Generalized computational subroutines can reduce programing repetitions and wasteful computer storage use. The most useful are those that are flexible enough to handle a wide variety of situations. Subroutines may have details open to change in order to blend into the main program. They may be built into the computer library or supplied by the programer as part of this program deck. Library subroutines have limiting specifications and ranges, entry and exit commands and addresses which should be designed to fit into any program. Operating routines, the most prominant type of which are the input-output sets or "packages," differ from other subroutines in that they partially control the computer and return control to the main program when their work is completed. Basic subroutines of particular value in a chemical library include basic arithmetic computations, function evaluations, numerical analyses plus collating and sorting programs. Service routines--compilers, assemblers, debugging and machine testing programs--are also useful. (KB)