4 File Structure and Performance
This chapter describes the file structure of a netCDF classic or
64-bit offset dataset in enough detail to aid in understanding netCDF
performance issues.
NetCDF is a data abstraction for array-oriented data access and a
software library that provides a concrete implementation of the
interfaces that support that abstraction. The implementation provides
a machine-independent format for representing arrays. Although the
netCDF file format is hidden below the interfaces, some understanding
of the current implementation and associated file structure may help
to make clear why some netCDF operations are more expensive than
others.
For a detailed description of the netCDF format, see File Structure and Performance. Knowledge of the format is not needed for reading
and writing netCDF data or understanding most efficiency
issues. Programs that use only the documented interfaces and that make
no assumptions about the format will continue to work even if the
netCDF format is changed in the future, because any such change will
be made below the documented interfaces and will support earlier
versions of the netCDF file format.
