diff --git a/.dockerignore b/.dockerignore
new file mode 100644
index 00000000..d3397f9d
--- /dev/null
+++ b/.dockerignore
@@ -0,0 +1,5 @@
+data/**/
+target*
+.netcdf-java
+.tensorstore
+.git
diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index bec61101..57a5b4cd 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -4,38 +4,44 @@ name: Build
 on: [push, pull_request]
 
 jobs:
-  test:
-    name: ${{ matrix.platform }} ${{ matrix.python-version }}
-    runs-on: ${{ matrix.platform }}
 
-    strategy:
-      fail-fast: false
-      matrix:
-        platform: [ubuntu-latest]
-        python-version: [3.7]
+  build:
 
+    runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
+
+      - name: Cache conda
+        uses: actions/cache@v3
+        env:
+          # Increase this value to reset cache if etc/example-environment.yml has not changed
+          CACHE_NUMBER: 0
+        with:
+          path: ~/conda_pkgs_dir
 
       - name: Setup miniconda
-        uses: conda-incubator/setup-miniconda@v1
+        uses: conda-incubator/setup-miniconda@v2
         with:
           auto-update-conda: true
-          channels: conda-forge,ome
+          activate-environment: ZI
+          channels: conda-forge,defaults
+          channel-priority: true
           environment-file: environment.yml
-          python-version: ${{ matrix.python-version }}
+          mamba-version: "*"
         env:
           ACTIONS_ALLOW_UNSECURE_COMMANDS: true
 
       - name: Cache local Maven repository
-        uses: actions/cache@v2
+        uses: actions/cache@v3
         with:
           path: ~/.m2/repository
           key: ${{ runner.os }}-maven-${{ hashFiles('**/pom.xml') }}
           restore-keys: |
             ${{ runner.os }}-maven-
 
