Opened "5_vds.h5" with sec2 driver.
vds_dset                 Dataset {9/Inf, 4/4, 4/4}
    Location:  1:800
    Links:     1
    Maps:      {3} Source {
                      5_a.h5   /source_dset
                      5_b.h5   /source_dset
                      5_c.h5   /source_dset
               }
    Storage:   576 logical bytes, 0 allocated bytes
    Type:      32-bit little-endian integer
