Fundamental of IT homework

DATA: Raw facts and figures
Example: 25, 19, 31, 28, 22 (temperature readings)

INFORMATION: Processed, meaningful data
Example: "Average temperature is 25°C"
         "Temperature increased 5°C from morning"

KNOWLEDGE: Patterns and relationships in information
Example: "Higher temperatures occur in summer months"

INPUT DEVICES:
- Keyboard, Mouse, Scanner
- Tactile screen, Microphone
- Sensor devices

PROCESSING UNIT:
- CPU (Central Processing Unit)
- RAM (Random Access Memory) - temporary
- This is the "brain" of computer

STORAGE DEVICES:
- Hard Disk Drive (HDD)
- Solid State Drive (SSD)
- USB Flash drives
- SD Cards

OUTPUT DEVICES:
- Monitor/Screen
- Printer
- Speaker
- Projector

APPLICATION SOFTWARE (User-facing)
- Microsoft Word, Excel, PowerPoint
- Google Docs, Sheets, Slides
- Photoshop, Illustrator

OPERATING SYSTEM (Middle layer)
- Windows, macOS, Linux
- Android, iOS (mobile)
- Manages hardware and applications

FIRMWARE (Hardware level)
- Boot code
- Device drivers
- BIOS/UEFI

DECIMAL (Base 10 - Human friendly)
Used: 0-9
Example: 255 in decimal

BINARY (Base 2 - Computer friendly)
Used: 0, 1
Example: 255 decimal = 11111111 binary

HEXADECIMAL (Base 16 - Compact notation)
Used: 0-9, A-F
Example: 255 decimal = FF hexadecimal

Why this matters:
- Computer memory measured in KB, MB, GB
- Color codes use hex (#FF0000 = red)
- Network addresses use hex

        ┌─────────────────┐
        │     INPUT       │
        └────────┬────────┘
                 │
        ┌────────▼────────┐
        │   CPU (ALU)     │◄──────┐
        │  Control Unit   │       │
        └────────┬────────┘       │
                 │                │
        ┌────────▼────────┐       │
        │   MEMORY/RAM    │───────┘
        │   (Data + Code) │
        └────────┬────────┘
                 │
        ┌────────▼────────┐
        │    OUTPUT       │
        └─────────────────┘

Key Principle: Code and data stored in same memory
Used in: Almost all modern computers

1. FETCH
   - CPU fetches instruction from memory
   - Instruction register receives instruction
   - Program counter increments

2. DECODE
   - Control unit interprets instruction
   - Identifies what operation to perform
   - Gets operands from memory/registers

3. EXECUTE
   - ALU performs operation
   - Results stored in registers
   - Flags (Zero, Carry, Sign) updated

4. STORE (if needed)
   - Results written back to memory
   - Ready for next instruction

1 BIT: Single 0 or 1
1 BYTE: 8 bits (256 possible values)

KILOBYTE (KB): 1,024 bytes
MEGABYTE (MB): 1,024 KB ≈ 1 million bytes
GIGABYTE (GB): 1,024 MB ≈ 1 billion bytes
TERABYTE (TB): 1,024 GB ≈ 1 trillion bytes

Example: A typical image file is 2-5 MB
         A movie is 700 MB - 4 GB
         Modern hard drives are 500 GB - 2 TB

ASCII (American Standard Code for Information Interchange)
- 7 bits per character
- 128 possible characters (English only)
- Example: 'A' = 65, 'a' = 97

UNICODE
- Can represent any character in any language
- UTF-8: Variable length (1-4 bytes)
- Supports emoji and special symbols
- Modern standard for all text

Developer: Microsoft
Usage: 75% of desktop computers worldwide
Versions: Windows 11 (latest), Windows 10, Windows Server
Pros:
  ✓ Wide software availability
  ✓ Corporate standard
  ✓ Gaming support
Cons:
  ✗ Requires licensing
  ✗ More prone to malware

Developer: Apple
Usage: ~15% desktop, very popular with professionals
Versions: macOS Sonoma (latest)
Pros:
  ✓ Excellent build quality
  ✓ Good for creative work
  ✓ Strong security
Cons:
  ✗ Expensive hardware
  ✗ Smaller software ecosystem
  ✗ Less gaming support

Developer: Community-driven (Open source)
Usage: ~3% desktop, 99% of servers
Distributions: Ubuntu, Fedora, CentOS, Debian
Pros:
  ✓ Free and open source
  ✓ Highly customizable
  ✓ Excellent for servers
Cons:
  ✗ Steeper learning curve
  ✗ Smaller software library
  ✗ Less user-friendly for beginners

