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TECHNOLOGY 

KembaraXtra- Computer Science-Network Types

4/26/2025

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KembaraXtra- Computer Science-Network Types
This guide summarizes different network types, focusing on their characteristics and applications. Understanding the differences is crucial for grasping networking concepts.
I. Local Area Networks (LANs):
  • Definition: Networks connecting devices within a single building (e.g., home, office).
  • Purpose: Enables communication between devices, servers, printers, etc., within the same physical location.
  • Connection: LANs often connect to WANs to access the internet and external resources.
  • Example: Your home Wi-Fi network.
II. Wide Area Networks (WANs):
  • Definition: Networks connecting LANs across geographically dispersed locations.
  • Purpose: Connects offices, buildings, and ultimately, facilitates global internet connectivity.
  • Relationship to LANs: LANs connect to WANs to access broader networks and the internet.
  • Example: The internet itself is a massive WAN.
III. Wireless Network Technologies:
This section details specific wireless technologies, highlighting their range and applications. Note the distinction between general-purpose networks (LANs, WANs) and more specialized, short-range networks (PANs).
A. Wi-Fi Networks:
  • Type: Wireless LAN (WLAN).
  • Range: Relatively large, covering homes and offices.
  • Purpose: Enables wireless connection of multiple devices (smartphones, laptops, etc.).
  • Further Study: Refer to Chapter 15 ("Wireless Networks") for detailed information.
B. Bluetooth Networks (PANs - Personal Area Networks):
  • Type: Wireless PAN (Personal Area Network).
  • Range: Short range (approximately 30 feet or 10 meters).
  • Purpose: Connects devices within a close proximity for personal use, e.g., connecting peripherals (headsets, car systems) to a single device (computer or smartphone).
  • Network Structure: Peer-to-peer; typically connects a small number of devices.
C. Near-Field Communication (NFC):
  • Type: Wireless PAN (Personal Area Network).
  • Range: Extremely short (a few inches).
  • Purpose: Short-range data transfer and communication, often used for contactless payments and access control.
  • Network Structure: Peer-to-peer; limited range restricts connectivity to very close devices.
IV. Peer-to-Peer Networks:
  • Definition: Networks where devices share resources directly with each other without a central server.
  • Examples: Bluetooth and NFC networks are examples of peer-to-peer networks. They are characterized by their limited range and purpose. They contrast with client-server models typical of LANs and WANs, where a server manages resource access.​
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. Key Differences Summarized:

Network Type

Range

Purpose

Example

LAN

Within a building

Connecting devices within a building

Home Wi-Fi, office network

WAN

Global

Connecting LANs across geographical areas

The Internet

Wi-Fi

Medium

Wireless LAN

Home Wi-Fi

Bluetooth

Short (30 feet)

Connecting personal devices

Wireless headphones, car hands-free system

NFC

Very Short

Contactless payments, access control

Payment terminals, building access cards
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KembaraXtra- Computer Science -  TCP/IP Networking - Basic Networking Concepts

4/26/2025

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KembaraXtra- Computer Science - TCP/IP Networking - Basic Networking Concepts
Objective: Identify basic networking concepts.
Core Concept: Networks connect computer systems, significantly enhancing their capabilities. This connectivity enables various functions beyond the capacity of individual computers.
Key Idea 1: The Power of Connectivity:
  • Individual computers are powerful, but their potential is greatly amplified when connected in a network.
  • Networking's purpose: To link computer systems together, regardless of geographical location (e.g., within an office or globally via the internet).
Key Idea 2: Applications of Networking:
  • Enhanced Capabilities: Networks enable a wide array of applications and tasks impossible for isolated computers. Examples provided include:
    • Email communication: Sending messages globally.
    • Video streaming: Transmission of video content.
    • Shared resources: Accessing resources like printers located remotely.
  • Broader implication: Networking facilitates numerous other crucial tasks (implying a vast and diverse application landscape beyond the examples given).
Study Questions:
  1. Why are networks considered essential for enhancing the capabilities of individual computers?
  2. Give three examples of tasks made possible by computer networks. Explain how each task relies on network connectivity.
  3. What is the fundamental purpose of a network?
  4. Consider the phrase "globally via the internet". What does this highlight about the scale of networking?
Further Study:
  • Research different types of networks (e.g., LAN, WAN).
  • Explore the role of protocols like TCP/IP in enabling network communication.
  • Investigate the infrastructure needed to support various network applications.
Note: This objective focuses on the foundational concept of what a network is and what it does. Further learning will delve into the how (protocols, infrastructure, etc.). Understanding the "why" (the benefits of connectivity) is crucial for grasping the importance of networking.



