Hakon’s design is great. This has been adopted by big AMR codes such as Chombo due to the performance issues mentioned by Hakon. Note that when reading in parallel, all ranks will need to have access to the AMRBox datasets to figure out offsets into the image data arrays. We should make sure that some sort of collective operation is done (either ourselves in the reader via MPI or using the HDF5 parallel capabilities) to avoid performance issues.