Vacuum tubes, very large size, high power consumption
- Second Generation (1956–1963): Transistors replaced vacuum tubes
- Third Generation (1964–1971): Integrated Circuits (ICs)
- Fourth Generation (1971–Present): Microprocessors
- Fifth Generation: Artificial Intelligence & Machine Learning
1.3 Characteristics of Computer
- Speed: Performs millions of operations per second
- Accuracy: Produces correct results if instructions are correct
- Diligence: Does not get tired or bored
- Storage: Stores huge amounts of data
- Automation: Works automatically once programmed
1.4 Limitations of Computer
- No intelligence of its own
- Cannot take decisions without instructions
- Depends entirely on user input
1.5 Applications of Computers
Computers are used in almost every field of life:
- Education – Online learning, exams, research
- Banking – ATM, online transactions
- Healthcare – Diagnosis, reports, patient records
- Government – Records, e-governance
- Entertainment – Movies, games, music
1.6 Computer System Components
A computer system consists of:
- Hardware
- Software
- Users
- Data
- Procedures
1.7 Summary
Computers have become an essential part of modern life. They help in increasing productivity, accuracy, and efficiency across all sectors.
2. Computer Hardware
2.1 Definition of Hardware
Hardware refers to the physical components of a computer system that can be seen and touched. Without hardware, software cannot function.
2.2 Input Devices
Input devices are used to enter data and instructions into the computer.
- Keyboard
- Mouse
- Scanner
- Microphone
- Webcam
2.3 Central Processing Unit (CPU)
CPU is the brain of the computer. It performs all processing tasks.
- Control Unit (CU): Directs operations
- Arithmetic Logic Unit (ALU): Performs calculations
- Registers: High-speed storage inside CPU
2.4 Memory
Memory stores data and instructions.
- Primary Memory: RAM, ROM
- Secondary Memory: Hard disk, SSD, Pen Drive
2.5 Output Devices
- Monitor
- Printer
- Speakers
- Projector
2.6 Storage Devices
Used to store data permanently.
- Hard Disk
- Solid State Drive (SSD)
- CD/DVD
- USB Flash Drive
2.7 Summary
Hardware components work together to perform computing tasks efficiently.
