Foundation of IT - BIT CSIT BCA Exam 2083

Chapter 01

Introduction to IT

Information Technology भनेको data collect, store, process र communicate गर्न technology प्रयोग गर्ने विज्ञान हो।

IT को परिभाषा र महत्त्व

IT: Information Technology — hardware, software, network र data को combination
ICT: Information and Communication Technology — IT + Communication
Education, Business, Health, Government सबैमा IT को प्रयोग
Nepal मा IT sector तीव्र गतिमा बढ्दै छ

Computer को परिभाषा र विशेषताहरू

Speed: Millions of operations per second (MIPS)
Accuracy: GIGO — Garbage In Garbage Out
Storage: Large amount of data store गर्न सक्छ
Automation: Instructions follow गरेर automatic काम गर्छ
Versatility: विभिन्न किसिमका काम गर्न सक्छ
Diligence: थाक्दैन, लगातार काम गर्छ

Exam Important Computer को limitation: No Intelligence (आफैँ सोच्न सक्दैन), No Feeling, Dependent on Power।

Computer Generations

Generation	Period	Technology	Example
1st	1946–1955	Vacuum Tubes	ENIAC, UNIVAC
2nd	1956–1963	Transistors	IBM 7094
3rd	1964–1971	IC (Integrated Circuit)	IBM 360
4th	1972–present	Microprocessor (VLSI)	Intel, AMD
5th	Future	AI, ULSI, Quantum	AI Computers

याद गर्ने Trick Vacuum → Transistor → IC → Microprocessor → AI | "Very Tired IT Men Are"

Computer को Classification

Type	Based on	Examples
Analog	Continuous data	Thermometer, Speedometer
Digital	Discrete (0,1) data	PC, Laptop, Mobile
Hybrid	Both analog + digital	Hospital ECG machines

Size by	Type	Use
Supercomputer	Fastest, most powerful	Weather forecast, Research
Mainframe	Large, multi-user	Banks, Airlines
Minicomputer	Medium size	Mid-size businesses
Microcomputer	Personal use	PC, Laptop, Tablet

Chapter 02

Computer Hardware

Computer को physical components — Input, Output, Processing, Storage devices।

⚙️ Computer System Components

Computer Architecture

Input Device → CPU (ALU + CU + Registers) → Output Device
                    ↕
              Memory (RAM/ROM)
                    ↕
           Secondary Storage (HDD/SSD)

CPU — Central Processing Unit

ALU (Arithmetic Logic Unit): Mathematical र logical operations गर्छ
CU (Control Unit): सबै components लाई coordinate र control गर्छ
Registers: CPU भित्रको fastest temporary storage
Cache Memory: CPU र RAM बीचको fast buffer memory (L1, L2, L3)

Exam Important CPU = "Brain of Computer"। Clock speed GHz मा मापिन्छ। Cores: Dual core, Quad core, Octa core।

Input Devices

Device	Type	Use
Keyboard	Text input	Type गर्न
Mouse	Pointing device	Click, drag गर्न
Scanner	Image input	Document scan
Microphone	Audio input	Voice input
Webcam	Video input	Video capture
Touchscreen	Touch input	Tablet, phone
Barcode Reader	Code reader	Shopping, library
OMR	Mark reader	MCQ answer sheet
OCR	Text reader	Printed text read

Output Devices

Device	Type	Use
Monitor	Visual output	Display गर्न
Printer	Hard copy	Paper print
Speaker	Audio output	Sound निकाल्न
Projector	Visual output	Presentation
Plotter	Drawing output	Engineering drawings

Printer Types याद गर्नु Impact: Dot Matrix | Non-impact: Inkjet, Laser | Laser = fastest, best quality | Inkjet = color printing

Memory र Storage

Memory	Type	Speed	Volatile?
Register	CPU internal	Fastest	Yes
Cache (L1/L2)	CPU near	Very fast	Yes
RAM	Primary	Fast	Yes
ROM	Primary	Fast	No
HDD/SSD	Secondary	Slow	No
USB/CD/DVD	Tertiary	Slowest	No

Units याद गर्नु 1 KB = 1024 B | 1 MB = 1024 KB | 1 GB = 1024 MB | 1 TB = 1024 GB

Chapter 03

Software

Computer चलाउने instructions र programs — System Software र Application Software।

Software Classification

Type	Subcategory	Examples
System Software	Operating System	Windows, Linux, macOS
	Language Translator	Compiler, Interpreter, Assembler
	Utility Software	Antivirus, Disk Cleanup, WinZip
Application Software	General Purpose	MS Word, Excel, Photoshop
	Specific Purpose	Payroll, Inventory system
	Custom Software	Bank software, Hospital system

