RFC-9: Comment 3

Comment authors

This comment was written by: Chris Barnes, German BioImaging

Conflicts of interest (optional)

None

Summary

I have implemented a simple rust-based CLI tool for writing a filesystem OME-Zarr hierarchy into a .ozx.

Minor comments and questions

Use case documentation

The limitations of the ZIP format are presented well in the RFC; it will be important for the eventual spec changes to make clear the use cases for which .ozx is and is not appropriate. e.g. as a write-once read-many format for small datasets for archival or transport purposes.

Beyond OME-Zarr

The recommendations made by the RFC (zarr.json at the root, sorted metadata files) are valuable to all single-file Zarr users, and the only OME-Zarr specific elements are arbitrary markers (the ZIP comment and file extension). While no readers are currently optimised for sorted metadata reads, exposing a larger community to that access pattern makes it more likely that one will eventually be written. Would it be possible to submit this meta-format as e.g. a zarr convention, with more generic markers?

Recommendation

I recommend exploring whether this RFC can be generalised to a broader Zarr context, although if doing so would cause significant delays, accepting it anyway.