Write short. notes on ASCII, Unicode and Parity bit.

Subject Introduction to Computer System
NU Year Set: 2.(c) Marks: 5 Year: 2010

ASCII Code

ASCII, stands for American Standard Code for Information Interchange. It's a 7-bit character code where every single bit represents a unique character. On this webpage you will find 8 bits, 256 characters, ASCII table according to Windows-1252 (code page 1252) which is a superset of ISO 8859-1 in terms of printable characters. In the range 128 to 159 (hex 80 to 9F), ISO/IEC 8859-1 has invisible control characters, while Windows-1252 has writable characters. Windows-1252 is probably the most-used 8-bit character encoding in the world.

Unicode

The Unicode Standard provides a unique number for every character, no matter what platform, device, application or language. It has been adopted by all modern software providers and now allows data to be transported through many different platforms, devices and applications without corruption. Support of Unicode forms the foundation for the representation of languages and symbols in all major operating systems, search engines, browsers, laptops, and smart phones—plus the Internet and World Wide Web (URLs, HTML, XML, CSS, JSON, etc.). Supporting Unicode is the best way to implement ISO/IEC 10646.

The emergence of the Unicode Standard and the availability of tools supporting it are among the most significant recent global software technology trends.

Parity Bit

A parity bit, also known as a check bit, is a single bit that can be appended to a binary string. It is set to either 1 or 0 to make the total number of 1-bits either even ("even parity") or odd ("odd parity").

The purpose of a parity bit is to provide a simple way to check for errors later. When data is stored or transferred electronically, it's not uncommon for bits to "flip" — change from a 1 to a 0, or vice versa. Parity checks can help detect some of these errors. For example, to check a binary sequence that has even parity, the total number of ones can be counted. If the number of ones is not even, an error is likely to have occurred.

 

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