• Input devices – put data into the processor e.g scanner, keyboard, mouse
• output devices – display data from the processor e.g. monitor, printer, projector,
• Processor type – dual, triple and quad code 
  • speed (Hz) – 1.8GHz to 3.4Ghz (faster)
• Random Access Memory – used for current files, temporary storage of data which is lost if the device is switched off.
• Read Only Memory – ROM retains its memory even after the computer is turned off.

Device types

• Supercomputer – large processing power and memory, used by large organisations.
• Desktop – processing power but not portable.
• laptop – portable but generally less powerful than a desk top
• tablet – portable but no physical keyboard.
• smartphone – use 3G or connect to wifi. same functions as a tablet.