Hardware and software

• A computer receives input, processes it, and produces output.
• Computers have hardware and software components.

Hardware and Software

• Hardware is the physical components of a computer system, either external or internal.

External Hardware

• External hardware refers to devices visible to the user.
• Examples include mice, keyboards, monitors, printers, and scanners.

Internal Hardware

• Internal hardware consists of devices inside the computer, not normally visible.
• Examples include the CPU/Processor, Motherboard, RAM, ROM, Graphics Card, Sound Card, and Internal HDD/Internal SSD.
• The motherboard enables communication between the processor and other hardware.

Software

• Software is programs that control a computer system's operation and process electronic data.
• Software is divided into Application and System types.

Application Software

• Application software provides services for users to solve tasks.
• Examples include word processors, spreadsheets, database management systems, and graphics/video/audio editing software.

Apps

• Apps are programs for smartphones or tablets.

System Software

• System software provides services required for a computer to run properly.
• Examples include operating systems (OS), device drivers, compilers, linkers, and utilities like anti-virus software.

Main Hardware Components

• Key hardware components include the CPU, main memory, input, and output devices and secondary storage.

Central Processing Unit (CPU)

• The CPU processes instructions to produce output and controls computer operations.
• The CPU controls input/output devices and internal data movement, executes instructions, performs calculations, and makes logical decisions.
• The CPU comprises the Control Unit and Arithmetic Logic Unit (ALU).

Control Unit

• The Control Unit is a CPU component managing interactions between different CPU parts.

Arithmetic Logic Unit (ALU)

• The Arithmetic Logic Unit (ALU) is a CPU component that performs calculations and logical decisions.

Main Memory

• Main memory is internal memory that the CPU can directly access.
• Main memory may also be called primary or internal memory.

Random Access Memory (RAM)

• RAM is volatile memory for temporary storage that can be read from and written to.
• RAM stores in-use instructions, software, data, and parts of the operating system.
• Volatile memory loses its contents when power is off.

Read Only Memory (ROM)

• ROM is non-volatile memory for permanent storage that can only be read from.
• ROM permanently stores start-up instructions, like BIOS, for when the computer is switched on.
• BIOS (Basic Input/Output System) checks if all devices are present and functional.

RAM vs. ROM

• RAM: volatile, temporary storage, can be written to and read from, stores data/software/instructions currently in use, tends to have greater storage capacity.
• ROM: non-volatile, permanent storage, read-only, stores start-up instructions, and has less storage capacity.

Secondary Storage

• Secondary storage is non-volatile, permanently storing data and not directly accessed by the CPU, making it slower than main memory.
• Stores files and software permanently.
• Stores data not currently needed by the CPU and transfers data to other computers.

Input Devices

• Input devices send data to a computer for processing under user control.
• Input devices turns input into a form the computer can understand.
• Input devices design is more complex than output devices.

Output devices

• Output devices receive data from the computer and are controlled by it.
• Output devices display the results of processed data.
• Output devices design is less complex than input devices.

Input vs. Output Devices

• Input: sends data to the computer, turns input into a computer-understandable form, user-controlled, more complex design.
• Output: receives data from the computer, displays processed data results, computer-controlled, less complex design.

Operating Systems

• The operating system allows users to communicate with the hardware and perform basic tasks.
• OS functions include providing a user interface, managing user accounts and peripherals, memory management, and providing system security.

User Interfaces

• Types of user interfaces include Command Line Interface (CLI), Graphic User Interface (GUI), Dialogue-based, and Gesture-based.

Command Line Interface (CLI)

• CLI requires users to type commands to interact with the computer.
• CLI Advantages: uses less memory than GUI, requires less processing power, and the user is not limited to pre-determined options.
• CLI Disadvantages: commands must be learned and memorized, commands must be typed in exactly, prone to errors, and typing is time-consuming.

Graphic User Interface (GUI)

• GUI is built around graphical items and uses a WIMP (windows, icons, menus, pointer) system
• GUI Features: Windows display data, icons represent folders/software, menus list options, and a pointer navigates the screen.
• GUI Advantages: no need to memorize commands, user-friendly, fewer errors, and quicker/simpler due to pointers and icons.
• GUI Disadvantages: consumes more memory, requires more processing power, limits users to provided icons/menus, and protects computer settings.

Dialogue-Based Interface

• Dialogue-based interfaces use speech recognition to interact.
• Dialogue-based interface Advantages: eliminates the need for drivers to remove hands from the steering wheel, safer than a standard interface, useful for people with disabilities and can be used as a security feature.
• Dialogue-based interface Disadvantages: complex to set up, expensive to develop, requires the user to know specific commands, unreliable, distracting if commands not understood, limited access due to the number of stored commands and needs to be trained by the user.

Gesture-Based Interface

• Gesture-based interfaces use human body movements to interact with devices.
• Gesture-based interface Advantages: replaces mechanical input devices, no physical contact, natural interface, and no training needed.
• Gesture-based interface Disadvantages: unintentional activation, less accurate, limited working range, limited number of movements, requires memorization and accurate execution of gestures, and may not be suitable for users with physical disabilities.

Types of Computers

• Types of computers: desktop computers and mobile computers.

Desktop Computers

• Desktop Advantages: less prone to theft, better specifications for the price, and easier to upgrade.
• Desktop Disadvantages: not portable, larger footprint, and require a constant power supply.
• Desktop computers are used for office, business, education, gaming, and general entertainment.

Mobile Computers

• Mobile computers is a group of computers that are more portable than desktop computers.
• Mobile Examples: laptops, tablets, smartphones, and phablets.
• Mobile computers are used for communication, office, business, education, gaming, general entertainment, and device control.
• Mobile examples of communication: make/receive phone calls, Text messaging, Instant messaging, Video calls, Surfing the internet, Sending and receiving emails, and Streaming of music/videos .

Laptop Computers

• Laptop Advantages: lightweight, smaller footprint, low power consumption, low heat generation, and built-in battery.
• Laptop Disadvantages: easier to lose/steal and not always upgradeable.

Tablets

• Tablet Advantages: fast to switch on, lightweight, small footprint, simple touchscreen, built-in battery, low power consumption, and low heat generation.
• Tablet Disadvantages: less storage capacity, easier to lose, slower touchscreen typing, and fewer supported file formats than laptops/desktops.

Smartphones

• Smartphone Advantages: lightweight, small footprint, easy to use on the move, 3G/4G/5G communication, built-in battery, and commonly carried.
• Smartphone Disadvantages: easier to lose, less storage capacity, and slower typing than laptops/desktops.

Phablet

• Phablets are hybrids between tablets and smartphones so tablets that function as smartphones.
• The device size is between a smartphone and a tablet
• Phablets have all the features of a typical smartphone and a tablet.
• Characteristics of computers equal their advantages and disadvantages.