Introduction to Computers – 

📌 Introduction to Computers

A computer is an electronic machine that receives data (input), processes it, and gives meaningful information (output).
It works very fast, stores a large amount of data, and performs multiple tasks easily.
Computers are used in education, banking, offices, hospitals, shops, and almost every sector today.

Computer = Input + Processing + Output + Storage

1️⃣ What is a Computer?

A computer is a programmable electronic device that can perform arithmetic and logical operations automatically.

Key Functions of a Computer

• Input (data देने की प्रक्रिया)

• Processing (data को process करना)

• Output (result प्रदान करना)

• Storage (data save करके रखना)

2️⃣ Characteristics of Computers (विशेषताएँ)

Computers are popular because of these qualities:

✔ Speed – लाखों calculations एक सेकंड में

✔ Accuracy – results always correct

✔ Storage – huge data save कर सकते हैं

✔ Automation – बिना रुकावट काम

✔ Diligence – थकान नहीं होती

✔ Multitasking – कई काम एक साथ

3️⃣ Types of Computers

Computers are divided based on size, power & purpose.

### (A) Based on Size

1. Super Computer – सबसे तेज़, scientific research

2. Mainframe Computer – बड़ी कंपनियाँ, banks

3. Mini Computer – small servers

4. Micro Computer – PC, laptop (जनता के लिए)

(B) Based on Purpose

1. General Purpose Computer → MS Office, internet

2. Special Purpose Computer → ATM, vending machines

(C) Based on Data Handling

1. Analog Computer

2. Digital Computer

3. Hybrid Computer

4️⃣ Basic Computer Block Diagram

Input ➝ Processing (CPU) ➝ Output
⬑ Storage

5️⃣ Computer Components

The computer system is divided into 2 parts:

(A) Hardware

Physical parts you can touch:

• Keyboard

• Mouse

• Monitor

• CPU

• Printer

• Hard Disk

• Pen Drive

(B) Software

Programs that run on the computer:

• Operating System (Windows, Linux)

• MS Office

• Browser (Chrome)

• Tally

• VLC Player

6️⃣ Input and Output Devices

Input Devices

• Keyboard

• Mouse

• Scanner

• Microphone

• Barcode Reader

• Touch Screen

• Webcam

Output Devices

• Monitor

• Printer

• Speaker

• Projector

7️⃣ Central Processing Unit (CPU)

CPU is the brain of the computer.

CPU Parts:

1. ALU – Arithmetic & Logical operations

2. CU – Controls all activities

3. Memory Unit – Data storing

8️⃣ Memory in Computer

Memory = data temporarily or permanently store करना

(A) Primary Memory

• RAM (temporary)

• ROM (permanent instructions)

(B) Secondary Memory

• Hard Disk

• SSD

• Pen Drive

• Memory Card

9️⃣ Software

Software दो प्रकार का होता है:

System Software

• Operating System (Windows, Linux)

• Device Drivers

Application Software

• MS Office

• Browser

• Tally

• Photoshop

🔟 Operating System (OS)

Operating System वह software है जो user और computer के बीच connection बनाता है।

Functions of OS

• File management

• Memory management

• Device control

• User interface

• Security

Examples: Windows, Linux, macOS, Android

1️⃣1️⃣ Computer Applications (Uses of Computers)

Computers are used in:

• Education

• Banking

• Business

• Railway & Airline Reservation

• Hospital

• E-Commerce

• Digital Payments

• Gaming

• Graphic Designing

1️⃣2️⃣ Computer Virus & Security

Virus = unwanted program
It can:

• Delete files

• Slow down computer

• Steal data

Protection:

• Antivirus use करें

• Unknown files download न करें

• Strong passwords रखें

• Regular updates करें

1️⃣3️⃣ Advantages & Disadvantages

Advantages

✔ Fast
✔ Accurate
✔ Multitasking
✔ Reliable
✔ Storage capacity high

Disadvantages

✘ No IQ
✘ Dependence
✘ Electricity requirement
✘ Cyber risks

📘 Computer Generations –

कंप्यूटर का विकास पाँच पीढ़ियों (Five Generations) में हुआ है।
हर generation में नई technology, छोटे size, तेज speed और कम power consumption वाले कंप्यूटर बने।

1️⃣ First Generation 

साल: 1940 – 1956
Technology: Vacuum Tubes
Language: Machine Language (0 और 1)

Features

• बहुत बड़े (Room-size)

• भारी Heat generate करते थे

• बहुत ज्यादा बिजली खर्च

• Speed बहुत कम

• Memory बहुत कम

Examples

• ENIAC

• EDVAC

• UNIVAC-1

Uses

Scientific calculations, military research

2️⃣ Second Generation 

साल: 1956 – 1963
Technology: Transistors (Vacuum tube का छोटा, fast version)
Language: Assembly Language

Features

• Size छोटा

• Speed तेज

• Heat कम

• Reliability बढ़ी

• Maintenance कम

Examples

• IBM 1401

• IBM 7094

Uses

Business applications, accounting, payroll processing

3️⃣ Third Generation 

साल: 1964 – 1971
Technology: IC (Integrated Circuit)
Language: High-Level Languages (C, FORTRAN, COBOL)

Features

• बहुत छोटा size

• Cost कम

• Efficiency और speed ज्यादा

• Commercially successful computers

Examples

• IBM 360 series

• Honeywell 6000

Uses

Education, scientific, commercial applications

4️⃣ Fourth Generation (चौथी पीढ़ी)

साल: 1971 – Present
Technology: Microprocessor (Single chip CPU)

Features

• Personal Computer (PC) का जन्म

• Laptop, Desktop, Tablet

• Speed बहुत high

• Storage बहुत ज्यादा

• Size smallest

• Low cost

• GUI Operating System जैसे Windows

Examples

• Intel 4004 (first microprocessor)

• IBM PCs

• Apple Macintosh

Uses

Almost every field – घर, ऑफिस, स्कूल, बैंक, बिज़नेस, इंटरनेट, AI

5️⃣ Fifth Generation (पाँचवीं पीढ़ी) – Present & Future

Technology: Artificial Intelligence (AI), Machine Learning (ML), Robotics, Quantum Computing

Features

• Self-learning computers

• Superfast processing

• Natural language processing

• High-level robotics

• Cloud computing

• IoT (Internet of Things)

Examples

• AI-based systems

• Google Assistant, Siri

• Quantum Computers (in development)

Uses

Automation, driverless cars, virtual assistants, advanced robotics, smart devices

📌 Generation Comparison Table (Summary)