-      - name: Run tests
-        shell: bash -l {0}
-        run: make
+      - name: Run build
+        shell: bash -el {0}
+        run: |
+          make write;
+          pytest test/test_read_all.py
diff --git a/.github/workflows/impl.yml b/.github/workflows/impl.yml
new file mode 100644
index 00000000..3287f3df
--- /dev/null
+++ b/.github/workflows/impl.yml
@@ -0,0 +1,90 @@
+---
+name: Implementation tests
+
+on:
+  workflow_call:
+    inputs:
+      implementation:
+        required: true
+        type: string
+      platform:
+        required: true
+        type: string
+      python-version:
+        required: true
+        type: string
+      zarr-python:
+        required: true
+        type: string
+      action:
+        required: true
+        type: string
+
+jobs:
+
+  impl:
+    name: ${{ inputs.implementation }}-${{ inputs.action }}-${{ inputs.platform }}-py${{ inputs.python-version }}-${{ inputs.zarr-python }}
+    runs-on: ${{ inputs.platform }}
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: Cache conda
+        uses: actions/cache@v3
+        env:
+          # Increase this value to reset cache if etc/example-environment.yml has not changed
+          CACHE_NUMBER: 0
+        with:
+          path: ~/conda_pkgs_dir
+          key:
+            ${{ runner.os }}-conda-${{ env.CACHE_NUMBER }}-${{hashFiles( format('{0}/{1}/{2}', 'implementations/', inputs.implementation, '/environment.yml') ) }}
+
+      - name: Setup miniconda
+        uses: conda-incubator/setup-miniconda@v2
+        with:
+          auto-update-conda: true
+          channels: conda-forge,defaults
+          channel-priority: true
+          environment-file: implementations/${{ inputs.implementation }}/environment.yml
+          mamba-version: "*"
+          python-version: ${{ inputs.python-version }}
+          activate-environment: ZI_${{ inputs.implementation }}
+        env:
+          ACTIONS_ALLOW_UNSECURE_COMMANDS: true
+
+      - name: Install zarr dev (optional)
+        shell: bash -l {0}
+        if: ${{ inputs.zarr-python == 'pre' }}
+        run: |
+          python -m pip install git+https://github.com/zarr-developers/zarr-python.git
+
+      - name: Cache local Maven repository
+        uses: actions/cache@v3
+        with:
+          path: ~/.m2/repository
+          key: ${{ runner.os }}-maven-${{ hashFiles('**/pom.xml') }}
+          restore-keys: |
+            ${{ runner.os }}-maven-
+
+      #
+      # Choose read or write based on {{ action }}
+      #
+
+      - name: Download previous output for testing
+        uses: actions/download-artifact@v3
+        if: ${{ inputs.action == 'read' }}
+        with:
+          name: ${{ inputs.implementation }}-${{ inputs.zarr-python }}-data
+          path: data
+
+      - name: Run build
+        shell: bash -l {0}
+        run: make implementations/${{ inputs.implementation }}-${{ inputs.action }}
+
+      - name: Save output for testing
+        uses: actions/upload-artifact@v3
+        if: ${{ inputs.action == 'write' }}
+        with:
+          name: ${{ inputs.implementation }}-${{ inputs.zarr-python }}-data
+          path: data
diff --git a/.github/workflows/zarr-dev.yml b/.github/workflows/zarr-dev.yml
deleted file mode 100644
index c9cc2025..00000000
--- a/.github/workflows/zarr-dev.yml
+++ /dev/null
@@ -1,51 +0,0 @@
----
-name: Build with Zarr dev
-
-on: [push, pull_request]
-
-jobs:
-  test:
-    name: ${{ matrix.platform }} ${{ matrix.python-version }}
-    runs-on: ${{ matrix.platform }}
-
-    strategy:
-      fail-fast: true
-      matrix:
-        platform: [ubuntu-latest]
-        python-version: [3.7]
-
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v2
-
-      - name: Setup miniconda
-        uses: conda-incubator/setup-miniconda@v2
-        with:
-          auto-update-conda: true
-          channels: conda-forge,ome
-          environment-file: environment.yml
-          python-version: ${{ matrix.python-version }}
-        env:
-          ACTIONS_ALLOW_UNSECURE_COMMANDS: true
-
-      - name: Install zarr dev
-        shell: bash -l {0}
-        run: |
-          python -m pip install git+https://github.com/zarr-developers/zarr-python.git
-
-      - name: Run tests
-        shell: bash -l {0}
-        run: make
-
-      - name: Generate Report
-        shell: bash -l {0}
-        run: |
-            python test/test_read_all.py
-
-      - name: Archive test report artifacts
-        uses: actions/upload-artifact@v2
-        with:
-          name: test-report
-          path: |
-              report.md
-              report.html
diff --git a/.gitignore b/.gitignore
index 03b3105c..c9cee769 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,8 +1,9 @@
 target*
 __pycache__/
-generate_data/xtensor_zarr/build
+implmenetations/xtensor_zarr/build
 node_modules/
 report.*
 
 # ignore data subdirectories
 data/**/
+*iml
diff --git a/Dockerfile b/Dockerfile
index ee308a08..d551d51d 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -2,7 +2,7 @@ FROM continuumio/miniconda3
 
 WORKDIR /src
 COPY environment.yml /src/environment.yml
-RUN apt-get update -y && apt install -y freeglut3-dev
+RUN apt-get update -y && apt install -y freeglut3-dev # Unsure why freeglut is here
 RUN conda env create -f environment.yml -n z
 SHELL ["conda", "run", "-n", "z", "/bin/bash", "-c"]
 
