Introduction to Computers, File Management, and Computational Thinking

Input: Providing data or instructions (e.g., via keyboard, mouse, or touchscreen).
Processing: The computer performing work on the data via the CPU (Central Processing Unit).
Output: Displaying results (e.g., on a screen or printer).
Storage: Keeping data and instructions permanently.
Communication: Allowing computers to share information with other devices.
Hardware: Physical components like the keyboard and screen.
Software: Programs or specifically designed instructions; includes the Operating System (Windows, macOS, Android, iOS) and Apps (word processors, spreadsheets).
Processor and Memory:
- CPU: The "brain" of the computer that carries out instructions.
- RAM (Random Access Memory): Temporary memory where active data is loaded. Contents are lost if power is removed.
Storage Capacity: Measured in Gigabytes (GB) and Terabytes (TB).
- $1 ext{ TB} = 1000 ext{ GB}$
Storage Devices:
- HDD (Hard Disk Drive): Moving parts, slower, but cheaper.
- SSD (Solid State Drive): No moving parts, faster, but more expensive.
- Flash Drives: Small electronic storage using USB ports.
- Memory Cards: Common formats include SD and Micro SD.
- Optical Drives: Uses CDs or DVDs; considered "old technology."

Input Devices:
- Keyboard and Mouse/Touchpad: Most common input methods.
- Digital Camera: Stores photos and videos.
- Scanner: Converts "hard copy" into digital format.
- Microphone: Inputs live sound.
Output Devices:
- Monitor/Screen: Provides "soft copy" visual output.
- Printer: Creates a permanent "hard copy."
- Speakers/Headphones: Sound output.
- Data Projector: Projects images onto a large screen.
Communication Devices:
- Router: Connects devices to the internet via cables or WiFi.
- Cellular Technology: Uses cellphone signals for mobile data, calls, and SMS.

File Explorer: The program used to manage files and folders, divided into a navigation pane (left) and contents pane (right).
Organization: Files are grouped in folders; folders within folders are subfolders.
Selection Shortcuts:
- Adjacent files: Click first file, hold Shift, click last file.
- Non-adjacent files: Click first file, hold Ctrl, click each additional file.
File Actions:
- Copying: $ext{Ctrl+C}$
- Cutting: $ext{Ctrl+X}$
- Pasting: $ext{Ctrl+V}$
- Rename: Right-click and choose Rename (do not change the file extension after the dot).
Sorting: Use Details view to sort by Name, Date modified, Type, or Size.

The Internet vs. WWW: The internet is the global network; the World Wide Web (WWW) is a service on that network consisting of linked web pages.
URLs: Unique addresses for web pages.
Search Engines: Tools like Google or Bing used to find information using keywords.
- Tips: Use quotation marks for exact phrases (e.g., $" ext{African rivers}"$ ); use keywords rather than full sentences.
Web Browser Features:
- History: Accessed via $ext{Ctrl+H}$ to see past sites.
- Tabbed Browsing: Opening multiple results in separate tabs to avoid clicking back and forth.
Safety: Be wary of malware on free download sites.

Device Security: Use hard-to-guess PINs, patterns, or passwords (avoid "12345").
Authentication:
- CAPTCHA: A test to distinguish humans from robots.
- Two-factor authentication: Using a password plus a code sent to a phone.
Passwords: Length is critical. Use a passphrase (a short personal sentence like $i ext{LOVEmyc@toreo1}$ ) rather than single words.
Identity Theft: Stealing personal data (ID, passwords, name) to access bank accounts or credit.
Phishing: Criminals using fake emails from "trusted" sources (like banks) to trick users into revealing info.
Hacking: Unauthorized access via system loopholes or public WiFi "man-in-the-middle" attacks.

Decomposition: Breaking a large task into smaller, manageable sub-steps.
Sequence: The specific, logical order in which steps must be performed. Computers cannot fill in missing details or correct wrong orders.
Abstraction: Focusing only on essential parts of a problem and ignoring irrelevant details.
Pattern Recognition: Identifying repeated actions to simplify instructions.
- Example: Drawing a square involves repeating "Draw line, Turn $90^{ ext{circ}}$ " four times.
Algorithms: A series of instructions followed in order to solve a problem or accomplish a task.

Why must work be saved to storage before switching off? RAM is temporary; data disappears if power is lost. Storage is permanent.
Why use "Shut down" instead of the power button? Turning off via the button can damage open files and prevent changes from being saved.
Is a touchscreen an input or output device? Both; it displays information (output) and receives touch commands (input).
What is the purpose of a CAPTCHA? It is a test to prove the user is a human and not a computer program/robot.
How can phishing be identified? Look for warning signs: strong emotional appeals (fear/excitement), spelling errors, generic greetings, and suspicious links/attachments.
Joe used an algorithm to count his brothers returning from a swim. He started his count at 0 and added 1 for each brother he saw (Mike, John, Pete, Jay, Neo). Total = 5. Why is this wrong? The algorithm didn't count Joe himself; there were six brothers in total.
How does hacking a social media account lead to stealing money? Stolen info can be used for identity theft on other sites, or the hacked account can send phishing links to contacts to spread the scam.