essentials 1

• Information Technology (IT) system


  Concerns the processing, storage and/or transfer of information
• Forms of information


  • Words
  • Numbers
  • Pictures
  • Sounds
  • Videos
• IT System


  Consists of computers, the telecommunications network and other programmable electronic devices
• IT is often seen as a very daunting subject because it involves many different specialist areas
• Basic principle of IT

  To simply help us to improve the way we deal with information in all areas of our lives
• Areas where IT is used

  • Business
  • Industry
  • Government
  • Education
  • Health care
  • Everyday home/social life
• Computers enable us to process information and perform specific tasks much more quickly than we often do ourselves
• IT Systems are usually very flexible and can be made to perform a wide range of different tasks
• IT networks allow us to distribute and share information very quickly
• Information Society


  The effective use of information is regarded as the defining element of the 20th – 21st centuries
• Computer


  An electronic device that uses set of instructions to perform tasks based on the given input to produce output
• Computer System


  A group of related components and operations that interact to perform tasks to achieve a common goal
• Parts of a computer System

  • Input
  • Processing
  • Output
  • Storage
• Components of a computer System

  • Hardware
  • Software
  • Data/Information
  • Procedures
  • People
  • Communications
• Hardware


  Physical components of a computer that we can touch
• Software


  Programs that control the computer and make it function
• Data


  Raw materials that need to be processed
• Information


  Manipulated or processed data
• Procedures


  Description of how things are done in step by step to accomplish result/results
• Communications


  When one computer system is setup to share data and information electronically with another computer system
• Mainframe


  • Large and powerful computer that is capable of serving a vast number of users at the same time
  • Users do not sit down in front of the mainframe itself, they connect to it using another smaller computer (or dumb terminal)
  • Mainframes need to process and store data and information, for many different users, therefore they require much more processing powers and storage capacity than other computers and hence can be very expensive
• Minicomputer


  • Smaller, less powerful version of a mainframe
  • Often cheaper due to its lower processing power and storage capacity (as compared to a mainframe)
  • Not able to serve as many users at once
  • Users do not sit down in front of the minicomputer itself, they connect to it using a smaller computer or a dumb terminal
  • Often used by small and medium sized companies or by departments in very large organizations (to provide a centralized storage of information and computer programs)
• Personal Computer (PC)


  • A computer (most mostly used in homes/offices)
  • Consists of a system unit housing CPU (central processing unit), disk drives, a Video Display Unit (VDU), a keyboard and a mouse mounted in a motherboard
  • Can be used for thousands of different tasks from creating a simple document to controlling a large industrial machine
• Network Computer (NC)


  • A low-cost version of the PC
  • Designed to connect to and be managed by a central computer (i.e. a mainframe or minicomputer)
  • Every time the Network Computer is switched on (booted), it retrieves the latest version of the software it needs from the central computer
  • Tend to have slightly less processing power and storage capacity than PCs and are substantially less expensive
  • Cannot be used if it is not connected to the central computer
  • Tend to be used in call centers, help desk, and data processing departments where users do not require the flexibilities of a PC – but instead need to access central software and information
  • One main advantage is that when software requires an upgrade, only the central computer is updated instead of having to update each individual machine
• Portable Computers


  • Can be carried around easily and use a Liquid Crystal Display (LED) and a special re-chargeable battery
  • Laptops are similar to personal computers, except that they comprise an integrated unit with the screen in the lid and keyboard built into the base
  • Palmtops (also known as Personal Digital Assistants (PDAs)) do not have quite the same features and components as PCs, they are used mostly as personal organizers
  • Tablets are mobile computers which use a touchscreen (which can be activated by a fingertip) or a screen which allows the use of a stylus or digital pen, often used by delivery people or warehouse stock-takers
• Categories of Computer Hardware

  • Input Devices
  • Central Processing Unit (processing device)
  • Memory (Primary Storage)
  • Storage Devices (secondary storage)
  • Output Devices
  • Communication Hardware
• Input Devices


  • Used to feed commands and data into the computer
  • Examples: Keyboard, Mouse, Scanner, Webcam, Microphone
• Keyboard


  Used to enter data into a computer, can enter commands, select menu options and enter data/values
• Global Positioning Systems


  Multimedia PDAs
• Tablets


  • Mobile computers which, instead of using a keyboard or mouse, use a touchscreen (which can be activated by a fingertip) or a screen which allows the use of a stylus or digital pen
  • Often used by delivery people or warehouse stock-takers who would find even a laptop too heavy for their work
  • Can be used to store files, access emails and to surf internet
• Elements of a computer

  • Hardware
  • Software
• Categories of computer hardware

  • Input devices
  • Central Processing Unit (processing device)
  • Memory (Primary Storage)
  • Storage Devices (secondary storage)
  • Output Devices
  • Communication Hardware
• Input devices


  Used to feed commands and data into the computer
• Central Processing Unit (CPU)


  • The brain of the computer
  • Housed inside the system unit
  • Interprets and carries out instructions to manipulate the data into information
  • Has an internal clock that is oscillating at a defined speed, providing a heartbeat for the processor's work
• Components of a CPU


  • Control Unit
  • Arithmetic Logic Unit
  • Registers
• Cache


  Immediate access memory incorporated as a buffer to maintain a constant flow of the data to and from the CPU
• ROM (Read Only Memory)


  • Special type of memory that is permanent, contains all the information the computer needs to switch itself on, check that all its systems are working well and to tell the PC what things are plugged on it
  • Cannot be changed or written by the user
  • Non-volatile, keeps the data even if the computer is switched off
• RAM (Random Access Memory)

  • Used in a PC to temporarily store the data when an application is running
  • Also used to store program instructions and feed information to the CPU to process it
  • Not permanent, contents are lost when the PC is switched off
• Uses of RAM


  • Main memory
  • Cache
• Main Memory


  • Largest amount of RAM installed on the motherboard of the PC
  • Used to run software applications and temporarily store data that is entered by the user