Computer Systems, Input-Output Devices, Storage, and Networking Study Notes

Input and Output Devices

  • Overview of Data Flow:

    • Input Data: Data entering into the computer system.

    • Output Data: Data coming out from the computer system.

  • Input Devices:

    • Mouse: Allows the user to control the cursor on the screen.

    • Keyboard: Allows users to input data such as keywords.

    • Scanner: Scans physical documents into digital format.

    • Webcam: Captures real-time video and image input for a computer system.

  • Output Devices:

    • Projector: Projects light onto a wall or screen to visually display output.

  • Dual-Function Devices (Input and Output):

    • Graphics Tablet: A device used to create animations; functions as both an input and output device.

Processing and Memory Hardware

  • Processor / CPU (Central Processing Unit):

    • Acts as the central processing unit and the "brain" of the computer system.

    • Responsible for processing commands and data.

  • RAM (Random Access Memory):

    • Provides temporary data storage.

    • Classed as volatile memory; when the computer is shut down, all current work and stored data are lost.

Storage Devices

  • Definition: Pieces of computer equipment on which information can be stored permanently or temporarily.

  • Hard Disk Drive (HDD):

    • Provides permanent data storage.

    • Operates as both an input and output mechanism when data is read or written.

    • Cheap with a large storage capacity.

    • Contains mechanical, moving parts.

  • Solid State Drive (SSD):

    • Provides high-speed data access and storage.

    • Expensive compared to traditional storage media.

    • Operates quietly with no moving parts.

  • USB Sticks:

    • Portable flash memory sticks used to save work and transfer files.

  • SD / Memory Card:

    • Compact memory cards inserted into cameras and portable devices for storing pictures and multimedia.

  • Optical Discs (CD / DVD):

    • Storage discs used for holding music, movies, or general data.

Laptop Features and Mobile Devices

  • Laptop Features:

    • Defined as portable, multifunctional computing devices.

    • Features integrated hardware including a separate keyboard, large screen, and touchpad.

    • The combination of input components (keyboard, touchpad) and output components (screen) makes it a complete input and output system.

    • Enables file access from anywhere due to portability.

  • Mobile Device Characteristics:

    • Portability: Highly portable and lightweight design.

    • Power Source: Battery-powered for handheld operational mobility.

    • Architecture: Employs a System on a Chip (SoC) integration.

  • Primary Uses of Mobile Devices:

    • Web browsing and internet access.

    • Playing games.

    • Organizational functions (e.g., calendar, task scheduling).

    • Email access.

    • Entertainment systems (media and video playback).

Communication Systems and Devices

  • Network Fundamentals:

    • A network is defined as 2 or more interconnected computers.

    • Communication systems and devices are used to move and transmit data between devices across a network (either wirelessly or through physical cables).

  • Network Interface Card (NIC):

    • Allows data to be moved to and from a computer system via an ethernet cable.

    • Primarily utilized with desktop computers for wired local area connectivity.

  • Wireless Dongles:

    • Enables data transfer and allows devices to connect to a router that is part of a LAN (Local Area Network).

    • Connects devices to a mobile broadband network.

    • Typically used with laptops to provide mobile internet access.

  • Routers:

    • Directs data packets to their correct destination over a large network.

    • Required whenever 2 networks meet to direct the data in the proper direction along the next network segment.

Electronic Point of Sale (EPOS) Systems

  • Definition:

    • Electronic Point of Sale (EPOS) represents self-service automation in retail environments.

  • Step-by-Step EPOS Transaction Process:

    1. Product Selection: A customer enters a shop and selects their desired items.

    2. Barcode Scanning: The customer scans each item's barcode using a barcode scanner.

    3. Information Retrieval: The EPOS system processes the scanned barcode to retrieve item information, such as pricing and item name.

    4. Payment: Once all items are scanned, the customer pays by scanning their card.

    5. Receipt Issuance: The customer receives a physical printed receipt following successful payment verification.