diff --git a/Makefile b/Makefile
index e1888d6f..ad31904a 100644
--- a/Makefile
+++ b/Makefile
@@ -1,46 +1,107 @@
+IMPLEMENTATIONS=$(wildcard implementations/*)
+CURRENT_DIR = $(shell pwd)
+
+define HELP_TEXT
+make [target]
+
+Target(s):
+  write                generate data for all implementations
+  list                 print directory\tpath pairs for all written data
+  read                 read all data written by all implementations
+  read-fast            like read, but do not re-run `write`
+
+Notes:
+  - Each implementation has a conda environment named ZI_<IMPL>
+
+endef
+
+export HELP_TEXT
+
+.PHONY: help
+help:
+	@echo "$$HELP_TEXT"
+
+.PHONY: report
+
+report: data
+	python test/test_read_all.py
+
+.PHONY: test data
+
+ifeq ($(TEST),) #################################################
+# If TEST is not set, by default build everything, generate
+# data for all implementations, and then run all pytests.
+
 test: data
-	pytest -v
+	pytest -v -k W
+
+data: $(IMPLEMENTATIONS)
+
+else
+# Otherwise, focus on a single implementation, only generating
+# its data and using the "-k W-" keyword to limit which pytests
+# get run
+
+test: implementations/$(TEST)
+	pytest -v -k W-$(TEST)
+
+data: implementations/$(TEST)
+
+endif ##########################################################
+
 
 data/reference_image.png:
 	python generate_reference_image.py
 
-.PHONY: jzarr
-jzarr: data/reference_image.png
-	bash generate_data/jzarr/generate_data.sh
+define mk-impl-target
+# For each of the items in our "implementations" directory,
+# create targets which depend on the reference data and
+# call the "driver.sh" script as necessary.
 
-.PHONY: n5java
-n5java: data/reference_image.png
-	bash generate_data/n5-java/generate_data.sh
+.PHONY: write list read-fast read $1 $1/ $1-list $1-read-fast $1-read $1-write $1-destroy clean
 
-.PHONY: pyn5
-pyn5: data/reference_image.png
-	python generate_data/generate_pyn5.py
+write: $1-write
+list: $1-list
 
-.PHONY: z5py
-z5py: data/reference_image.png
-	python generate_data/generate_z5py.py
+read-fast: $1-read-fast
+read: $1-read
 
-.PHONY: zarr
-zarr: data/reference_image.png
-	python generate_data/generate_zarr.py
+$1-write: data/reference_image.png
+	@if test -e $1/.skip; \
+	    then >&2 echo "Skipping $1 -- $$(shell test -e $1/.skip && cat $1/.skip)"; \
+	else \
+	    bash $1/driver.sh write; \
+	fi
 
-.PHONY: zarrita
-zarrita: data/reference_image.png
-	python generate_data/generate_zarrita.py
+$1-list:
+	@if test -e $1/.skip; \
+	    then >&2 echo "Skipping $1 -- $$(shell test -e $1/.skip && cat $1/.skip)"; \
+	else \
+	    bash $1/driver.sh list; \
+	fi
 
-.PHONY: js
-js: data/reference_image.png
-	bash generate_data/js/generate_data.sh
+$1-read-fast:
+	@if test -e $1/.skip; \
+	    then >&2 echo "Skipping $1 -- $$(shell test -e $1/.skip && cat $1/.skip)"; \
+	else \
+	    bash $1/driver.sh read $(DIR) $(DATASET); \
+	fi
 
-.PHONY: xtensor_zarr
-xtensor_zarr: data/reference_image.png
-	bash generate_data/xtensor_zarr/generate_data.sh
 
-.PHONY: data
-data: jzarr n5java pyn5 z5py zarr js xtensor_zarr zarrita
+$1-read: write $1-read-fast
 
-.PHONY: test
 
-.PHONY: report
-report: data
-	python test/test_read_all.py
+# Alias for read & write
+$1: $1-write $1-read
+
+# Alias in case the trailing slash is included
+$1/: $1
+
+# Additional target to cleanup the environment
+$1-destroy:
+	bash $1/driver.sh destroy
+
+clean: $1-destroy
+
+endef
+$(foreach impl,$(IMPLEMENTATIONS),$(eval $(call mk-impl-target,$(impl))))
diff --git a/README.md b/README.md
index cd0bda30..5b1a22d7 100644
--- a/README.md
+++ b/README.md
@@ -5,7 +5,6 @@ Test for compatibility. See [doc/development_overview.md](doc/development_overvi
 
