ROM is an acronym of a computer's read-only memory. On ROM, data is prerecorded for read only which can not be removed. ROM is nonvolatile and it retains its contents regardless of whether the computer is on or off. Most personal computers contain a small amount of ROM that stores critical programs such as the program that boots the computer. In addition, ROMs are used in calculators and peripheral devices such as laser printers, whose fonts are often stored in ROMs.