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KembaraXtra- Computer Science-Wireless Connections

4/26/2025

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KembaraXtra- Computer Science-Wireless Connections
This guide summarizes different types of wireless connections, focusing on their strengths, weaknesses, and typical applications. Understanding the trade-offs between speed, cost, availability, and geographic limitations is crucial.
I. Cellular Connections
  • Technology: Uses cellular networks (e.g., 4G, 5G) provided by cellular carriers.
  • Speed:
    • 5G: Up to 20 Gbps (gigabits per second) – available in major cities, offering extremely high speeds.
    • 4G: Around 14 Mbps (megabits per second) – wider availability, still suitable for many applications.
  • Cost: Generally inexpensive, comparable to typical mobile phone plans.
  • Availability: Wide availability in populated areas; 4G has broader coverage than 5G.
  • Ideal for: Mobile users needing internet access while on the move.
II. Radio Frequency (RF) Fixed Wireless
  • Technology: Point-to-point connection using radio waves between a user's antenna and the ISP's antenna.
  • Speed: Varies greatly depending on distance, signal strength, and technology used; generally slower than cellular.
  • Cost: Can vary widely.
  • Availability: Limited to areas with established RF infrastructure; requires a direct line of sight between antennas.
  • Ideal for: Home users in remote locations where other broadband options are unavailable, providing a fixed connection.
III. Satellite Internet
  • Technology: Uses satellites orbiting Earth to transmit data.
  • Speed: Historically slow and expensive, but improving rapidly. New services like Starlink offer 100 Mbps at reasonable prices.
  • Cost: Prices vary widely; newer services are making it more affordable.
  • Availability: Near-global coverage; accessible even in very remote areas.
  • Ideal for: Users in extremely remote locations where other options are infeasible.
IV. Global Positioning System (GPS) – Not an internet connection
  • Technology: Uses signals from multiple satellites to determine a device's location.
  • Purpose: Location tracking and navigation; not for internet access.
  • Key Feature: Provides precise location data.​
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. Comparison Table:

Connection Type

Speed

Cost

Availability

Ideal for

Cellular

14 Mbps - 20 Gbps

Inexpensive

Wide (4G > 5G)

Mobile users

Fixed Wireless

Variable

Variable

Limited, line-of-sight

Remote homes

Satellite

Increasing

Variable

Near-global

Extremely remote locations

GPS

N/A

Usually included

Near-global

Location tracking/navigation
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KembaraXtra- Computer Science-Internet Connection Service Types

4/26/2025

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KembaraXtra- Computer Science-Internet Connection Service Types
This guide summarizes different internet connection types, focusing on speed and suitability. Understanding the differences is crucial for choosing the optimal service for a given need.
I. Broadband Connections: The Modern Standard
All current internet connections are broadband – always-on and significantly faster than dial-up. However, speeds vary considerably. Exam questions may ask you to identify the best service type for a scenario, so consider multiple options and their suitability.
II. Obsolete Technology: Dial-Up Modems (For Contextual Understanding)
  • Mechanism: Used standard copper telephone lines, transmitting data via audio signals. Incredibly slow.
  • Speed: Extremely slow (e.g., 300 bits per second in the 1980s – about 38 characters per second). This is far slower than modern connections.
  • Relevance: Primarily serves as a comparison to highlight the advancements in broadband technology. It's not used anymore.

