I'm trying to read IASI GDS Level 1C data (all spectral samples) in the EUMETSAT EPS Native Format, as documented in the Generic Product Format Specification (PDF, 738 KB, 72 pages) and the IASI Level 1 Product Format Specification (PDF, 2.5 MB, 60 pages). EUMETSAT supports a reading routine in IDL.
The IASI Level 1 Product Guide (PDF, 5.8 MB, 110 pages), section 5.1, notes that
The products can be read using standard HDF libraries
but trying to open a test file with
OSError: Unable to open file (Unable to find a valid file signature),
and neither the Generic Product Format Specification nor the IASI Product Format Specification mention HDF, which would be odd if the format was HDF-compatible.