Common beginner Computer IT Technology

Computer Literacy: Hardware, Software, Internet, and MS Office Basics

Essential computer knowledge for Kerala PSC — hardware components, software types, operating systems, internet basics, MS Office shortcuts, and common abbreviations. 3-5 questions per paper.

Published: 13 Apr 2026 Relevant for: LDC, Last Grade Servants, Graduate Level Prelims, Secretariat Assistant

Computer literacy questions appear in every Kerala PSC exam — typically 3-5 questions. They test basic knowledge, not programming. Memorise the facts below and you’ll get these marks easily.

Computer Generations

Generation	Period	Technology	Example
First	1940-1956	Vacuum tubes	ENIAC, UNIVAC
Second	1956-1963	Transistors	IBM 1401
Third	1964-1971	Integrated Circuits (IC)	IBM 360
Fourth	1971-present	Microprocessors (VLSI)	Personal computers, laptops
Fifth	Present-future	AI and parallel processing	Quantum computers, AI systems

PSC favourites:

First generation = Vacuum tubes
Second generation = Transistors
Third generation = Integrated Circuits (IC)
Fourth generation = Microprocessors
ENIAC = first general-purpose electronic computer (1946)

Hardware Components

Input Devices (send data TO the computer)

Keyboard, Mouse, Scanner, Microphone, Webcam, Joystick, Light Pen, Barcode Reader, Touchscreen, OCR (Optical Character Reader)

Output Devices (receive data FROM the computer)

Monitor, Printer, Speaker, Projector, Headphones, Plotter

Both Input and Output

Touchscreen, Modem, Network Card

Storage Devices

Type	Examples	Nature
Primary (volatile)	RAM	Loses data when power off
Primary (non-volatile)	ROM	Retains data when power off
Secondary	Hard Disk, SSD, USB Drive, CD, DVD	Permanent storage

Memory Hierarchy

Unit	Size
Bit	0 or 1 (smallest unit)
Nibble	4 bits
Byte	8 bits
Kilobyte (KB)	1,024 bytes
Megabyte (MB)	1,024 KB
Gigabyte (GB)	1,024 MB
Terabyte (TB)	1,024 GB

PSC trap: 1 KB = 1,024 bytes (not 1,000). This is because computers use binary (powers of 2): 2¹⁰ = 1,024.

CPU (Central Processing Unit)

The “brain” of the computer. Three main components:

Part	Function
ALU (Arithmetic Logic Unit)	Performs arithmetic and logical operations
CU (Control Unit)	Controls and coordinates all computer operations
Registers	Small, fast temporary storage inside CPU

Software

Types of Software

Type	Description	Examples
System Software	Manages hardware and provides platform for applications	Windows, Linux, macOS, Android
Application Software	Programs for specific tasks	MS Word, Excel, Chrome, Tally
Utility Software	System maintenance tools	Antivirus, Disk Defragmenter, WinZip

Operating Systems (OS)

OS	Developer	Key fact
Windows	Microsoft	Most widely used desktop OS
macOS	Apple	For Mac computers only
Linux	Linus Torvalds (1991)	Open source; free
Android	Google (originally Andy Rubin)	Most popular mobile OS
iOS	Apple	For iPhones and iPads
Ubuntu	Canonical	Popular Linux distribution; used in Kerala government

PSC facts:

Linux creator: Linus Torvalds (1991)
Android is based on: Linux kernel
Kerala government uses: Linux/Ubuntu in many offices
MS-DOS was Microsoft’s first OS (Disk Operating System)
BOSS (Bharat Operating System Solutions) = Indian Linux distribution

Number Systems

System	Base	Digits used
Binary	2	0, 1
Octal	8	0-7
Decimal	10	0-9
Hexadecimal	16	0-9, A-F

Basic conversions (PSC level):

Binary of 5 = 101
Binary of 10 = 1010
Computers use binary (0 and 1) internally

Internet Basics

Key Terms

Term	Full form / Meaning
WWW	World Wide Web
URL	Uniform Resource Locator
HTTP	HyperText Transfer Protocol
HTTPS	HTTP Secure (encrypted)
HTML	HyperText Markup Language
IP Address	Internet Protocol Address (unique computer address)
DNS	Domain Name System (converts domain names to IP addresses)
ISP	Internet Service Provider
Wi-Fi	Wireless Fidelity
LAN	Local Area Network
WAN	Wide Area Network
MAN	Metropolitan Area Network
VPN	Virtual Private Network
Firewall	Security system that monitors network traffic
Browser	Software to access websites (Chrome, Firefox, Edge)
Search Engine	Tool to search the internet (Google, Bing, Yahoo)