 ## Implementations currently tested
 
-
 * https://github.com/bcdev/jzarr
 * https://github.com/saalfeldlab/n5-zarr
 * https://github.com/aschampion/rust-n5
@@ -13,7 +12,7 @@ Test for compatibility. See [doc/development_overview.md](doc/development_overvi
 * https://github.com/gzuidhof/zarr.js
 * https://github.com/zarr-developers/zarr-python
 * https://github.com/constantinpape/z5
-
+* https://gihutb.com/grimbough/Rarr
 
 ## Other implementations
 
@@ -23,3 +22,13 @@ Test for compatibility. See [doc/development_overview.md](doc/development_overvi
 * [Zarr.jl](https://github.com/meggart/Zarr.jl) #42
 * https://github.com/freeman-lab/zarr-js
 * [GDAL >= 3.4](https://gdal.org/drivers/raster/zarr.html)
+
+## Running locally
+
+* Create an environment: `conda env create -n ZI -f environment.yml`
+* Run `make`
+
+## Other features
+
+* `touch implementations/{impl}/.skip` to disable an implementation
+* Use `make NODEBUG=1 ...` to quiet output
diff --git a/generate_data/generate_reference_image.py b/data/generate_reference_image.py
similarity index 77%
rename from generate_data/generate_reference_image.py
rename to data/generate_reference_image.py
index 1780d7b1..dec8da3d 100644
--- a/generate_data/generate_reference_image.py
+++ b/data/generate_reference_image.py
@@ -1,9 +1,11 @@
+#!/usr/bin/env python
+
 from skimage.data import astronaut
 from skimage.io import imsave
 
 
 def write_reference_image():
-    path = '../data/reference_image.png'
+    path = 'reference_image.png'
     im = astronaut()
     imsave(path, im)
 
diff --git a/doc/development_overview.md b/doc/development_overview.md
index 2a503a04..0d7d7d43 100644
--- a/doc/development_overview.md
+++ b/doc/development_overview.md
@@ -2,7 +2,7 @@
 
 ## Overview
 
-This repository contains scripts to generate datasets in zarr-v2, zarr-v3 and
+This repository contains scripts to generate datasets in Zarr-v2, Zarr-v3 and
 N5 formats via a number of different implementations. Once generated, the test
 suite will attempt to have each library read all datasets with a supported
 format.
@@ -44,7 +44,7 @@ conda activate zarr_impl_dev
 ## Data Generation
 