. III. Modern Broadband Connection Types:

Connection Type

Medium

Speed

Pros

Cons

Suitability

DSL (Digital Subscriber Line)

Copper Telephone Lines

~10 Mbps (low)

Always-on, readily available (in some areas)

Slowest among modern options

Homes and small businesses with limited needs

Cable

Coaxial Cable

1 Gbps and beyond

Relatively fast, widely available

Speed can fluctuate depending on network load

Homes and businesses, good balance of speed and cost

Fiber Optic

Fiber-optic Cable

Multi-gigabit

Fastest available, virtually limitless potential

Installation can be expensive and availability may be limited

Businesses and homes demanding high bandwidth (e.g., streaming, gaming)
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Key Differences Summarized:
  • DSL: Uses existing phone lines, offering an always-on, but slower connection.
  • Cable: Uses coaxial cables (TV cables), providing faster speeds than DSL but potentially slower than fiber. Speed can be impacted by network congestion.
  • Fiber Optic: Uses glass fibers and lasers for exceptionally high speeds, but may have higher initial installation costs and limited availability in certain areas.
Exam Tip Recap: Exam questions often involve selecting the best connection type for a specific situation. Consider the organization's needs (bandwidth requirements, budget, availability of different services in the area) when making your choice. Remember that multiple options might be possible, but only one will be the best fit.



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KembaraXtra- Computer Science - Internet Serivce Types

4/26/2025

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KembaraXtra- Computer Science - Internet Serivce Types
This study guide summarizes the provided text on Internet service types for organizations, focusing on key concepts for effective understanding and recall.
I. Core Concept: Connecting Internal Networks to the Internet
  • Internal Networks: Organizations use internal networks to connect their computers and devices within a single location (building, campus) or across multiple locations.
  • Internet Connectivity: The true power of these internal networks is unlocked by connecting them to the internet, enabling global communication and access.
  • Internet Service Providers (ISPs): Organizations achieve internet connectivity by contracting with ISPs. Understanding the different service types offered by ISPs is crucial for IT professionals.
II. Key Term: Internet Service Providers (ISPs)
  • Definition: Companies that provide organizations with the infrastructure and services necessary to connect their internal networks to the internet.
  • Importance: Choosing the right ISP and service type is critical for ensuring reliable, secure, and efficient internet access for an organization.
III. Study Points & Actionable Tasks:
  • Further Research: The provided text only introduces the concept of different ISP service types. Your next step is to research the specific types of internet service offered by ISPs. This should include a comparison of:
    • Bandwidth: The amount of data that can be transferred per unit of time (e.g., Mbps, Gbps). Consider the impact of bandwidth on application performance and user experience.
    • Latency: The delay in data transmission. Low latency is crucial for real-time applications.
    • Reliability: The consistency and uptime of the service. Consider service level agreements (SLAs) offered by ISPs.
    • Cost: The pricing models offered by different ISPs (e.g., fixed monthly fee, usage-based pricing).
    • Security features: Investigate security measures offered by different ISPs to protect against cyber threats. Consider options like firewalls and intrusion detection systems.
  • Comparative Table: Create a table comparing at least three different types of internet service (e.g., DSL, Cable, Fiber, Satellite, MPLS). Include columns for Bandwidth, Latency, Reliability, Cost, and Security Features. This will help you visualize and contrast the different options.
  • Case Study: Research a real-world example of an organization choosing an ISP and the factors that influenced their decision. Analyze the pros and cons of their choice.
By completing these tasks, you will solidify your understanding of the fundamental role of ISPs in connecting organizational networks to the internet and gain a deeper appreciation for the diverse range of service options available. Remember to focus on the practical implications of each service type for different organizational needs.



