binary is the type identifier for a built-in file type which does not have a component type (i.e. an untyped file type). Normally files can only contain values of the same type, which is called the file's component type, however this restriction does not apply to untyped file types. Values of almost any type can be written to and read from untyped file types. Also, because untyped file types do not have component types, there are no buffer variables associated with untyped file types.
For example below is a silly little program that illustrates how to use binary file types.
program silly; var f : binary; begin rewrite(f, 'silly.dat'); write(f, 100, -67.56, false); end.
Operating Systems: All Standard Pascal: No