ABSTRACT
The various operating system services that FORTRAN programs require, such as input and output operations, are typically provided by system routines. These fragments of machine code are stored in a system library and must be inserted into the object code for a program before it can be executed. The insertion of library routines is called linkage editing, and is performed on computers running the UNIX™ operating system by a program called the loader (but known to UNIX™ as Id). The result of linking the necessary system routines into the object code for a program is called an executable, and it is only an executable that can be run.