ROOT DIRECTORY (C:\ on Windows, / on Linux)
├── System Files
├── Program Files
│   ├── Windows
│   ├── Applications
│   └── Drivers
├── User Files
│   ├── Documents
│   ├── Pictures
│   ├── Music
│   └── Videos
└── Temporary Files

GOOD FILENAMES:
- Document-Final-v2.docx
- ProjectReport-2024-January.pdf
- IMG-2024-01-15-Vacation.jpg

BAD FILENAMES (avoid):
- doc1, doc2
- final_final_FINAL.docx
- NEW FILE (1).xlsx

Why? Helps organization and finding files later

LAN (Local Area Network)
- Connects computers in limited area (home, office)
- Range: ~100 meters
- High speed: 100 Mbps - 10 Gbps
- Example: Office network, Home WiFi

WAN (Wide Area Network)
- Connects computers across large distances
- Range: Worldwide
- Variable speed: 1 Mbps - 1 Gbps
- Example: Internet, Corporate VPN

INTERNET
- Global WAN connecting billions of devices
- Uses TCP/IP protocol
- Decentralized (no single owner)
- Backbone: Fiber optic cables worldwide

IPv4 Address (Current standard):
- 4 numbers (0-255): 192.168.1.1
- Limited addresses (4.3 billion)
- Running out of addresses

IPv6 Address (Future standard):
- 8 groups of hex: 2001:0db8:85a3:0000:0000:8a2e:0370:7334
- Virtually unlimited addresses
- Slowly replacing IPv4

Private IP Ranges (Can't connect to Internet directly):
- 10.0.0.0 - 10.255.255.255
- 172.16.0.0 - 172.31.255.255
- 192.168.0.0 - 192.168.255.255

Public IP Ranges (Connect to Internet):
- Everything else
- Assigned by ISP
- Unique worldwide

WHAT: Collection of documents (web pages)
HOW: Uses HTML, CSS, JavaScript
ACCESS: Web browser (Chrome, Firefox, Safari)
PROTOCOL: HTTP/HTTPS
DIFFERENCE FROM INTERNET:
- Internet = Infrastructure
- WWW = Service running on Internet

SMTP (Send Mail): Sends emails
POP3 (Receive): Downloads emails (deletes from server)
IMAP (Receive): Syncs emails (keeps on server)

Email Address Structure:
user@domain.com
└─ Username @ Domain

Purpose: Transfer files between computers
Types:
- FTP: Unencrypted (avoid for sensitive data)
- SFTP: Encrypted (secure)
Use cases:
- Uploading website files
- Downloading large files
- Backup transfers

MALWARE
- Viruses: Self-replicating programs
- Worms: Spread through networks
- Trojans: Disguised as legitimate software
- Spyware: Track user activity
- Ransomware: Encrypt files for money

PHISHING
- Fake emails pretending to be legitimate
- Try to steal credentials
- Example: "Click to verify your bank account"

SOCIAL ENGINEERING
- Manipulate people into giving information
- Examples: Pretending to be IT support

DOS/DDOS ATTACKS
- Flood server with requests
- Make website unavailable

✓ Use strong passwords (8+ chars, mix upper/lower, numbers, symbols)
✓ Enable two-factor authentication
✓ Keep software updated (security patches)
✓ Use antivirus software
✓ Don't click suspicious links
✓ Verify email senders carefully
✓ Use VPN on public WiFi
✓ Backup important data
✓ Be skeptical of unsolicited requests

IT SUPPORT: Help users with technical issues
- Salary: $35,000 - $55,000
- Skills: Troubleshooting, communication

SYSTEM ADMINISTRATOR: Manage network and servers
- Salary: $50,000 - $80,000
- Skills: Linux/Windows, networking

NETWORK ENGINEER: Design and maintain networks
- Salary: $60,000 - $100,000+
- Skills: Routing, switching, firewalls

IT SECURITY: Protect systems from attacks
- Salary: $60,000 - $120,000+
- Skills: Encryption, penetration testing

IT PROJECT MANAGER: Oversee IT projects
- Salary: $70,000 - $130,000+
- Skills: Leadership, planning

1. What is the difference between data and information?
2. Name three input devices.
3. What are the main components of a CPU?
4. Explain the difference between LAN and WAN.
5. What is an IP address?
6. List three common digital threats.
7. What does HTTPS provide that HTTP doesn't?
8. Explain what a firewall does.
9. What is the purpose of an operating system?
10. Describe the fetch-decode-execute cycle.