How have the tools changed between different CDs in the series?
The IDL tools used for SSM/I data can also read and display SMMR data. See /TOOLS/IDL/README.IDL for details. The freeform and makeHDF tools are not included on SMMR CDs, or on SSM/I CDs after North Volume 78.0, South Volume 37.0, and Global Volume 158.0. Users who want copies of these utilities should contact NSIDC User Services. The original GETBENCH.CSH script included with SSM/I EASE-Grid CD-ROMs will not work correctly for SMMR time files; therefore, it has been replaced by GET_EASE_DATA.CSH, a script that works for both SMMR and SSM/I files.