 All test data is currently generated from a common image file that gets
-generated by the script `generate_data/generate_reference_image.py`. Each
+generated by the script `data/generate_reference_image.py`. Each
 library that generates data currently has either a python script or a shell
 script that will generate datasets for the supported file types and codecs.
 Some implementations also generate versions using both flat and nested file
diff --git a/environment.yml b/environment.yml
index 8f651a0f..f3dad3f1 100644
--- a/environment.yml
+++ b/environment.yml
@@ -2,21 +2,10 @@ channels:
   - conda-forge
   - defaults
 dependencies:
-  - openjdk
-  - maven
   - make
-  - cmake
-  - xtensor-zarr >=0.0.8|=0.0.7=*_1
-  - openimageio
-  - nodejs
-  - z5py >= 2.0.10
-  - python == 3.7.9
+  - python
   - scikit-image
   - pytest
-  - zarr >= 2.8.3
   - pip
   - pandas
   - tabulate
-  - pip:
-      - pyn5
-      - git+https://github.com/grlee77/zarrita.git@codec_update
diff --git a/generate_data/generate_pyn5.py b/generate_data/generate_pyn5.py
deleted file mode 100755
index 99b10c34..00000000
--- a/generate_data/generate_pyn5.py
+++ /dev/null
@@ -1,24 +0,0 @@
-#!/usr/bin/env python
-from pathlib import Path
-import pyn5
-from skimage.io import imread
-
-# choose chunks s.t. we do have overhanging edge-chunks
-CHUNKS = (100, 100, 1)
-
-
-def generate_n5_format(compressors=pyn5.CompressionType):
-    here = Path(__file__).resolve().parent
-    data_dir = here.parent / "data"
-    path = data_dir / "pyn5.n5"
-
-    im = imread(data_dir / "reference_image.png")
-
-    f = pyn5.File(path, pyn5.Mode.CREATE_TRUNCATE)
-    for compressor in compressors:
-        name = str(compressor)
-        f.create_dataset(name, data=im, chunks=CHUNKS, compression=compressor)
-
-
-if __name__ == '__main__':
-    generate_n5_format()
diff --git a/generate_data/generate_z5py.py b/generate_data/generate_z5py.py
deleted file mode 100644
index 8106cf71..00000000
--- a/generate_data/generate_z5py.py
+++ /dev/null
@@ -1,41 +0,0 @@
-import z5py
-from skimage.data import astronaut
-
-# choose chunks s.t. we do have overhanging edge-chunks
-CHUNKS = (100, 100, 1)
-
-# options for the different compressors
-COMPRESSION_OPTIONS = {"blosc": {"codec": "lz4"}}
-
-
-# TODO support more compressors:
-# - more compressors in numcodecs
-# - more blosc codecs
-def generate_zarr_format(compressors=['gzip', 'blosc', 'zlib', 'raw']):
-    path = 'data/z5py.zr'
-    im = astronaut()
-
-    f = z5py.File(path, mode='w')
-    for compressor in compressors:
-        copts = COMPRESSION_OPTIONS.get(compressor, {})
-        name = (
-            compressor
-            if compressor != "blosc"
-            else "%s/%s" % (compressor, copts.get("codec"))
-        )
-        f.create_dataset(name, data=im, compression=compressor, chunks=CHUNKS, **copts)
-
-
-def generate_n5_format(compressors=['gzip', 'raw']):
-    path = 'data/z5py.n5'
-    im = astronaut()
-
-    f = z5py.File(path, mode='w')
-    for compressor in compressors:
-        name = compressor
-        f.create_dataset(name, data=im, chunks=CHUNKS, compression=compressor)
-
-
-if __name__ == '__main__':
-    generate_zarr_format()
-    generate_n5_format()
diff --git a/generate_data/generate_zarrita.py b/generate_data/generate_zarrita.py
deleted file mode 100644
index 2765dea4..00000000
--- a/generate_data/generate_zarrita.py
