binary file
binaries
binary data

    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)