Short notes : [2.5+2.5] a) URL b) Mobile computing

a) URL (Uniform Resource Locator)

A URL (Uniform Resource Locator) is a standardized address used to locate and access resources on the internet. It specifies the location of a webpage, file, or service and is a fundamental component of web browsing.

Structure of a URL

A typical URL consists of the following components:

Protocol://Domain Name:Port/Path/Filename?Query#Fragment

• Protocol (Scheme): Defines the communication protocol (e.g., http, https, ftp).
• Domain Name: Identifies the server (e.g., www.example.com).
• Port: Specifies the network port (optional, default: 80 for HTTP, 443 for HTTPS).
• Path: Specifies the location of the resource on the server (e.g., /images/logo.png).
• Query: Contains query strings for dynamic content (e.g., ?id=123).
• Fragment: Refers to a specific section within a webpage (e.g., #section1).

Example of a URL:

https://www.example.com:8080/images/logo.png?id=123#top

• https → Secure HTTP protocol
• www.example.com:8080 → Domain and port
• /images/logo.png → Path to the file
• ?id=123 → Query parameter
• #top → Fragment identifier

Importance of URL:

• Enables web browsers to locate and retrieve resources.
• Used in hyperlinks for navigation.
• Supports resource sharing across networks.

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b) Mobile Computing

Mobile computing refers to the use of portable devices (e.g., smartphones, tablets, laptops) to access and process information while on the move. It integrates wireless communication, mobile hardware, and software to provide computing services anytime, anywhere.

Key Features of Mobile Computing:

1. Portability: Devices are lightweight and easy to carry.
2. Wireless Connectivity: Uses technologies like Wi-Fi, Bluetooth, 4G/5G, and NFC for internet access.
3. Battery-Powered: Relies on rechargeable batteries for operation.
4. Touchscreen & Gestures: Modern mobile devices use touch interfaces for user interaction.
5. Cloud Integration: Supports cloud storage and remote computing (e.g., Google Drive, iCloud).

Applications of Mobile Computing:

• Communication: Messaging (WhatsApp, SMS), video calls (Zoom, Skype).
• Entertainment: Streaming (Netflix, YouTube), gaming (mobile apps).
• Productivity: Office suites (Google Docs, Microsoft Office Mobile), email clients.
• E-commerce: Online shopping (Amazon, Daraz), digital payments (eSewa, Khalti).
• Healthcare: Fitness tracking (Fitbit), telemedicine apps.

Advantages:

• Flexibility: Access data anytime, anywhere.
• Convenience: Eliminates the need for fixed workstations.
• Cost-Effective: Reduces infrastructure costs for businesses.
• Innovation: Enables new applications like IoT (Internet of Things) and AR/VR (Augmented/Virtual Reality).

Challenges:

• Limited Battery Life: Requires frequent charging.
• Security Risks: Vulnerable to malware, hacking, and data breaches.
• Network Dependency: Performance depends on internet connectivity.
• Small Screen Size: May limit complex tasks compared to desktops.

Mobile computing has revolutionized how people interact with technology, making computing more accessible, efficient, and integrated into daily life.