Opened "4_vds.h5" with sec2 driver.
vds_dset                 Dataset {9/Inf, 4/4, 4/4}
    Location:  1:800
    Links:     1
    Maps:      {1} Source {
                      4_%b.h5   /source_dset
               }
    Storage:   576 logical bytes, 0 allocated bytes
    Type:      32-bit little-endian integer
