optical storage writes and retrieves data using a laser or similar. Magnetic storage uses a coating on a disc or tape to hold data, by manuplating the tiny ferrous elements on the surface it can...
RAM and ROM
RAM - random access memory - short term memory for the system
ROM - read only memory - long term storage for files, etc (your hard drive, flash drive, cd, dvd, etc.)
Ill be nice and list a few examples. Your hard drive. a CD or DVD or Blu-Ray disk a USB stick (aka thumb drive) your iPod (what do u mean u dont have one!?) RAM (it is a volatile storage device)...