Huh! Good to know. ftp:&#x2F;&#x2F;root.cern.ch&#x2F;root&#x2F;doc&#x2F;11InputOutput.pdf[1] The spec for anyone interested. 
 For comparison:<a href="https:&#x2F;&#x2F;www.hdfgroup.org&#x2F;projects&#x2F;hdf5_aip&#x2F;aip15.gif" rel="nofollow">https:&#x2F;&#x2F;www.hdfgroup.org&#x2F;projects&#x2F;hdf5_aip&#x2F;aip15.gif</a> to page 6 on CERN&#x27;s PDF.