High Quality Content by WIKIPEDIA articles! The CERN Program Library or CERNLIB is a collection of FORTRAN77 libraries and modules, maintained "as is" by CERN. Its content ranges from more specialized data analysis of high energy physics to general purpose numerical analysis. Lower-level parts of the CERN Program Library are most prominently used by the data analysis software PAW and the detector simulation framework GEANT (which themselves are contained in the CERN Program Library).