+++ /dev/null
@@ -1,42 +0,0 @@
-import zarrita
-import numcodecs
-from skimage.data import astronaut
-
-# choose chunks s.t. we do have overhanging edge-chunks
-CHUNKS = (100, 100, 1)
-STR_TO_COMPRESSOR = {
-    "gzip": numcodecs.GZip,
-    "blosc": numcodecs.Blosc,
-    "zlib": numcodecs.Zlib,
-}
-COMPRESSION_OPTIONS = {"blosc": {"cname": "lz4"}}
-
-
-def generate_zr3_format(compressors=['gzip', 'blosc', 'zlib', None],
-                        nested=True):
-    im = astronaut()
-    if nested:
-        chunk_separator = '/'
-        fname = 'data/zarrita_nested.zr3'
-    else:
-        chunk_separator = '.'
-        fname = 'data/zarrita.zr3'
-    h = zarrita.create_hierarchy(fname)
-    for compressor in compressors:
-        copts = COMPRESSION_OPTIONS.get(compressor, {})
-        if compressor is None:
-            name = "raw"
-        elif compressor == "blosc":
-            name = "%s/%s" % (compressor, copts.get("cname"))
-        else:
-            name = compressor
-        compressor_impl = STR_TO_COMPRESSOR[compressor](**copts) if compressor is not None else None
-        a = h.create_array('/' + name, shape=im.shape, chunk_shape=CHUNKS,
-                           chunk_separator=chunk_separator, dtype=im.dtype,
-                           compressor=compressor_impl)
-        a[...] = im
-
-
-if __name__ == '__main__':
-    for nested in [False, True]:
-        generate_zr3_format(nested=nested)
diff --git a/generate_data/js/generate_data.sh b/generate_data/js/generate_data.sh
deleted file mode 100755
index c70e51f0..00000000
--- a/generate_data/js/generate_data.sh
+++ /dev/null
@@ -1,6 +0,0 @@
-# cd to this directory
-# https://stackoverflow.com/a/6393573/2700168
-cd "${0%/*}"
-
-npm install
-npm start
diff --git a/generate_data/jzarr/generate_data.sh b/generate_data/jzarr/generate_data.sh
deleted file mode 100755
index c860ea03..00000000
--- a/generate_data/jzarr/generate_data.sh
+++ /dev/null
@@ -1,19 +0,0 @@
-# cd to this directory
-# https://stackoverflow.com/a/6393573/2700168
-cd "${0%/*}"
-
-set -e
-set -u
-set -x
-
-MVN_FLAGS=${MVN_FLAGS:-"--no-transfer-progress"}
-mvn "${MVN_FLAGS}" clean package
-
-java -cp target/jzarr-1.0.0.jar zarr_implementations.jzarr.App "$@" && {
-    # Workaround for: https://github.com/bcdev/jzarr/issues/25
-    find ../../data/jzarr* -name .zarray -exec sed -ibak 's/>u1/|u1/' {} \;
-} || {
-    echo jzarr failed
-    exit 2
-}
-
diff --git a/generate_data/n5-java/generate_data.sh b/generate_data/n5-java/generate_data.sh
deleted file mode 100755
index 2607bea3..00000000
--- a/generate_data/n5-java/generate_data.sh
+++ /dev/null
@@ -1,8 +0,0 @@
-# cd to this directory
-# https://stackoverflow.com/a/6393573/2700168
-cd "${0%/*}"
-
-MVN_FLAGS=${MVN_FLAGS:-"--no-transfer-progress"}
-mvn "${MVN_FLAGS}" clean package
-
-java -cp target/n5_java-1.0.0.jar zarr_implementations.n5_java.App
diff --git a/generate_data/xtensor_zarr/generate_data.sh b/generate_data/xtensor_zarr/generate_data.sh
deleted file mode 100755
index b6e66582..00000000
--- a/generate_data/xtensor_zarr/generate_data.sh
+++ /dev/null
@@ -1,11 +0,0 @@
-# cd to this directory
-# https://stackoverflow.com/a/6393573/2700168
-cd "${0%/*}"
-
-rm -rf build
-mkdir build
-cd build
-export LDFLAGS="${LDFLAGS} -Wl,-rpath,$CONDA_PREFIX/lib -Wl,-rpath,$PWD"
-export LINKFLAGS="${LDFLAGS}"
