The Computer System

• A computer system is composed of three (3) main components: the Hardware, the Software, and the Liveware
• Hardware


  The physical parts that play an integral role in computer systems
• Hardware components

  • Motherboard
  • Input and output devices (such as keyboard, mouse)
  • CPU
  • Storage devices
• Software

  Programs and applications installed in your computer
• Software components

  • System Software
  • Application Software
• System Software

  Low-level programs that runs in the background by the operating system at a fundamental degree
• Application Software


  Software created or written to perform a variety of specific tasks for the user
• Application Software examples

  • Microsoft Office (Word, Excel, PowerPoint)
  • Browsers (Google Chrome, Mozilla Firefox)
  • Media Player
  • Auto CAD
• Liveware

  Computer users who instruct the PC to execute on guidelines
• A Computer System Structure consists of connected devices to a brain device that gives entry to memory sharing
• Main hardware components of a computer system

  • Input Devices
  • Output Devices
  • Processing Devices
  • Storage Devices
  • Communication Devices
• Input Devices


  Devices used for entering data in the computer
• Output Devices


  Devices that put out the information or data to the user or to another device
• Output Devices examples

  • Monitor
  • Speakers
  • Headphones
  • Printer
• Processing Devices

  Core parts of the computer assigned to process data
• Processing Devices examples

  • Central Processing Unit (CPU)
  • Graphics Processing Unit (GPU)
• Storage Devices

  • Primary Storage Devices
  • Secondary Storage Devices
• Primary Storage Devices

  Smaller in size and have the fastest data speed, e.g. Random Access Memory (RAM)
• Secondary Storage Devices

  Bigger in size but has slow data speed, e.g. Hard Disk Drive, Optical Disk Drive, USB Flash Disks/Drives
• Communication Devices

  Hardware devices assigned to transmit analog or digital signals/messages, can be wireless or hardwired
• Central Processing Unit (CPU)


  The electronic circuitry within a computer that executes instructions that make up a computer program
• The CPU performs basic arithmetic, logic, controlling, and input/output (I/O) operations specified by the instructions in the program
• There are two types of booting: Warm Booting and Cold Booting
• Warm Booting

  The process of restarting a computer that is already powered on
• Cold Booting


  The process of turning on a computer after it had been powered off completely
• Bootloader


  A special operating system software that loads into the working memory of a computer after start-up
• The boot sequence is the order in which a computer searches for nonvolatile data storage devices containing program code to load the operating system
• The power-on self-test (POST) is the initial diagnostic test performed by a computer when it is switched on, before the boot sequence begins
• Traps and Interrupts are events that breaks a normal sequence of orders or instructions that is being process or executed by the CPU
• Traps


  Synchronous interrupts sensed by the CPU as an abnormal condition that means an error has happened
• Interrupts


  Asynchronous signals made by the hardware (devices like graphics card, I/O ports, hard disk, etc.)
• When an interrupt is already being executed, other interrupts are disabled for the first interrupt to be done
• Device Drivers


  Software components that can be augmented into an OS to handle a specific device
• The operating system manages from device drivers to handle all I/O devices
• Tasks of a device driver

  • Manage requests from the device independent software
  • Execute required error handling and interact to give and take I/O with the device controller
  • See to it that all processes are completed and the request is executed successfully
• I/O Operation

  1. Device driver loads the registers within the device controller

  2. Device controller examines the files and processes the registers to determine the appropriate tasks or action to execute

  3. Controller begins to manage the transfer of data from the device to its local buffer

  4. Device controller signals the device driver via interrupt that has finished its task

  5. Device driver returns control to the operating system
• Synchronous I/O

  CPU process waits while I/O proceed
• Device driver tasks

  1. Manage requests from the device independent software by accepting the appropriate tasks

  2. Execute required error handling and interact to give and take I/O with the device controller

  3. See to it that all processes are completed and the request is executed successfully
• I/O Operation

  1. Start by loading the registers within the device controller

  2. The device controller examines the files and processes the registers to determine the appropriate tasks or action to execute

  3. The controller begins to manage the transfer of data from the device to its local buffer

  4. Once the transfer of data has been successfully completed, the device controller signals the device driver via interrupt that has finished its task

  5. Then the device driver returns control to the operating system
• Synchronous I/O

  CPU process waits while I/O proceeds