Binary refers to any system that uses two alternative states, components, conditions or conclusions. It is descended from the Latin word binarius, which means double or pair.
The binary, or base 2, numbering system uses combinations of just two unique numbers, i.e., zero and one, to represent all values. This is in contrast with the decimal system (base 10), which uses combinations of ten unique numbers, i.e., zero through nine, and the hexadecimal system (base 16), which uses combinations of ten unique numbers and the letters a through f.
Virtually all computers are designed to operate internally with all information encoded in binary numbers. This is because it is relatively simple to construct electronic circuits that generate two distinct voltage levels (i.e., off and on or low and high) to represent zero and one. The reason is that transistors and capacitors, which are the fundamental components of processors (the logic units of computers) and memory, have only two states: off and on.
Although the conversion of decimal numbers to binary numbers consumes system resources (in the form of processor time and memory capacity) and greatly increases the length of the numbers (in terms of the number of digits), this is insignificant in comparison to the advantages that it offers for data processing and storage. Humans, in contrast, find long sequences of binary numbers very difficult to read, and thus even highly experienced programmers rarely work directly with them.
A binary file is any file that contains at least some data consisting of sequences of bits that do not represent plain text (i.e., human-readable characters), i.e., data that is not meant to be interpreted through a common character set (such as ASCII). A bit (a contraction of the term binary digit) is the most basic unit of information in computing and communications, and every bit has a value of either zero or one. Binary files include image files, sound files, executable (i.e., runnable) programs and compressed data files.
Binary files are usually the most compact means of storing data (because of data compression), and commands stored in binary form can execute very rapidly, However, it can be difficult to transfer them between differing computer systems, and thus they are sometimes first converted into ASCII form, often using the base64 encoding scheme (as is done with e-mail attachments).
Many systems of binary encoding of data and commands are proprietary (i.e., commercial and secret) and unique to particular hardware and software systems. Thus, there are frequently issues with regard to the portability (i.e., the ability to be used with other hardware and software) and long-term accessibility of data and programs that use such systems.
Although binary formats are now virtually universally used for the processing, exchange and storage of information, the idea of binary systems is not new. In fact, the first known description of a binary numeral system was made by Pingala, a scholar who lived in India more than 2000 years ago. He described the binary numeral system in his book Chhandah-shastra in connection with the short or long syllables in the Veda, ancient religious scriptures that may have predated him by at least two thousand years.
The modern binary number system was first documented by the German philosopher, mathematician and diplomat Gottfried Leibniz in his 1703 publication Explication de l'Arithmétique Binaire. In 1854, the British mathematician George Boole published a landmark paper describing a system of logic that became known as Boolean algebra and which proved fundamental to the use of the binary system in computing. The first binary electronic computer, the Atanasoff Berry Computer (ABC), was constructed from 1939 through 1942 by John Atanasoff, a professor of physics at Iowa State College, with the assistance of his graduate student Clifford Berry.
Although its use for the manipulation and storage of data is relatively recent, the binary system has a longer history of use for the transmission of data. For example, many African tribes sent fairly complex messages with drum beats using combinations of high and low pitches. Morse code, developed by Samuel Morse in 1835 for telegraphic communication, uses a binary system consisting of dots and dashes to represent the letters of the alphabet, numbers and punctuation.
Created June 1, 2005. Updated January 27, 2006.