GK · Chapter 16

Computer

Fundamentals · Hardware · Software · Networks · AI · Robotics

Introduction

Father of Computer: Charles Babbage
Father of Modern Computer: Alan Turing
First calculating device: Abacus
First general-purpose programmable electronic digital computer: ENIAC

Generations of Computers

Generation	Period	Technology
First	1940–56	Vacuum Tube
Second	1956–63	Transistor (Semiconductor)
Third	1964–71	Integrated Circuit (Silicon)
Fourth	1971–Present	Microprocessor and VLSI
Fifth	Present–Future	ULSI, parallel processing and AI

⚡ QUICK RECALL The third generation of computers began with the IBM 360 — a key marker question in exams.

Classification of Computers

By Size	By Function
Micro Computer	Analog Computer
Mini Computer	Digital Computer
Mainframe Computer	Hybrid Computer
Super Computer	—

Supercomputers

Rank	Indian Supercomputers — dated records
1	Dell PowerEdge XE9680 system at Shakti Cloud, Yotta Data Services — global rank 32
Historical	AIRAWAT: ranked 75th globally in May 2023
Weather HPC	Pratyush (IITM, Pune), inaugurated January 2018

Rank	Top World Supercomputers — June 2026 snapshot
1	LineShine — National Supercomputing Centre in Shenzhen, China
2	El Capitan — USA
3	Frontier — USA
4	Aurora — USA

⚡ QUICK RECALL On 26 September 2024, PM Narendra Modi launched three PARAM Rudra supercomputers and inaugurated two HPC systems — ArKa and Arunika — for weather and climate research.

Components of a Computer

Input Unit, Output Unit, Central Processing Unit (CPU), Memory Unit

Input Unit	Output Unit
Keyboard, Mouse, Scanner	Printer, Monitor (touchscreen: both input and output)
Microphone, OCR	Plotters, Speaker
Trackball, Light Pen, MICR	Projector

CPU is the "Brain of the Computer" — comprises Control Unit (CU), Arithmetic Logic Unit (ALU), and registers.

Primary & Secondary Storage

Storage Type	Details
RAM	Random Access Memory — Temporary, Volatile, Dynamic/Static memory
ROM	Read Only Memory — Permanent, Non-Volatile; types: PROM, EEPROM, EPROM
Secondary Storage	External/auxiliary/backup memory; stores data permanently

Magnetic Storage: Hard Disk Drive, Floppy Disk, Magnetic Tape
Optical Storage: CD-R, DVD, Blu-ray Disc
Solid State Storage: Pen Drive, Memory Card

Memory Units

Unit	Equivalent
1 Bit	Binary digit (0 or 1)
8 Bits	1 Byte = 2 Nibbles
1024 Bytes	1 KiB
1024 Kilobytes	1 MiB
1024 Megabytes	1 GiB
1024 Gigabytes	1 TiB
1024 Terabytes	1 PiB
1024 Petabytes	1 EiB

Important Hardware Facts

Term	Description
Motherboard	Main/base/system/logic board; central PCB connecting all components
DMA	Direct Memory Access; hardware transfers data to/from memory bypassing CPU
Cache Memory	Fast memory between CPU and main memory; improves data retrieval speed
Burning	Writing data to a CD/DVD using a laser
MAR	Memory Address Register; holds address of memory location to be accessed

System Software & Operating Systems

System Software: collection of programs; handles execution of all tasks
Single-user OS: MS-DOS and Windows 9x
Device drivers: group of directions
Booting: starting or restarting a computer
Window Task Manager: utility application of MS Windows
Standby: power management feature of Windows

Types of Operating Systems
Batch Operating System
Time-Sharing Operating System
Distributed Operating System
Network Operating System
Multi-Tasking Operating System
Multi-Processing Operating System

Utility, Application & Open Source Software

Utility Software	Function
Disk Compression	Reduces file/folder size on storage
Disk Cleaners	Deletes temporary/junk files
Disk Defragmenter	Rearranges fragmented files
Text Editor	Creating/editing text files (e.g., Notepad)
Anti-Virus	Avira, Kaspersky, AVG, etc. — removes viruses

