Author: Jayesh Krishna; Danqing Wu; Jim Edwards; Ed Hartnett; John M. Dennis; Mariana Vertenstein

The SCORPIO (Software for Caching Output and Reads for Parallel I/O) library was developed to improve the ability of component models of the Energy Exascale Earth System Model (E3SM) to perform I/O efficiently by leveraging other low-level I/O libraries. The SCORPIO library was derived from the Parallel I/O library (PIO) that has been developed over several years to improve the ability of component models of the Community Earth System Model (CESM) and Energy Exascale Earth System Model (E3SM) to perform I/O. The interface is sufficiently general to be useful to a broader spectrum of applications. The focus of development has been on backend tools that use the NetCDF file format. SCORPIO currently supports NetCDF, PnetCDF and ADIOS as the backend libraries.

SCORPIO supports the interfaces supported by the PIO library and includes C and F90 APIs compatible with the PIO library. The library also includes improvements in user data caching and aggregation algorithms that significantly improve performance. A new decomposition strategy has been introduced which gives the user more ability to tune I/O communications.

This user's guide provides information on how to use the SCORPIO library and an overview of the internal algorithms used by the library.

Please review the ChangeLog that is included with the distribution for up-to-date release information.