ICT (Types and componenets of a computer system)

• Hardware


  The electronic, physical components that make up a typical computer system. These may include input and output devices as well.
• 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)
• External Hardware Devices


  • Monitor
  • Keyboard
  • Mouse
  • Printer
  • External Storage Devices
• Software


  The techniques, methods, commands, and instructions tell the device what to do and how to do it. They are the programs that control the computer system and process data.
• Software


  Relates to ideas & instructions for using physical objects.
• Types of software


  • Application software
  • System 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).
• Examples of Application software


  • Spreadsheets
  • Databases
  • Word processors
• System Software


  The software is designed to provide a platform all other software can run.
• Examples of System Software


  • Compilers
  • Linkers
  • Device drivers
  • Utilities
  • Operating systems
• Compilers


  The software translates the High-level language into Machine code (Language Processor).
• Linkers


  A Software that creates the links between Language processors into workable solutions (Data definition language).
• 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, Scan Disk, Disk Defragmentation, etc.)
• 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.
• Analogue data


  Data in the real world that forms smooth curves, not limited to two specific values.
• Digital data


  Data that computers can only understand in the form of binary digits (0,1), changing in discrete steps.
• Converting analogue to digital data


  1. Analogue to digital converter (ADC)

  2. Digital to analogue converter (DAC)
• Central Processing Unit (CPU)


  The component of the computer that understands and executes hardware and software operations. It consists of a control unit (CU), an arithmetic and logic unit (ALU), and tiny memory regions known as registers.
• Random access memory (RAM)


  Temporary memory storage, lost after power is shut down, performs read and write functions, is used to store data that are currently in use, and can be increased in size to improve operational speed.
• Read-only memory (ROM)


  Permanent memory storage, non-volatile, can only be read from, used to store computer's configuration data, such as BIOS.
• BIOS


  Stores the date, time and system configuration on a non-volatile chip called a CMOS (complementary metal oxide semiconductor) – this is usually battery powered.
• RAM vs ROM


  RAM is temporary and volatile, ROM is permanent and non-volatile
• RAM vs ROM


  RAM can be written to and from, but ROM can only be read from
• RAM vs ROM


  RAM is used to store data, files, programs, and parts of OS that are currently in use, ROM is used in storing start-up data
• Input devices


  Hardware that enables data entry
• Output devices


  Hardware that displays the result or solution of the input after it has been processed
• Input devices vs Output devices

  Input devices can only send data, Output devices can only receive data
• Input devices vs Output devices

  Input devices are necessary for a computer to receive commands from the user, Output devices are needed to display the outcome of the processing
• Input devices vs Output devices

  Input devices are complex, Output devices are simpler
• Backing/Secondary storage


  Required to store significant amounts of data permanently, most commonly in the form of Hard disk drives and Solid-state drives
• Internal memory vs Backing storage


  RAM contents are lost when power is lost, ROM is read-only, and backing storage is permanent even without power
• Internal memory vs Backing storage


  RAM and ROM are much smaller than backing storage
• Internal memory vs Backing storage


  RAM and ROM are significantly faster in accessing data than backing storage
• Internal memory vs Backing storage


  Backing storage is much cheaper than internal memory
• Internal memory vs Backing storage


  Internal memories are fixed, and backing storage can be fixed or portable
• Internal memory vs Backing storage


  Internal memories can be directly read by the CPU, while backing storage needs to be moved into the RAM before being read by the CPU
• Operating systems


  Controls operation of input, output & backing storage, Supervises loading, running & storage of application programs, Deals with errors in application programs, Maintains security of the whole computer system, Maintains a computer log
• User interfaces offered by operating systems


  • Command line interface
  • Graphical user interface
  • Dialogue-based user interface
  • Gesture-based user interface
• Command line interface


  User needs to type in commands to communicate with the computer, not restricted to pre-defined options, possible to alter computer configuration settings, needs to learn many commands for basic operations, all commands need to be typed in, which is time-consuming, very error prone