Language Translators

Translator	Converts	Execution
Compiler	High-level → Machine code (entire program)	Fast — सबै translate गरेर run
Interpreter	High-level → Machine code (line by line)	Slow — एक-एक line translate र run
Assembler	Assembly language → Machine code	Assembly programs को लागि

Compiler vs Interpreter Compiler: C, C++, Java | Interpreter: Python, JavaScript, PHP | Compiler faster, Interpreter debug गर्न सजिलो

Programming Languages Levels

Machine Language (1st gen): Binary (0,1) — fastest, hardware dependent
Assembly Language (2nd gen): Mnemonics (MOV, ADD) — Assembler चाहिन्छ
High-Level Language (3rd gen): English-like — C, Java, Python
4GL: Database languages — SQL, MATLAB
5GL: AI/Natural language — Prolog

Exam याद गर्नु Low-level = Machine dependent, Fast | High-level = Machine independent, Easy to program

Software Licensing Types

Proprietary/Commercial: किन्नुपर्छ — MS Office, Adobe
Freeware: Free तर source code नपाइने — VLC, Skype
Shareware: Trial period — WinRAR
Open Source: Free + source code पाइन्छ — Linux, Firefox, LibreOffice
Public Domain: कुनै restriction छैन

Chapter 04

Operating System

Hardware र User बीचको interface — सबैभन्दा important system software।

OS को Functions

Process Management: Programs को execution manage गर्छ
Memory Management: RAM allocate र deallocate गर्छ
File Management: Files र folders manage गर्छ
Device Management: Hardware devices control गर्छ
Security: User authentication र data protection
User Interface: CLI वा GUI provide गर्छ

Exam Important OS = "Soul of Computer" भनिन्छ। OS बिना computer चल्दैन।

Types of Operating Systems

Type	Feature	Example
Batch OS	Jobs queue मा process गर्छ	Early IBM systems
Time-Sharing	Multiple users simultaneously	UNIX
Real-Time (RTOS)	Immediate response	Medical devices, ATM
Distributed OS	Multiple computers एउटा OS	Google systems
Network OS	Network manage गर्छ	Windows Server
Mobile OS	Smartphones	Android, iOS

Popular Operating Systems

OS	Developer	Type
Windows 11	Microsoft	Proprietary, GUI
macOS	Apple	Proprietary, Unix-based
Linux (Ubuntu)	Community	Open Source, Free
Android	Google	Open Source, Mobile
iOS	Apple	Proprietary, Mobile

GUI vs CLI GUI (Graphical) = Windows, macOS — easy to use | CLI (Command Line) = Linux Terminal — powerful, faster

Process States र Scheduling

Process States

New → Ready → Running → Terminated
              ↑         ↓
           Waiting (I/O complete)

// CPU Scheduling Algorithms:
FCFS  - First Come First Serve
SJF   - Shortest Job First
Round Robin - Time quantum दिन्छ
Priority - High priority पहिले

Chapter 05

Computer Networking

Computers लाई एकआपसमा connect गरेर data share गर्ने technology।

Network Types

Type	Full Form	Coverage	Example
PAN	Personal Area Network	~10 meters	Bluetooth, USB
LAN	Local Area Network	Building/Campus	College network
MAN	Metropolitan Area Network	City	Cable TV
WAN	Wide Area Network	Country/World	Internet

याद गर्नु Internet = Largest WAN। Intranet = Private network (organization भित्र)। Extranet = Limited external access।

Network Topologies

Topology	Shape	Advantage	Disadvantage
Bus	Single cable	Simple, cheap	Single point failure
Star	Central hub/switch	Easy troubleshoot	Hub failure = all fail
Ring	Circle	Equal access	One failure = all fail
Mesh	Every-to-every	Most reliable	Expensive, complex
Tree	Hierarchical	Scalable	Root failure = problem

Most Common Star topology — office र school networks मा सबैभन्दा बढी प्रयोग हुन्छ।

Network Devices

Device	Layer	Function
Hub	Physical (L1)	Broadcast to all ports
Switch	Data Link (L2)	Send to specific MAC
Router	Network (L3)	Connect different networks
Bridge	Data Link (L2)	Connect 2 LANs
Gateway	All layers	Protocol conversion
Modem	Physical (L1)	Analog↔Digital convert
NIC	Data Link (L2)	Network interface card

OSI Model — 7 Layers

OSI Layers

7 - Application  - HTTP, FTP, SMTP, DNS
6 - Presentation - Encryption, Compression
5 - Session      - Session management
4 - Transport    - TCP/UDP, Port numbers
3 - Network      - IP address, Routing
2 - Data Link    - MAC address, Switch
1 - Physical     - Cables, Bits, Hub

// Trick: "All People Seem To Need Data Processing"

TCP/IP Model (4 layers) Application → Transport → Internet → Network Access | यो OSI भन्दा simplify हो।