Application Software: word processing, presentation, reservation systems, payroll, office management, etc.
Open Source Software: Linux, Firefox, LibreOffice, Chromium (Chrome and Opera are proprietary browsers) — source code freely available to anyone
Shortcut for renaming files/folders in Windows: F2
DBMS: manages comprehensive data collection and query execution
Spreadsheet Software: used for financial statements

Programming Languages

Low-Level: Machine Language (0s & 1s), Assembly Language
Medium-Level: bridge between low and high-level languages
High-Level: uses English words and mathematical symbols

Language	Application
FORTRAN	Mathematical applications
ALGOL	Scientific applications
LISP	Artificial intelligence
COBOL	Business applications
BASIC / PASCAL	Teaching programming
C	System programming
C++	System object programming
JAVA	Internet-based programming

Translator	Function
Assembler	Translates assembly code to machine code
Compiler	Translates entire high-level code to machine code before execution
Interpreter	Executes high-level code line by line

Microsoft Office Suite

Application	Key Facts
MS Word	Word processing; File format: .doc/.docx; Default font: Aptos (replaced Calibri in early 2024)
MS Excel	Spreadsheet program; File format: .xls/.xlsx; default column width: 8.43 characters
MS PowerPoint	Presentation software; File format: .ppt/.pptx
MS Access	DBMS; File format: .accdb (.mdb prior to Access 2007)

Key Shortcut	Function
F1	Open Help window
F5 (Word)	Go To dialog (page, section, line, etc.)
F5 (PowerPoint)	Start slide show from beginning
Shift+F5	Start slide show from current slide
F12	Open Save As window
Ctrl+M	Insert new slide (PowerPoint)
Ctrl+U	Underline cell content (Excel)
Ctrl+D	Font dialog box (Word) / Fill Down (Excel)
Ctrl+A	Select all items
Ctrl+C / Ctrl+V	Copy / Paste
Ctrl+P	Print document
Ctrl+B	Bold selected text
Ctrl+K	Insert hyperlink
Ctrl+L	Align text left

⚠ EXAM TRAP F5 does DIFFERENT things in Word (opens Go To) vs PowerPoint (starts slide show) — the same key, different function per application.

Computer Networks

Type	Coverage	Speed	Location
LAN	Local area	No fixed speed specified by network category	A limited local area such as a home, office, school, building or campus
MAN	City/metropolitan area	No fixed speed specified by network category	A metropolitan/city-scale network connecting multiple LANs
WAN	Countries/continents	No fixed speed specified by network category	A large geographic area connecting networks across regions, countries or continents

HDLC is a data-link protocol used on particular links; it does not define every WAN.
Network Devices: Repeater, Gateway, Switch, Router, Modem, Hub
VPN: creates an encrypted tunnel between endpoints; it does not guarantee complete anonymity
Network Topology: Ring, Bus, Tree, Star, Mesh
ISDN: digital/standard telephone service
Cloud Computing: on-demand access to shared computing resources and services over a network

Internet

Internet: network of networks connecting computers worldwide
Connections: Dial-up; Broadband (cable modem, fiber optic, DSL); Wireless (Wi-Fi, Wi-MAX, satellite)
World Wide Web (WWW): created by Tim Berners-Lee in 1989
Web Page: documents written in HTML
Web Address: URL — indicates internet address of files
Domain Name: identifies a website (e.g., www.example.com)
Search Engines: Google, Bing, Yahoo and DuckDuckGo

Protocol	Purpose
TCP	Transmission Control Protocol
IP	Internet Protocol
FTP	File Transfer Protocol
HTTP	Hypertext Transfer Protocol
SMTP	Simple Mail Transfer Protocol

Internet Services: Chatting, Video Conferencing, Social Networking, E-commerce, Blogging, E-mail
Gmail: direct attachments up to 25 MB; larger files use Google Drive links; sorts emails by date by default; searchable by From, To, Subject, Date

