Writing System - Writing Systems On Computers

Writing Systems On Computers

In computers and telecommunication systems, writing systems are generally not codified as such, but graphemes and other grapheme-like units that are required for text processing are represented by "characters" that typically manifest in encoded form. There are many different character encoding standards and related technologies, such as ISO/IEC 8859-1 (a character repertoire and encoding scheme oriented toward the Latin script), CJK (Chinese, Japanese, Korean) and bi-directional text. Today, many such standards are re-defined in a collective standard, the ISO/IEC 10646 "Universal Character Set", and a parallel, closely related expanded work, The Unicode Standard. Both are generally encompassed by the term Unicode. In Unicode, each character, in every language's writing system, is (simplifying slightly) given a unique identification number, known as its code point. Computer operating systems use code points to look up characters in the font file, so the characters can be displayed on the page or screen.

A keyboard is the device most commonly used for writing via computer. Each key is associated with a standard code which the keyboard sends to the computer when it is pressed. By using a combination of alphabetic keys with modifier keys such as Ctrl, Alt, Shift and AltGr, various character codes are generated and sent to the CPU. The operating system intercepts and converts those signals to the appropriate characters based on the keyboard layout and input method, and then delivers those converted codes and characters to the running application software, which in turn looks up the appropriate glyph in the currently used font file, and requests the operating system to draw these on the screen.