Merkistökoodauksen

Merkistökoodaus refers to the process of assigning numerical values to characters, enabling computers to store, process, and transmit text. This is crucial for digital communication and data storage as computers fundamentally operate on numbers. Early forms of character encoding, like Baudot code, were developed for telegraphy. The ASCII (American Standard Code for Information Interchange) standard became widely adopted in the mid-20th century, using 7 bits to represent 128 characters, primarily English letters, numbers, and punctuation.

As the need to represent characters from various languages and symbols grew, ASCII proved insufficient. This led to the development of extended ASCII sets and eventually, the Unicode standard. Unicode aims to represent every character in every writing system, as well as symbols and emojis. It assigns a unique code point to each character. However, Unicode itself is a mapping; it does not specify how these code points are stored in bytes.

This is where character encoding schemes like UTF-8, UTF-16, and UTF-32 come into play. UTF-8 is a variable-length encoding that uses 1 to 4 bytes per code point. It is backward-compatible with ASCII, meaning that ASCII characters are represented by a single byte in UTF-8, making it the most popular encoding on the internet. UTF-16 uses 2 or 4 bytes per code point, and UTF-32 uses a fixed 4 bytes per code point. The choice of encoding impacts file size, processing speed, and compatibility with different systems and software.