Improving Information for Social Policy Decisions -- The Uses of Microsimulation Modeling: Volume II, Technical Papers (1991)
Chapter: Translating TRIM2 Modules to the C Language
Significant work would be required to perform such a port. It would likely take 1 person-year of work, possibly more, by competent software engineers with experience in both MS-DOS and IBM MVS environments. The task is nontrivial; it includes not only code conversion but also conversion of the many procedures currently embodied in the IBM MVS JCL. Validation of the port at the model output level is a complex task important to ensuring that the algorithms in TRIM2, which account for much of its capital content, have been preserved.
Porting TRIM2 to a UNIX Environment
UNIX was originally developed for minicomputer systems and was later adopted for use in scientific workstations. The architectures of these hardware environments have typically been characterized by substantially more real memory and virtual address space than MS-DOS environments as well as by larger disk storage devices and the use of disk server systems linked by high-speed network connections.89
FORTRAN-language translators are available for UNIX-based desktop systems that are at least the equivalent of MS-DOS FORTRAN translators. COBOL-language processors are more scarce, and such a port might require rewriting the current code that manages the CTD, probably in the C language. Such a module could then be called from a FORTRAN subprogram, so that integration of directory functions with the rest of the system could be maintained.
Porting TRIM2 to a UNIX environment would be somewhat easier than porting it to an MS-DOS environment, partly because of the more sophisticated and powerful software development environment and related tools available in typical UNIX environments. The port would still be somewhat lengthy and require software engineers with experience in UNIX and IBM MVS.
Translating TRIM2 Modules to the C Language
Discussion of these ports assumes that the TRIM2 code remains in FORTRAN and that the code would be changed as little as possible during the port. Any change has the potential of introducing problems in that every source of variance between old and new environments threatens the functional equivalence of the new version of the system with the old. Potential small differences in the language processors (compilers) should themselves be viewed with concern,
