What is the difference between ROM and RAM?

Question

What is the difference between ROM and RAM?

Answer

There is one major difference between a ROM chip and a RAM chip.

A ROM chip does not require a constant source of power to retain the information stored on it, whereas a RAM chip does require a constant source of power to retain the information. When a computer is turned on, and programs are being run, the programs information is stored in the RAM chip for better efficiency and speed. However, as soon as the computer is turned off any information stored in the RAM chip is lost. With a ROM chip, any information stored on the chip remains on it with or without power.

ROM chips are commonly used in gaming system cartridges, like the original Nintendo, Gameboy, Sega Genesis, and a number of others. The game cartridge stores the game programming on a ROM chip which is read by the game console when the cartridge is inserted into the console.

ROM chips can also be found in computers, to store the programming needed to begin the initial boot up process when turning on a computer. Using non-volatile storage is the only way to begin the start up process for computers and other devices that use similar a start up process. The most common type of programmable ROM (PROM) chip in a computer is the BIOS.

RAM chips are also used in computers, as well as other devices, to store information of the programs currently running on the computer. However, only volatile information can be stored on RAM chips, due to that fact that if power is lost to the computer all information stored in the RAM is lost.

The oldest ROM-type storage media can be dated back to 1932 with drum memory. Today, ROM-type storage media is still used and continues to be improved upon for better performance and storage capacity.