~/Information & Communication Technology Skills – II

Refresher — Hardware & Software

A computer system has two main parts:

1.1 What is an Operating System?

🔹 Main Functions of an Operating System

• Boot and load the system when the computer is switched on.
• Manage hardware — CPU, memory, disk, printer, keyboard, mouse.
• Manage files — creating, naming, saving, copying, deleting.
• Run applications — browsers, games, office tools, media players.
• Provide a user interface — menus, icons, windows, taskbar.
• Enforce security — login IDs, passwords, permissions.

1.2 Classes of Operating Systems

Operating systems are classified based on how many users they support, how many tasks they can run simultaneously, and the device type.

🔹 Popular Operating Systems at a Glance

1.3 The Desktop — Menu, Icons & Taskbar

🔹 Parts of the Desktop

1.4 Starting & Shutting Down a Computer

⚡ 1. Starting the Computer

1. Press the Power button on the CPU / laptop.
2. The BIOS (Basic Input/Output System) runs a Power-On Self-Test (POST) to check the hardware.
3. If the self-test is fine, BIOS loads the Operating System.
4. The login screen appears.
5. Enter your username and password.
6. The desktop appears and the computer is ready.

🔐 2. Login & Logout

Just like a cupboard is locked at home, we keep our computer locked with a login-ID and password. The password is the "key" — only an authorised person can use the system. When you finish working, log out or sign out so that no one else can see your work.

⏻ 3. Shutting Down

1. Close all open applications.
2. Click Start → Shut Down (Windows) or the Systems icon → Shut Down (Ubuntu).
3. The OS closes all background programs and turns off the computer.

1.5 Using the Keyboard

🔹 Groups of Keys

1.6 Using the Mouse

A mouse is a small pointing device used to move, select and open items on the screen. It has a left button, a right button and usually a scroll wheel.

1.7 Files, Folders & the File System

🔹 File Names & Extensions

Every file has a name and an extension separated by a dot (.) — the extension tells the computer what type of file it is.

🔹 File Operations

1.8 File Organisation & Directory Structure

🔹 Tree Structure Example

C: (Root drive)
├── Users
│   └── Vivek
│       ├── Documents
│       │   ├── School
│       │   │   ├── English.docx
│       │   │   └── Maths.docx
│       │   └── Projects
│       ├── Pictures
│       └── Music
├── Program Files
└── Windows

🔹 Key Concepts of a File System

1.9 Creating & Managing Files and Folders

📝 1. Creating a New File (Example: Text File)

1. Open a text editor — gedit in Ubuntu or Notepad in Windows.
2. Type the content — e.g., "Neha Tiwari, Shakti Nagar, New Delhi, 7856453451".
3. Click File → Save (or press Ctrl+S).
4. Choose the location (e.g., Desktop), type a name (e.g., Neha) and click Save.

📁 2. Creating a New Folder

1. Open File Explorer (Windows) or Files (Ubuntu).
2. Go to the location (e.g., Desktop).
3. Right-click in an empty area → New Folder.
4. Type the folder name (e.g., Demo) and press Enter.

✏️ 3. Renaming a File or Folder

Right-click on the item → Rename → type the new name → press Enter. Shortcut: select the item and press F2.

🗑️ 4. Deleting & Restoring

• Select the item → press Delete. It goes to the Recycle Bin (Windows) / Trash (Ubuntu).
• To recover: open Recycle Bin → right-click the item → Restore.
• To delete permanently: press Shift + Delete, or empty the Recycle Bin.

📦 5. Copying vs Moving

🔹 Common Keyboard Shortcuts

2.1 Why Care & Maintenance Matter

Taking care of computers (and mobile phones) helps them work properly and last longer. A computer is a delicate machine with many moving electronic parts — it must be protected from dust, heat, moisture and damage. Regular care saves money because you don't need to buy new devices frequently.

2.2 Cleaning Computer Components

⌨️ 1. Keyboard

• Never eat over a keyboard — crumbs damage internal parts.
• Clean with a soft brush to remove dust and crumbs.
• Turn the keyboard upside down and shake gently to remove loose particles.
• Use a slightly damp (not wet) non-abrasive cloth for stains on key caps.

🖥️ 2. Screen / Monitor

• Wipe the screen with a soft, dry microfibre cloth to remove fingerprints.
• Never spray liquid directly on the screen — dampen the cloth instead.
• Do not use paper towels or tissues — they can scratch.

🍔 3. Be Careful with Food & Drinks

Avoid eating or keeping glasses of water / cups of coffee near the computer. Any liquid spilt can spoil an electronic device beyond repair.