Internet History

Fact	Detail
ARPANET	Predecessor of the internet (1969, US Department of Defence)
WWW invented by	Tim Berners-Lee (1989, at CERN)
First website	info.cern.ch (1991)
Email invented by	Ray Tomlinson (1971); introduced @ symbol
Google founded	1998 (Larry Page and Sergey Brin)
Facebook founded	2004 (Mark Zuckerberg)
Twitter founded	2006 (Jack Dorsey)
Internet in India	VSNL launched public internet on 15 August 1995

Most asked internet questions:

WWW inventor: Tim Berners-Lee
Email inventor: Ray Tomlinson (@ symbol)
ARPANET = predecessor of internet
Internet in India: 15 August 1995 (by VSNL)
Google founders: Larry Page and Sergey Brin

MS Office Basics

MS Word Shortcuts

Shortcut	Action
Ctrl + C	Copy
Ctrl + V	Paste
Ctrl + X	Cut
Ctrl + Z	Undo
Ctrl + Y	Redo
Ctrl + A	Select All
Ctrl + S	Save
Ctrl + P	Print
Ctrl + B	Bold
Ctrl + I	Italic
Ctrl + U	Underline
Ctrl + F	Find
Ctrl + H	Find and Replace
Ctrl + N	New document
Ctrl + O	Open file
F7	Spell check

MS Excel Basics

Fact	Detail
File extension	.xlsx (or .xls for older)
Cell address	Column letter + Row number (e.g., A1, B3)
Rows	1,048,576 (numbered)
Columns	16,384 (A to XFD)
Formula starts with	= (equals sign)
SUM function	=SUM(A1:A10)
AVERAGE function	=AVERAGE(A1:A10)
MAX function	=MAX(A1:A10)
MIN function	=MIN(A1:A10)
COUNT function	=COUNT(A1:A10)

MS PowerPoint

Fact	Detail
File extension	.pptx
Purpose	Presentations/slideshows
New slide	Ctrl + M
Start slideshow	F5
Start from current slide	Shift + F5

File Extensions

Extension	Software/Type
.docx	MS Word
.xlsx	MS Excel
.pptx	MS PowerPoint
.pdf	Adobe PDF
.jpg/.png	Image files
.mp3	Audio file
.mp4	Video file
.html	Web page
.txt	Plain text
.zip	Compressed file

Important Abbreviations

Abbreviation	Full Form
CPU	Central Processing Unit
RAM	Random Access Memory
ROM	Read Only Memory
ALU	Arithmetic Logic Unit
USB	Universal Serial Bus
LED	Light Emitting Diode
LCD	Liquid Crystal Display
GPS	Global Positioning System
PDF	Portable Document Format
JPEG	Joint Photographic Experts Group
GIF	Graphics Interchange Format
ASCII	American Standard Code for Information Interchange
BIOS	Basic Input Output System
SIM	Subscriber Identity Module
ATM	Automated Teller Machine
PIN	Personal Identification Number
UPI	Unified Payments Interface
QR Code	Quick Response Code

Computer Virus and Security

Term	Meaning
Virus	Malicious program that attaches to files and spreads
Worm	Self-replicating program that spreads through networks
Trojan Horse	Malicious program disguised as legitimate software
Malware	General term for malicious software
Phishing	Fraud where attackers impersonate trusted entities to steal data
Antivirus	Software that detects and removes viruses (Norton, Kaspersky, Avast)
Spam	Unwanted bulk emails
Hacking	Unauthorized access to computer systems
Encryption	Converting data into code for security

Quick Revision — 20 Most Asked Computer Questions

Full form of CPU: Central Processing Unit
Brain of computer: CPU
1 KB = 1,024 bytes
Smallest unit of data: Bit
1 byte = 8 bits
RAM is: Volatile (loses data when power off)
ROM is: Non-volatile (retains data)
First generation used: Vacuum tubes
WWW inventor: Tim Berners-Lee
Email inventor: Ray Tomlinson
Linux creator: Linus Torvalds
Google founders: Larry Page & Sergey Brin
Ctrl + C: Copy
Ctrl + V: Paste
Ctrl + Z: Undo
Excel formula starts with: = (equals)
Binary uses digits: 0 and 1
Internet in India: 15 August 1995
Full form of HTML: HyperText Markup Language
Full form of Wi-Fi: Wireless Fidelity

Notes compiled from Kerala PSC computer literacy questions (2015-2024). Covers all question types appearing in LDC, Graduate Level, and Secretariat Assistant papers.

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