binary file
n : (computer science) a computer file containing
machine-readable information that must be read by an
application; characters use all 8 bits of each byte
Source: The Free On-line Dictionary of Computing (27 SEP 03)
binary file
A file containing binary data,
i.e. arbitrary bytes or words, as opposed to a text file
containing only printable characters (e.g. ASCII characters
with codes 10, 13, and 32-126).
On modern operating systems a text file is simply a binary
file that happens to contain only printable characters, but
some older systems distinguish the two file types, requiring
programs to handle them differently.
A common class of binary files is programs in machinelanguage ("executable files") ready to load into memory and
execute. Binary files may also be used to store data output
by a program, and intended to be read by that or another
program but not by humans. Binary files are more efficient
for this purpose because the data (e.g. numerical data) does
not need to be converted between the binary form used by the
CPU and a printable (ASCII) representation. The
disadvantage is that it is usually necessary to write special
purpose programs to manipulate such files since most general
purpose utilities operate on text files. There is also a
problem sharing binary numerical data between processors with
different endianness.
Some communications protocols handle only text files,
e.g. most electronic mail systems before MIME became
widespread in about 1995. The FTP utility must be put into
"binary" mode in order to copy a binary file since in its
default "ascii" mode translates between the different text
line terminator characters used on the sending and receiving
computers.
Confusingly, some files produced by wordprocessors, and
rich text files, are actually binary files because they
contain non-printable characters and require special programs
to view, edit, and print them.
(2002-01-19)
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