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KembaraXtra- Computer Science - Computing

4/26/2025

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KembaraXtra -Computer Science - Cloud Computing
This study guide summarizes key concepts of cloud computing, focusing on definitions, drivers, service models, and deployment models. It's designed for thorough understanding and exam preparation.
I. Core Concepts of Cloud Computing
A. Definition:
  • NIST Definition: Cloud computing is a model for enabling ubiquitous, convenient, on-demand network access to a shared pool of configurable computing resources (networks, servers, storage, applications, services) that can be rapidly provisioned and released with minimal management effort. This is the most academically accepted definition. Simply put, it's the delivery of computing services over a network.
B. Drivers of Cloud Adoption:
  • On-Demand Self-Service: Immediate access to resources, significantly increasing agility. This contrasts sharply with the traditional procurement and setup processes of on-premise hardware.
  • Scalability: Ability to easily increase capacity to meet demand.
    • Horizontal Scaling: Adding more servers.
    • Vertical Scaling: Increasing the capacity of existing servers (CPU, memory).
  • Rapid Elasticity: Dynamically scaling resources up or down based on fluctuating needs. This is closely related to scalability but emphasizes the speed and responsiveness of resource allocation.
  • Broad Network Access: Accessible via internet from anywhere.
  • Measured Service: Usage is metered, allowing for precise billing based on consumption. This promotes efficient resource management and cost optimization.
II. Cloud Service Models
This section details the four major cloud service models:
A. Software as a Service (SaaS):
  • Definition: The provider delivers a complete application to customers. Customers don't manage infrastructure; they simply use the service.
  • Examples: Google Workspace, Microsoft 365, Dropbox, Box, specialized applications like credit card processing.
  • Key Feature: Minimal to no configuration required on the customer's side.
B. Infrastructure as a Service (IaaS):
  • Definition: Customers purchase basic computing resources (compute, storage, networking) and build their own solutions.
  • Major Providers: AWS, Microsoft Azure, Google Cloud Platform.
  • Key Feature: Provides maximum control and flexibility for infrastructure management.
C. Platform as a Service (PaaS):
  • Definition: Provides a platform for running application code without managing servers. It sits between IaaS and SaaS.
  • Key Feature: Offers a balance between control (running your own code) and ease of management (no server management).
D. Desktop as a Service (DaaS):
  • Definition: Virtualized desktops accessed remotely. Enables flexible remote work arrangements.
  • Examples: Amazon WorkSpaces, on-premise DaaS solutions.
  • Key Feature: Enables accessing a full desktop environment from any device with internet access.
III. Cloud Deployment Models
This section covers the three primary deployment models:
A. On-Premises/Private Cloud:
  • Definition: Organization builds and manages its own cloud infrastructure, either internally or with a partner.
  • Rationale: Maintain control over data and resources. Not sharing infrastructure with other organizations.
B. Public Cloud:
  • Definition: Multi-tenancy model where resources are shared among many customers.
  • Key Concept: Multitenancy: Many customers share the same physical hardware. Isolation mechanisms are crucial for security and performance.
  • Challenges: Potential for performance degradation if simultaneous resource demands exceed capacity.
C. Hybrid Cloud:
  • Definition: Combines public and private cloud environments.
  • Rationale: Leverage benefits of both models – public cloud for scalability and cost-effectiveness, private cloud for sensitive data.

. Key Terms Summary

Term

Definition

Cloud Computing

Delivery of computing services over a network.

On-Demand Self-Service

Immediate access to cloud resources.

Scalability

Ability to easily increase or decrease capacity.

Elasticity

Dynamically adjusting capacity based on fluctuating demand.

Measured Service

Usage-based billing for cloud resources.

SaaS

Software as a Service (complete application provided).

IaaS

Infrastructure as a Service (basic computing resources).

PaaS

Platform as a Service (platform for running application code).

DaaS

Desktop as a Service (remotely accessed virtual desktops).

Multitenancy

Multiple customers sharing the same physical hardware in a public cloud environment.

Private Cloud

Cloud infrastructure owned and managed by a single organization.

Public Cloud

Cloud infrastructure shared among multiple organizations.

Hybrid Cloud

Combination of public and private cloud environments.

