The very first entry in an UIO file is always the
fileform uio entry,
containing information about the file format and conversion type.
Afterwards, entries can follow in any order.
But it is perhaps a good idea to start the file with three special entries
history) as in
A recommended format for sets of multi-dimensional arrays (e.g. hydrodynamics: x-axis, y-axis, z-axis, density, velocities, energy, ...) is shown in Sect. 5.1.