Mobile Communication Generations

Gen	Year/Country	Technology	Key Feature
1G	Japan, 1979	Analog cellular	Analog radio signal
2G	Finland, 1991	Digital networks	Digital radio signal
3G	Japan, 2001	High-speed IP data	High-speed IP data
4G	Norway & Sweden, 2009	Increased mobile broadband	Higher communication speeds
5G	South Korea, 2019	High-frequency speeds	Download speeds up to 20 Gbps

Telecom Regulatory Authority of India: TRAI

Artificial Intelligence

Dartmouth workshop, 1956; John McCarthy coined the term artificial intelligence
Definition: ability of machines to simulate human cognitive functions
Related field: Natural Language Processing (NLP)

AI Tool	Launch Year	Company
DeepSeek (AI Chatbot)	2025	DeepSeek
Qwen 3	2025	Alibaba
Grok 4	2025	xAI
Gemini	2023	Google DeepMind
ChatGPT	2022	OpenAI

Computer Security

Threat	Description
Malware	Malicious software
Viruses	Malware that attaches to a host file/program and replicates when the infected host executes
Worms	It self-replicates and can spread automatically across systems/networks without attaching to a host file
Ransomware	Malicious software demanding ransom
Trojan Horse	Non-self-replicating malware
Spyware	Secretly monitors activity
Hacking / Cracking	Unauthorized system access
Phishing	A social-engineering attack that tricks people into revealing credentials or other sensitive information
Firewall	Filters network traffic and control

Anti-Virus Software: Norton, McAfee, Kaspersky, Avast, AVG
MPEG: Moving Picture Experts Group — compression format
Hibernate: power management feature
Consumer Skype was retired on 5 May 2025
Two-Factor Authentication: uses two different factor types, such as password plus OTP or biometric

Important Robots

Robot	Key Details
Rex	A humanoid demonstration built from advanced bionic prostheses and synthetic organs
Kirobo	First talking robot in space
Snake Robot	Assists in accidents (DRDO)
FemiSapien	Intelligent robot
Sophia	Communicates with humans (Saudi Arabia)
Daksha / Netra	Daksh is a remotely operated bomb-disposal UGV; Netra is a lightweight surveillance/reconnaissance UAV developed with ideaForge
Vyommitra	Half-humanoid for Gaganyaan Mission, by ISRO
FEDOR	Russian humanoid robot
Zhurong	China's Mars rover, part of Tianwen-1 mission
Mitra	An Indian-designed service humanoid by Invento Robotics for customer interaction and hospitality-type tasks
Pioneer	Radiation-hardened remote structural assessment and monitoring inside the Unit-4 shelter

⚠ EXAM TRAP Tianwen-1 is the MISSION name; Zhurong is the ROVER that landed as part of that mission — don't treat them as the same entity.

Quick Reference Summary

Father of ComputerCharles Babbage

Father of Modern ComputerAlan Turing

First Digital ComputerENIAC: first general-purpose programmable electronic digital computer

First Calculating DeviceAbacus

Top Indian SupercomputerDell PowerEdge XE9680 system at Shakti Cloud, Yotta Data Services — global rank 32

Top World SupercomputerLineShine — National Supercomputing Centre in Shenzhen, China

RAMTemporary / Volatile memory

ROMPermanent / Non-Volatile memory

CPUBrain of computer; Control Unit, ALU and registers

WWW CreatorTim Berners-Lee (1989)

1G TechnologyJapan, 1979; Analog

2G TechnologyFinland, 1991; Digital

5G TechnologySouth Korea, 2019; Download 20 Gbps

AI FounderJohn McCarthy coined the term; Dartmouth workshop, 1956

ChatGPTLaunched 2022; OpenAI

DeepSeekLaunched 2025; DeepSeek

MS Word Default FontAptos (replaced Calibri, early 2024)

DBMS File Format.accdb (.mdb prior to Access 2007)

India's First Humanoid RobotMitra: service humanoid developed by Invento Robotics; avoid an unqualified first claim

VyommitraHalf-humanoid by ISRO for Gaganyaan Mission

TRAITelecom Regulatory Authority of India

FirewallFilters network traffic and control