Chapter 06

Internet & Web Technology

World को largest network र त्यसमा build भएका services।

Internet Services

Service	Protocol	Port	Use
WWW	HTTP/HTTPS	80/443	Web browsing
Email	SMTP/POP3/IMAP	25/110/143	Mail send/receive
FTP	FTP	21	File transfer
DNS	DNS	53	Name resolution
Telnet	Telnet	23	Remote access
SSH	SSH	22	Secure remote
VoIP	SIP/RTP	—	Voice calls

IP Address र DNS

IP Address

// IPv4 — 32 bit, 4 octets
192.168.1.1  ← format: X.X.X.X (0-255 each)

// IPv6 — 128 bit, hexadecimal
2001:0db8:85a3:0000:0000:8a2e:0370:7334

// Classes of IPv4:
Class A: 1-126.x.x.x    (Large networks)
Class B: 128-191.x.x.x  (Medium networks)
Class C: 192-223.x.x.x  (Small networks)

// DNS: www.google.com → 172.217.160.46

याद गर्नु 127.0.0.1 = Localhost (आफ्नै computer) | 192.168.x.x = Private IP

Web Technology

HTML: Structure — HyperText Markup Language
CSS: Style — Cascading Style Sheets
JavaScript: Behaviour — dynamic content
URL: Uniform Resource Locator — https://www.example.com/page
Domain: .com (commercial), .org (org), .edu (education), .np (Nepal)
Hosting: Website को files internet मा store गर्ने server

HTTP vs HTTPS HTTP = Not secure | HTTPS = SSL/TLS encrypted, secure | Green padlock = HTTPS

Email Architecture

Email flow

Sender → SMTP (send) → Mail Server
                              ↓
Receiver ← POP3/IMAP (receive) ←

// SMTP = Simple Mail Transfer Protocol (send)
// POP3 = Post Office Protocol (download & delete)
// IMAP = Internet Message Access Protocol (sync)

Chapter 07

Database

Organized collection of data जसलाई efficiently access, manage र update गर्न सकिन्छ।

Database Concepts

Database: Related data को organized collection
DBMS: Database Management System — Oracle, MySQL, MS Access
Table: Rows (records) र Columns (fields) को collection
Primary Key: Unique identifier — duplicate हुँदैन, NULL हुँदैन
Foreign Key: अर्को table को primary key reference गर्छ

DBMS Advantages Data redundancy कम | Data integrity | Data security | Easy data sharing | Backup & Recovery

Basic SQL Commands

SQL basics

-- Table बनाउने
CREATE TABLE Students (
    id INT PRIMARY KEY,
    name VARCHAR(50),
    marks FLOAT
);

-- Data हाल्ने
INSERT INTO Students VALUES(1, 'Ram', 85.5);

-- Data हेर्ने
SELECT * FROM Students;
SELECT name FROM Students WHERE marks > 80;

-- Data update गर्ने
UPDATE Students SET marks=90 WHERE id=1;

-- Data delete गर्ने
DELETE FROM Students WHERE id=1;

Database Models

Model	Structure	Example
Relational	Tables (rows & columns)	MySQL, Oracle, PostgreSQL
Hierarchical	Tree structure	IBM IMS
Network	Graph structure	IDS
Object-oriented	Objects	MongoDB (NoSQL)

Exam Tip Relational DBMS (RDBMS) सबैभन्दा popular। SQL = Structured Query Language।

Chapter 08

Cyber Security

Computer systems, networks र data लाई threats बाट protect गर्ने practice।

Malware Types

Malware	Description
Virus	Self-replicating, files मा attach हुन्छ, user action चाहिन्छ
Worm	Self-replicating, network बाट automatically spread हुन्छ
Trojan Horse	Legitimate software जस्तो देखिन्छ तर harmful
Spyware	User को activities secretly monitor गर्छ
Ransomware	Files encrypt गरेर ransom माग्छ
Adware	Unwanted advertisements देखाउँछ
Rootkit	OS level मा hide भएर system control गर्छ

Cyber Attacks

Phishing: Fake email/website बाट password चोर्ने
DoS/DDoS: Server लाई requests flood गरेर down गर्ने
Man-in-the-Middle: Communication बीचमा intercept गर्ने
SQL Injection: Database मा malicious SQL code inject गर्ने
Brute Force: सबै combinations try गरेर password crack
Social Engineering: लोग्याएर information निकाल्ने

Security Measures

Measure	Purpose
Firewall	Unauthorized network access block गर्छ
Antivirus	Malware detect र remove गर्छ
Encryption	Data लाई unreadable format मा convert गर्छ
VPN	Encrypted private tunnel बनाउँछ
2FA	Two-Factor Authentication — extra security layer
Backup	Data loss बाट protection
Digital Signature	Identity verify गर्छ

