23 system clock is a clock in a computer that shows the time date and http://support.esri.com/knowledgebase/techarticles/ShowImage.asp?ImageId=24622&ImageType=JPG

21Read Only Memory (Rom) is a content that only can be read but cant be changed

20.Radom Access Memory (Ram) is the memory of the computer that is used by programs to do tasks when the computer is on.

19.pointer is a arrow to show you the a certain direction

18.plotter is a devise run by the computer this device is used to draw picture or plot graphs

17.output devises are computers hardware that gives out information.

16.optical storage devises is a term that refers to storage data