-cmake .. -DCMAKE_PREFIX_PATH=$CONDA_PREFIX -DCMAKE_INSTALL_PREFIX=$CONDA_PREFIX -DCMAKE_INSTALL_LIBDIR=lib
-make run
diff --git a/implementations/.bash_driver.sh b/implementations/.bash_driver.sh
new file mode 100644
index 00000000..f52650b0
--- /dev/null
+++ b/implementations/.bash_driver.sh
@@ -0,0 +1,28 @@
+#!/usr/bin/env bash
+#
+# This is re-usable driver code for all of the implementations.
+#
+
+set -e
+set -o pipefail
+
+argparse(){
+    case "${1}" in
+        write)
+            [[ -z "${NODEBUG}" ]] && >&2 echo "Generating data..."
+            zi_write;;
+        list)
+            shift;
+            zi_list "$@";;
+        read)
+            shift;
+            [[ -z "${NODEBUG}" ]] && >&2 echo "Verifying data..."
+            zi_read "$@";;
+        destroy)
+            [[ -z "${NODEBUG}" ]] && >&2 echo "Tearing down..."
+            zi_destroy;;
+        *)
+            [[ -z "${NODEBUG}" ]] && >&2 echo "Unknown command: ${1}"
+            exit 2;;
+    esac
+}
diff --git a/implementations/.conda_driver.sh b/implementations/.conda_driver.sh
new file mode 100644
index 00000000..592487eb
--- /dev/null
+++ b/implementations/.conda_driver.sh
@@ -0,0 +1,44 @@
+#!/usr/bin/env bash
+#
+# This is re-usable driver code for all of the implementations
+# that make use of a conda environment file.
+#
+
+set -e
+set -o pipefail
+
+## Setup based on mamba versus conda installation
+if command -v mamba &> /dev/null
+then
+    COMMAND=mamba
+else
+    COMMAND=conda
+fi
+
+create_or_activate(){
+
+    if { $COMMAND env list | grep $ENVNAME; } >/dev/null 2>&1; then
+        [[ -z "${NODEBUG}" ]] && >&2 echo "Using $ENVNAME"
+    else
+        [[ -z "${NODEBUG}" ]] && >&2 echo "Creating $ENVNAME"
+        $COMMAND env create -n $ENVNAME -f $IMPL/environment.yml
+    fi
+    export MAMBA_ROOT_PREFIX=$(conda info --base -q)
+    export MAMBA_EXE=${MAMBA_ROOT_PREFIX}/bin/mamba
+    export CONDA_EXE=${MAMBA_ROOT_PREFIX}/bin/conda
+    . $MAMBA_ROOT_PREFIX/etc/profile.d/conda.sh
+    . $MAMBA_ROOT_PREFIX/etc/profile.d/mamba.sh
+
+    [[ -z "${NODEBUG}" ]] && >&2 echo "Activating $ENVNAME"
+    $COMMAND activate $ENVNAME
+}
+
+zi_destroy(){
+
+    if { $COMMAND env list | grep $ENVNAME; } >/dev/null 2>&1; then
+        [[ -z "${NODEBUG}" ]] && >&2 echo "Destroying $ENVNAME"
+        $COMMAND env remove -y -n $ENVNAME
+    else
+        >&2 echo "No known env: $ENVNAME"
+    fi
+}
diff --git a/implementations/Rarr/.skip b/implementations/Rarr/.skip
new file mode 100644
index 00000000..523b9b00
--- /dev/null
+++ b/implementations/Rarr/.skip
@@ -0,0 +1 @@
+built under R version 4.3.2
diff --git a/implementations/Rarr/driver.sh b/implementations/Rarr/driver.sh
new file mode 100755
index 00000000..9858ec4b
--- /dev/null
+++ b/implementations/Rarr/driver.sh
@@ -0,0 +1,37 @@
+#!/usr/bin/env bash
+ENVNAME=ZI_Rarr
+
+# Standard bootstrapping
+IMPL=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
+ROOT=$( dirname $IMPL)
+
+zi_write(){
+    create_or_activate
+
+    cd "${IMPL}"
+
+    Rscript install_packages.R
+    Rscript generate_Rarr.R
+}
+
+zi_list(){
+    create_or_activate
+
+    cd "${IMPL}"
+
+    Rscript install_packages.R
+    Rscript generate_Rarr.R -list
+}
+
+zi_read(){
+    create_or_activate
+
+    cd "${IMPL}"
+
+    Rscript install_packages.R
+    Rscript verify_data.R "$@"
+}
+
+. $ROOT/.conda_driver.sh
+. $ROOT/.bash_driver.sh
+argparse "$@"
