Useful Commands


  • Built-in for retrieving data from standard input and assign the value to a bash variable
  • The command below displays a prompt before the input. Only works for BASH, not for ZSH
read -p "Enter your input here: " variable


Plug and Play

  • Kernel automatically collect information about the IO Device
  • Centrally assign interrupt level & IO Addresses
  • Tell each IO device what its numbers are

IO Operation

  • The process of CPU communicating with the outside world. This can include interactions with humans, other computers, or peripheral devices as shown above. CPU is only involved in initiating the operation and processing the results of the operation!!!