Binary vs. ASCII Files

[Keefe]

Here is something that i found while doing some research on ASCII.  It might be of some use...

At heart all files are binary files -- that is, a collection of 1s and 0s. But there's a subset of binary files we call ASCII, or plain text files. ASCII is short for American Standard Code for Information Interchange.


An ASCII file contains plain text. Each byte in an ASCII file represents a single character according to the ASCII code.

Ignoring that last bit

ASCII text uses only the first seven bits of an eight-bit byte to represent a character. Using seven bits gives you 128 choices, more than enough for the alphabet, numbers, and common punctuation. The eighth bit in each byte is ignored. In binary files, though, every bit counts.


So that's the chief difference between ASCII files and binary files: In ASCII files each byte represents exactly one character, and you can ignore the eighth bit of each byte. All computer programs, and most non-text data formats are stored in binary format, in which all eight bits in each byte are significant. Even word processor files are stored as binary files, because they contain formatting information in addition to the text.


Lately extended character sets have started using all eight bits to add symbolic and graphic characters, but there's no accepted standard for how these characters are mapped. ASCII has been replaced in many applications by UniCode, which uses 16 bits per character to represent non-Roman alphabets like Japanese, Chinese, and Cyrillic.