and variable memory. Applications written in BASIC could thus be far larger than the size of working memory, via a set of cooperating programs that CHAIN back and forth amongst themselves as program flow moves within the overall application. Chain loading in FORTRAN programs Many versions of Fortran include a CALL CHAIN or CALL LINK statement that performs chain loading, preserving the contents of COMMON storage. This is not the same as the unrelated LINK subroutine in GNU Fortran. Chain loading in OS/360 OS/360 and successors use the XCTL (for "transfer control") macro for chain loading. Because of the operating system's memory management this may or may not result in replacement of the code of the calling program in memory. See also CHAIN (CONFIG.SYS directive) (chain executing multiple CONFIG.SYS files in DR-DOS) References Operating system technology Process (computing)