types and components of computer systems

• Some devices, like touchscreens, can function as both input and output devices.
• Output devices display or present the results of processing, like monitors and printers.
• RAM (Random Access Memory) stores data that can be accessed quickly by the processor.
• ROM (Read Only Memory) contains permanent information such as BIOS settings.
• CPU stands for Central Processing Unit.
• The CPU is responsible for controlling all other hardware components within the computer system.
• Input devices are used to provide data and control signals to a computer, such as keyboards and mice.
• Two types of software:

  • Application software:
  • Provides services that allow the user to do specific tasks.
  • It can be general-purpose software or custom-made software. (Specialist software)
  • E.g., Spreadsheets, databases, and word processors.
• System Software


  The software is designed to provide a platform all other software can run
• Compilers

  The software converts the program written by a human in high level language into binary code
• Linkers


  A Software that takes files produced by the compiler and combines it into a program the microprocessor can execute
• Device drivers


  A software that enables the device to work with another, externally connected device
• Utilities


  A system software that provides the necessary facilities (Antivirus)
• Operating systems


  To enable computer systems to function and allow users to communicate with computer systems, special software, known as operating systems (OS), have been developed
• Computers can only understand data in the form of binary digits (0,1); this is commonly known as digital data. 
• Computers process real world data into digital form using ADC (analogue to digital converter), and its output is given back in analogue form using DAC (digital to analogue converter).
• CPU

  • Contains a control unit (CU) that directs the operations of the processor, sends control signals to other components of the system and input and output devices
  • Contains an arithmetic and logic unit (ALU) that performs arithmetical and logical operations (addition, subtraction etc)
  • Contains memory storage locations within the CPU, known as registers
• Clock


  A quartz crystal that sends pulses to control the rate the CPU processes instructions
• • Internal Hardware Devices:
  • Central processing unit
  • Processor
  • Motherboard
  • Internal memory consisting of RAM & ROM
  • Graphics & Sound Cards
  • Internal Storage devices like Hard disk drives (HDD) and solid-state drives (SSD)
  • Network interface card (NIC)
• graphics card: printed circuit board that controls the output of the images we see on the computer monitor
• • External Hardware Devices:
  • Monitor
  • Keyboard
  • Mouse
  • Printer
  • External Storage Devices
• software: programs or applications that give instructions to the computer to carry out tasks
• Sound card: printed circuit board that controls output to speakers and headphones.
• main memory/internal memory: stores all the data and instructions being used
• Examples of applications software: word processing, spreadsheet, database, presentation, graphics, and video editing
• System Software: includes operating system, device drivers, utilities, and other essential software
• Operating System (OS): manages hardware resources and provides an interface between user and computer
• 1. RAM is a temporary memory device, whereas ROM is a permanent one.
  2. RAM is volatile, ROM is non-volatile.
  3. RAM can be written to and from, but ROM can only be read from.
  4. RAM is used to store data, files, programs, and parts of OS that are currently in use. However, ROM is used in storing start-up data,
• actuator: a device that causes a machine or other device to operate
• transistor: a device that regulates current or voltage flow and acts as a switch for electronic signals
• input device: any hardware device that sends data to a computer.

  output device: any device used to send data from a computer to another device or user
• backing storage devices: secondary storage device that is non volatile, and can be internal or external. ex: hard drive, solid state drive, memory cards, CDs or DVDs
• operating system: set of programs that control the software and hardware of a computer
• volatile: data is permanently lost when power is switched off
• non-volatile: data is retained when power is switched off
• BIOS: Basic Input/Output System. It is a set of instructions that control the basic operations of the computer.
• peripherals: external devices that provide input and output for the computer. ex: keyboard, mouse, printer
• Examples of operating systems: Windows, macOS, Unix
• User Interfaces:

  Command line interface (CLI): A text based interface that allows the user to interact with computer using keyboard input at a prompt on the screen.
• Graphical user interface/WIMP interface (GUI) - A graphical user interface uses icons and graphics to display and interact with a computer's user interface by clicking on the icons. It uses windows, icons, menus and pointers to interact with users.