💼 4. Handle Devices Carefully

• Move your laptop carefully and avoid dropping or banging it.
• Even a short fall can damage the screen or hard disk.
• Use a cover for mobiles and a padded case for laptops.

🌡️ 5. Keep the Computer Cool

• Overheating damages internal parts. The CPU has an internal fan — make sure it works.
• Avoid leaving devices in direct sun or in a closed car.
• When using a laptop on a bed, don't cover the fan vents.
• You can use an external cooling pad.

🔋 6. Do Not Overcharge the Battery

Leaving a device plugged in for a long time after it is fully charged can overheat the battery and reduce its life. Always unplug at 100%.

🔌 7. Plug in Devices Carefully

Any device — USB drive, headphones, charger — should be plugged in gently. Don't force a cable into a port. If it doesn't fit, change the direction.

⏳ 8. Don't Run Too Many Programs at Once

When too many programs run simultaneously, the computer slows down and may even crash. Close apps you are not using.

2.3 Preparing a Maintenance Schedule

A maintenance schedule keeps the computer running in perfect condition for a long time. Break tasks into daily, weekly, monthly and yearly:

2.4 Backing Up Your Data

🔹 Common Backup Devices

• External Hard Disk / SSD — large capacity, portable.
• USB Pen Drive — quick and simple.
• CD / DVD — archival storage.
• Cloud Storage — Google Drive, OneDrive, Dropbox — accessible from anywhere.

2.5 Protecting the Computer Against Viruses

🔹 Major Types of Viruses & Threats

2.6 Scanning & Cleaning Viruses

🛡️ 1. Install Anti-virus & Firewall

Anti-virus software monitors data entering and leaving the computer, prevents viruses from getting in and can detect and clean viruses that have already entered. Examples: Windows Defender, Avast, AVG, Kaspersky, Norton, Quick Heal.

🔍 2. Run Regular Virus Scans

• Quick scan — checks common infection points (weekly).
• Full scan — checks every file on the computer (monthly).
• Scan USB drives immediately when connected.

🚫 3. Safe Browsing Habits

• Do not download files from unknown websites.
• Do not open email attachments from unknown senders.
• Keep the OS and browser updated.
• Look for https:// and a padlock icon before entering any card / account details.

2.7 Increasing Computer Performance — Cleaning Junk

Over time, the computer accumulates unnecessary files — temporary files, old images, duplicate downloads. These use up hard-disk space and slow the machine down.

🔹 What to Clean

2.8 Removing SPAM

🔹 How to Deal with SPAM

• Never respond to SPAM mail — responding signals your address is active.
• Delete SPAM regularly.
• Set filters in email settings to block suspicious senders.
• Most email apps have a dedicated SPAM folder — mails are moved there automatically.
• Mark unknown mails as "Report SPAM" so the filter learns.

2.9 Computer Security & Privacy

🔹 Why Security Matters

We store a lot of information on our computers — photos, personal details, financial records, medical records. If this information is leaked or lost, it can cause serious harm — financial loss, identity theft, reputational damage.

🔹 Types of Threats

🕵️ 1. Theft

Stealing information or hardware — of three kinds:

• Physical theft — someone steals your desktop or laptop.
• Identity theft — a hacker steals your personal info and assumes your identity to access accounts or do illegal activity.
• Software piracy — using or distributing unlicensed / unauthorised copies of a program.

🦠 2. Virus

As covered in 2.5 — programs that damage or steal data (worms, Trojans, malware).

2.10 Measures to Protect Data

🔐 1. Strong Passwords

Use passwords that are difficult to guess — a mix of:

• Small letters (a, b, c, d)
• Capital letters (H, J, E, R)
• Numbers (8, 7, 6, 5)
• Special characters (%, ^, #, $)

🛡️ 2. Install Anti-virus & Firewall

These monitor data coming in and going out of the computer and block viruses. Firewall also prevents unauthorised network access.

🔒 3. Encrypt Data

Banks and companies encrypt important data. A decryption password (or key) is needed before the data can be read. Windows has the BitLocker feature for whole-disk encryption.

🌐 4. Use Secure Sites Only

Give credit card or bank details only on secure sites. Check the address bar — it should begin with https:// and show a padlock icon.

🧑‍💻 5. Other Safe Habits

• Lock your computer when you leave it (Windows: ⊞ + L).
• Do not share login IDs or OTPs with anyone.
• Do not click suspicious links in emails or messages.
• Keep the OS, browser and anti-virus up to date.
• Back up important data regularly.
• Do not install pirated software.