This

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KembaraXtra – Computer Science - Hypervisor

4/26/2025

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Hypervisors: A Study Guide
This guide summarizes the key concepts of hypervisors, aiming for comprehensive understanding.
I. Core Concept:
Virtualization uses a host machine (with physical hardware) to run multiple guest machines (each with its own operating system). This is achieved using a hypervisor, software that manages the guest machines and makes each believe it has exclusive access to the hardware, even though they share the host's resources. Guest OSes remain unaware of their virtualized nature.
II. Types of Hypervisors:
Two main types exist, differing in how they interact with the host hardware:
  • Type 1 Hypervisor (Bare-Metal Hypervisor):
    • Runs directly on the host's hardware.
    • Guest OSes run directly on top of the hypervisor.
    • Common Use Cases: Data centers, Infrastructure-as-a-Service (IaaS) providers. This is the dominant type in large-scale environments. While the user might not directly interact with it, it is the underlying technology for many cloud services.
    • Key Advantage: Greater performance and efficiency due to direct hardware access.
  • Type 2 Hypervisor:
    • Runs on top of a host operating system (e.g., Windows, macOS, Linux).
    • The host OS acts as an intermediary between the hypervisor and the hardware.
    • Common Use Cases: Personal computers, desktop virtualization.
    • Examples: VirtualBox, Parallels.
    • Key Advantage: Easier to install and manage due to the existing host OS. Less resource intensive than Type 1 (in most cases) but overall less efficient.
III. Enterprise vs. Personal Use:
  • Enterprise: Primarily uses Type 1 hypervisors for their scalability, performance, and efficiency in managing large numbers of virtual machines within data centers and IaaS environments. The hypervisor is typically managed by the data center operator (or the IaaS provider), not the end user.
  • Personal: Type 2 hypervisors are more prevalent, offering a simpler approach to running multiple operating systems on a single machine.​
V. Study Questions:
  1. Explain the fundamental concept of virtualization using the terms "host machine," "guest machine," and "hypervisor."
  2. What are the key differences between Type 1 and Type 2 hypervisors? Provide examples of each.
  3. Why are Type 1 hypervisors preferred in enterprise environments?
  4. In a cloud computing context, who is responsible for managing the hypervisor?
  5. What are the trade-offs between Type 1 and Type 2 hypervisors in terms of performance, resource utilization, and ease of management?
By understanding these concepts and answering these questions, you will have a solid grasp of hypervisor technology. Remember to focus on the core difference: how the hypervisor interacts with the underlying hardware.


II. Types of Hypervisors:

We categorize hypervisors into two main types based on their architecture:

Type

Description

Location/Use Case

Examples

Type 1 (Bare-Metal)

Runs directly on the physical hardware. No underlying OS.

Data centers, IaaS providers (e.g., AWS, Azure)

VMware ESXi, XenServer, KVM

Type 2 (Hosted)

Runs as a program on top of an existing operating system.

Personal computers, desktops

VirtualBox, Parallels, VMware Workstation Player

III. Key Differences Summarized:

Feature

Type 1 (Bare-Metal)

Type 2 (Hosted)

Location

Directly on hardware

On top of an OS

Performance

Generally faster

Slightly slower due to OS overhead

Resource Use

More efficient resource use

Less efficient resource use

Complexity

More complex to manage

Easier to manage and set up

Common Use

Data centers, Cloud

Personal computers
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KembaraXtra- Computer Science - Virtual Servers

