binary file
<file format> Any file format for digital data that does not consist of a
sequence of printable characters (text). The term is often used for executable
machine code.
All digital data, including characters, is actually binary data (unless it uses
some (rare) system with more than two discrete levels) but the distinction
between binary and text is well established. 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 machine language ("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 newline characters used on the sending and
receiving computers.
Confusingly, some word processor files, and rich text files, are actually binary
files because they contain non-printable characters and require special programs
to view, edit and print them.
(2005-02-21)
Nearby terms:
binary counter « binary data « binary exponential
backoff «
binary file » binary large object » binary
package » binary search
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