Free On-line Dictionary of Computing:
A term which describes a system that deals
correctly with extended character sets which (unlike ASCII)
use all eight bits of a
. Many programs and
communications systems assume that all characters have codes
in the range 0 to 127. This leaves the top bit of each byte
free for use as a
bit or some kind of flag bit.
These assumptions break down when the program is used in some
non-english-speaking countries with larger alphabets.
If a binary file is transmitted via a communications link
which is not eight-bit clean, it will be corrupted. To combat
this you can encode it with
which uses only
characters. There are some links however which are not even
"seven-bit clean" and cause problems even for uuencoded data.