4/26/2025

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KembaraXtra- Computer Science - Virtual Servers
I. The Inefficiency of Traditional Client/Server Models:
  • Problem: The traditional client/server model led to significant wasted resources. Servers often sat idle for extended periods, waiting for increased activity. This represents a considerable inefficiency in terms of hardware utilization and cost.
II. The Rise of Virtualization:
  • Solution: Virtualization technology emerged as a solution to this inefficiency. It allows multiple virtual servers to share the same physical hardware (e.g., CPU, RAM, storage). This means one physical server can host many virtual servers.
  • Key Benefit: This shared hardware approach allows for dynamic allocation of resources. Memory, storage, and processing power can be shifted as needed to meet demands, optimizing resource utilization and eliminating idle server time. This significantly improves efficiency.
III. Key Players in Virtualization:
  • Examples: Major virtualization platforms include VMware and Microsoft Hyper-V. These platforms provide the software necessary to create and manage virtual servers.
IV. Key Concepts to Remember:
  • Virtual Server: A software-based emulation of a physical server. Multiple virtual servers can exist on a single physical machine.
  • Virtualization: The process of creating and managing virtual servers.
  • Resource Allocation: Dynamic assignment of resources (CPU, RAM, storage) to virtual servers based on current needs.
  • Efficiency: Virtualization significantly improves efficiency by reducing wasted resources and optimizing hardware utilization.
V. Study Questions:
  1. Explain the inefficiency inherent in the traditional client-server model.
  2. How does virtualization address the inefficiencies of the traditional client-server model?
  3. What are the key benefits of using virtualization technology?
  4. Name two examples of virtualization platforms.
  5. Define "virtual server" and explain how it differs from a physical server.
VI. Further Research:
  • Investigate the different types of virtualization (e.g., Type 1 vs. Type 2 hypervisors).
  • Research the advantages and disadvantages of using virtual servers.
  • Explore the security considerations involved in virtual server environments.
This study guide provides a comprehensive overview of virtual servers and their importance in modern computing. By understanding the concepts presented here and answering the study questions, you will gain a solid foundation in this crucial area of technology.



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KembaraXtra Computer Science - The Shift from Mainframes to Client/Server Computing

4/26/2025

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KembaraXtra Computer Science - The Shift from Mainframes to Client/Server Computing
This study guide summarizes the evolution of enterprise computing, focusing on the transition from mainframe-centric systems to client/server architectures.
I. The Mainframe Era:
  • Characteristics: Enterprise computing was centralized in data centers around large, powerful mainframes. Management required specialized personnel and was complex. This system served as the organization's central computing resource.
  • Limitations: Access to computing resources was limited, requiring users to go through the mainframe. Maintenance and management were intensive and costly.
II. The Rise of Client/Server Computing (1980s-1990s):
  • Key Change: A paradigm shift from centralized mainframe computing to a decentralized client/server model.
  • Benefits:
    • Decentralized Computing Power: Computing power moved to individual desktops (clients), empowering users to perform tasks locally. This reduced reliance on the mainframe for basic operations.
    • Improved Centralized Computing: Dedicated servers handled specific functions, leading to better organization and manageability of the data center compared to the complexity of managing a single mainframe. This allowed for easier maintenance and improved efficiency.
  • Overall Impact: The shift to client/server architectures significantly improved efficiency, accessibility, and manageability of enterprise computing resources. It laid the groundwork for future developments in IT infrastructure.
III. Key Terms & Definitions:
  • Mainframe: A large, powerful central computer that served as the primary computing resource for an organization in the pre-client/server era.
  • Client/Server Computing: A distributed computing model where clients (individual computers) request services from servers (centralized computers providing specific functions).
  • Data Center: A facility housing computer systems and associated components for an organization.
IV. Study Questions:
  1. Explain the limitations of mainframe-based computing.
  2. Describe the key benefits of the shift to client/server architecture.
  3. How did client/server computing change the role of the data center?
  4. What were the main drivers behind the move away from mainframes?
  5. Contrast the centralized nature of mainframe computing with the distributed nature of client/server architecture.
V. Further Research: (Optional)
Research the impact of virtualization on further decentralizing and improving the efficiency of client/server architectures. Explore how cloud computing built upon this foundation.



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Computer Science - Wireless Display Technology

3/29/2025

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Computer Science - Wireless Display Technology
Users may wish to wirelessly project material onto other devices, utilizing two available methods for this purpose. Screen mirroring enables the replication of your computer's display on an alternate screen. This is advantageous during presentations. Casting is a method that facilitates the transmission of multimedia content between devices. This is frequently utilized to transmit video from a mobile device to a larger display.


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