A common pattern (that my scientific software used) was this: an initial file is created from the raw data pulled from the sequencer.  After sequencing, you could run all sorts of analyses.  Sometimes the analyses themselves, and sometimes intermediate results, where very slow to compute and hence cached in the file.<p>I think it&#x27;s reasonable to be very upset if you have a container file and adding new named chunks to the file has the possibility of causing the old data to become unreadable.  It&#x27;s fair in a crash before the file was saved that new chunks might be bad, but old chunks should be fine.