Encryption Types Symmetric: same key encrypt/decrypt (AES, DES) | Asymmetric: public/private key pair (RSA) | Hashing: one-way (MD5, SHA)

Chapter 09

Multimedia

Text, Image, Audio, Video र Animation को combination।

Multimedia Elements

Element	Formats	Use
Text	.txt, .doc, .pdf	Written content
Image	.jpg, .png, .gif, .bmp, .svg	Visual content
Audio	.mp3, .wav, .aac, .flac	Sound content
Video	.mp4, .avi, .mkv, .mov	Moving images
Animation	.gif, .swf, .css	Moving graphics

Image Types

Type	Description	Formats
Raster/Bitmap	Pixels बाट बनेको — zoom गर्दा blur	JPG, PNG, BMP, GIF
Vector	Mathematical paths — zoom गर्दा blur हुँदैन	SVG, AI, EPS

Image याद गर्नु JPEG = lossy compression (quality loss) | PNG = lossless, transparency support | GIF = animation support | SVG = scalable

Audio र Video Concepts

Sampling Rate: Audio quality — 44.1 kHz (CD quality)
Bit Rate: Data per second — higher = better quality, larger file
Resolution: Video quality — 720p, 1080p (Full HD), 4K
FPS: Frames Per Second — 24fps (cinema), 60fps (gaming)
Codec: Compress/decompress — H.264, H.265, MP3
Streaming: Real-time delivery — YouTube, Netflix

Multimedia Applications

Education: E-learning, Virtual classroom
Entertainment: Gaming, Movies, Music
Business: Presentations, Video conferencing
Healthcare: Medical imaging, Telemedicine
Virtual Reality (VR): Immersive 3D environment
Augmented Reality (AR): Real world + digital overlay

Chapter 10

E-Commerce, AI & Emerging Tech

Digital business, Artificial Intelligence र new technologies।

E-Commerce

Type	Full Form	Example
B2C	Business to Consumer	Daraz, Amazon
B2B	Business to Business	Alibaba, wholesalers
C2C	Consumer to Consumer	eBay, OLX
G2C	Government to Citizen	Online tax, e-passport

E-Commerce Advantages 24/7 available | Global reach | Low cost | Convenience | Easy comparison

Artificial Intelligence (AI)

AI: Machines लाई human-like intelligence दिने
Machine Learning (ML): Data बाट automatically learn गर्ने
Deep Learning: Neural networks बाट complex patterns learn
NLP: Natural Language Processing — human language understand
Computer Vision: Images/Videos बुझ्ने
Robotics: Physical tasks perform गर्ने machines

AI Applications ChatGPT (NLP) | Self-driving cars | Face recognition | Medical diagnosis | Recommendation systems

Cloud Computing

Service Model	Full Form	Example
IaaS	Infrastructure as a Service	AWS EC2, Azure VM
PaaS	Platform as a Service	Google App Engine, Heroku
SaaS	Software as a Service	Gmail, Office 365, Zoom

Cloud Deployment Public Cloud = Anyone use गर्न सक्छ (AWS, Google) | Private Cloud = Organization only | Hybrid = Both

Emerging Technologies

IoT (Internet of Things): Physical devices internet connected — Smart home, wearables
Blockchain: Decentralized, immutable ledger — Bitcoin, Ethereum
5G: 5th generation mobile network — faster, low latency
Big Data: Large volume, velocity, variety data — 3Vs
Quantum Computing: Quantum bits (qubits) — exponentially faster

Practice

Foundation of IT Quiz

आफ्नो तयारी जाँच गर्नुस् — BIT / CSIT / BCA exam questions जस्तै!

Foundation of IT — Exam

Introduction to IT

IT को परिभाषा र महत्त्व

Computer को परिभाषा र विशेषताहरू

Computer Generations

Computer को Classification

Computer Hardware

⚙️ Computer System Components

CPU — Central Processing Unit

Input Devices

Output Devices

Memory र Storage

Software

Software Classification

Language Translators

Programming Languages Levels

Software Licensing Types

Operating System

OS को Functions

Types of Operating Systems

Popular Operating Systems

Process States र Scheduling

Computer Networking

Network Types

Network Topologies

Network Devices

OSI Model — 7 Layers

Internet & Web Technology

Internet Services

IP Address र DNS

Web Technology

Email Architecture

Database

Database Concepts

Basic SQL Commands

Database Models

Cyber Security

Malware Types

Cyber Attacks

Security Measures

Multimedia

Multimedia Elements

Image Types

Audio र Video Concepts

Multimedia Applications

E-Commerce, AI & Emerging Tech

E-Commerce

Artificial Intelligence (AI)

Cloud Computing

Emerging Technologies

Foundation of IT Quiz