7th April, 2021

Attendees: Gregory Lee, Josh Moore, Jackson Brown, Ryan Williams, John Kirkham, Hailey Johnson,

  • zarr_implementations

    • Matthias commitment? Think best effort.

    • Jackson: run as GitHub Action?

    • Other possible designs welcome (skip list)

  • Ryan: more free time

    • also final report deadline end of this month
  • Haily: various fires

  • Josh: still thinking about dimension separators – any opinions?

  • Josh: invited imagecodecs author (cgohlke)

  • Jackson: https://github.com/zarr-developers/zarr-specs/issues/112

    • Various use cases (e.g.


    • John: protocol extension to treat files as 1-D, uint8

      • in v2, .zattrs? as a single chunk….
    • Jackson: no worse than storing OME-XML in the TIFF header…
  • Hailey: https://www.unidata.ucar.edu/blogs/news/entry/netcdf-4-8-0 HOORRAY!

  • Ryan: reporting discussion for the end of the month.

    • Greg: what needs doing on the zarr_implementation side?

    • Josh: largely showing v3 spec, and python done

    • Hailey: Java implementation won’t be v3 on that time scale

  • John: nvidia work on GPU support in Zarr (~Sep. 2019)

    • will be resurrected. 0.5-1 day / week to get that in.

    • allows loading cupy arrays in python (also contrib. to cupy)

    • Josh: sounds related to EOSS4

    • John: hopefully it can handle other types of arrays (sparse,


    • Some numcodecs PRs may need to get in.