In my program, I use the HDF_SD_GETDATA to retrive the data from MODIS L1B image. The program runs successfully in IDL 6.3, but in IDL 7.0, The error message is 'HDF_SD_GETDATA: Unable to read the specified HDF-SD slice'  when I read NASA's MODIS L1B (  file name for example: MOD021km.A2008345.0355.005.2008345221404.hdf) image. Would ypu mind to tell me whether are  there function/precedu  in IDL 7.0 to get the MODIS L1B data.