Computer systems typically comprise a combination of computer programs and hardware, such as semiconductors, transistors, chips, circuit boards, storage devices, and processors. The computer programs are stored in the storage devices and are executed by the processors. Fundamentally, computer systems are used for the storage, manipulation, and analysis of data.
One type of data is character data. A character is a unit of information, a grapheme, or a symbol that represents or controls data. Characters have a physical appearance, called a glyph, when displayed on a display device or printed via a printer. Examples of characters include letters, numerals, and punctuation marks. Characters may also include control characters, which describe the formatting of other characters. Examples of control characters include carriage return and tab.
Characters are often encoded or represented in a computer system as numbers, which are typically stored in memory as a byte (8 bits), two bytes (16 bits), or a variable number of bytes. These numbers are called code points. Many mappings of characters to code points exist, which are called coded character sets. Examples of coded character sets include the American Standard Code for Information Interchange (ASCII), the Extended Binary Coded Decimal Interchange Code (EBCDIC), the 16-bit Unicode Transformation Format (UTF-16), and the International Organization for Standardization (ISO) 8859-1.