computing essentials

• Hexadecimal values


  Go from 0 to F. After 9 hexadecimal goes to A,B, C etc
• Computer network


  Two or more computers connected together to allow them to communicate, share folders and share resources e.g. printers

  
• Wireless network advantages


  • New connection points can easily be added without interruption to the network
  • Users can move around freely and still stay connected

  
• Wireless network disadvantages


  • Radio signals can be blocked by walls
  • Each wireless access point (WAP) only has so much bandwidth to share among connected nodes – lots of connections means a slower communication becomes
  • Radio signals can be intercepted by unauthorised users, thus a security risk
• Wired network advantages


  • Increased speed as wired connections have a higher bandwidth
  • More secure as only devices physically connected can see data being transferred

  
• Wired network disadvantages


  • More physical connections needed so more cabling needed
  • More difficult to connect a new device to a network
• Network hardware


  • Network Interface Card (NIC)
  • Hub/Switch
  • Router
  • WAP (Wireless Access Point)
  • Server

  
• Encryption


  The process of scrambling data so that it cannot be understood by anyone but its intended recipient
• Decryption


  The process of unscrambling the data back into its original form. This can only be done if you know the cipher and key used to encrypt it in the first place!

  
• Converting Hex to Denary

  1. Multiply left value by 16

  2. Add on right value
• Converting Denary to Hex

  Divide by 16 and note remainder
• Converting Binary to Hex/Hex to Binary

  Each hexadecimal value represents one nibble of data (a nibble is 4 bits( 1's or 0's)) – therefore split up the hex value into 2 x nibbles
• Binary addition


  Each time you add 2 x bits of data you will output a sum and a carry. Work right to left
• Network


  Multiple devices connected together to enable them to communication or share data

  
• Types of network


  • LAN (Local area network)
  • WAN (Wide area network)
• Bandwidth


  The amount of data that can be transferred at one time
• The structure of the internet
• Key terms


  • Network
  • LAN
  • WAN
  • Hub
  • Switch
  • Router
  • Web server
  • IP address
  • DNS
  • Wireless network
  • Wired network
  • Ethernet cable
  • Fibre optic cable
  • WAP
  • Server
  • Bandwidth
  • Hexadecimal