The oral mucosa in the area of crenation is usually of normal color, but there may be erythema (redness) if exposed to a high degree of friction or pressure. Crenated tongue is usually asymptomatic and harmless.
ROM stands for read-only memory. It's used to store the start-up instructions for a computer, also known as the firmware. Most modern computers use flash-based ROM. It is part of the BIOS chip, which is located on the motherboard.
There is one major difference between a ROM and a RAM chip. A ROM chip is non-volatile storage and does not require a constant source of power to retain information stored on it. When power is lost or turned off, a ROM chip will keep the information stored on it.