ROM (Read-Only Memory)
ROM's are memory chips that store data that is prerecorded. Data written on a ROM chip cannot be removed, only read. Often in personal computers you can find ROM chips on the motherboard but also in other electronic devices such as calculators and laser printers. In personal computers ROM often contains vital information like the program to start up the computer.
ROM won't loose it's data when you turn off the computer, withholding electricity. It is a type of non-volatile memory (memory that still holds the data when the electricity cuts off) and is permanent.