State of information which exists as discrete units of (typically) numeric code, such as that which is the only type of information a computer can process. In computers, digital data is a binary system, or some combination of 1s and 0s, the only two digits a computer can identify. The "opposite" of digital data is analog data, in which information exists as a continuous signal. See Digital and Analog. Analog data can be converted to digital data, and vice versa, by means of an analog-to-digital converter and a digital to analog converter, respectively. A somewhat common example of digital data is DNA itself, or the genetic material comprising all life on Earth. In that case, the digital data is a quaternary system, or made up of four "digits," A, C, T, G—or adenine, cytosine, thymine, and guanine—which are the four bases which comprise the basis of the DNA molecule. Combinations of these four digits are what make up all life, at least on Earth.