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.
By contrast, read-only memory (ROM) stores data by permanently enabling or disabling selected transistors, such that the memory cannot be altered. Writeable variants of ROM (such as EEPROM and flash memory) share properties of both ROM and RAM, enabling data to persist without power and to be updated without requiring special equipment.