diff --git a/implementations/Rarr/environment.yml b/implementations/Rarr/environment.yml
new file mode 100644
index 00000000..36a94516
--- /dev/null
+++ b/implementations/Rarr/environment.yml
@@ -0,0 +1,7 @@
+channels:
+  - defaults
+  - bioconda
+dependencies:
+  - bioconductor-rarr
+variables:
+  LC_ALL: C.UTF-8
diff --git a/implementations/Rarr/generate_Rarr.R b/implementations/Rarr/generate_Rarr.R
new file mode 100644
index 00000000..d41e7c7a
--- /dev/null
+++ b/implementations/Rarr/generate_Rarr.R
@@ -0,0 +1,33 @@
+library(loder)
+library(Rarr)
+
+img <- loder::readPng("../../data/reference_image.png")
+
+chunk_dim <- c(100, 100, 1)
+
+for (sep in c("_flat", "_nested")) {
+  for (codec in c("blosc/lz4", "zlib", "gzip", "raw")) {
+    dir_name <- paste0("Rarr", sep, ".zr")
+    output_name <- file.path("../../data", dir_name, codec)
+
+    dir.create(output_name, recursive = TRUE, showWarnings = FALSE)
+
+    dim_sep <- ifelse(sep == "_flat", yes = ".", no = "/")
+
+    compressor <- switch(codec,
+      "blosc/lz4" = Rarr:::use_blosc(),
+      "zlib" = Rarr:::use_zlib(),
+      "gzip" = Rarr::use_gzip(),
+      "raw" = NULL
+    )
+
+    write_zarr_array(
+      x = img,
+      zarr_array_path = output_name,
+      chunk_dim = chunk_dim,
+      compressor = compressor,
+      dimension_separator = dim_sep,
+      order = "C"
+    )
+  }
+}
diff --git a/implementations/Rarr/install_packages.R b/implementations/Rarr/install_packages.R
new file mode 100644
index 00000000..651f46b6
--- /dev/null
+++ b/implementations/Rarr/install_packages.R
@@ -0,0 +1,8 @@
+chooseCRANmirror(ind = 1)
+if (!require("loder", quietly = TRUE)) {
+    install.packages("loder", )
+}
+if (!require("Rarr", quietly = TRUE)) {
+    #remotes::install_git("https://git.bioconductor.org/packages/Rarr", upgrade = "never")
+    remotes::install_git("https://github.com/grimbough/Rarr.git/", ref = "main", upgrade = "never")
+}
diff --git a/implementations/Rarr/verify_data.R b/implementations/Rarr/verify_data.R
new file mode 100644
index 00000000..8b5fde72
--- /dev/null
+++ b/implementations/Rarr/verify_data.R
@@ -0,0 +1,17 @@
+args <- commandArgs(trailingOnly = TRUE)
+
+stopifnot(length(args) == 2)
+
+fpath <- args[1]
+ds_name <- args[2]
+
+library(Rarr)
+library(reticulate)
+np <- import("numpy")
+
+zarr_array <- file.path(fpath, ds_name)
+
+x <- read_zarr_array(zarr_array_path = zarr_array)
+
+a <- np$array(x)
+np$save("a.npy", a)
diff --git a/implementations/Rarr/verify_data_internal.R b/implementations/Rarr/verify_data_internal.R
new file mode 100644
index 00000000..99f3f266
--- /dev/null
+++ b/implementations/Rarr/verify_data_internal.R
@@ -0,0 +1,27 @@
+args <- commandArgs(trailingOnly = TRUE)
+
+stopifnot(length(args) == 2)
+
+fpath <- args[1]
+ds_name <- args[2]
+
+source("implementations/Rarr/install_packages.R")
+
+library(loder)
+library(Rarr)
+
+## Read the reference image.  We strip the "loder" class so it is a 
+## regular array, making the comparison easier
+reference_img <- loder::readPng("data/reference_image.png")
+class(reference_img) <- "array"
+
+## read the zarr input
+zarr_array <- file.path(fpath, ds_name)
+x <- read_zarr_array(zarr_array_path = zarr_array)
+
+## if the values are different quit
+if(!isTRUE(all.equal(reference_img, x, check.attributes = FALSE))) {
+    stop("Input and reference image are different")
+}
+
+quit(save = "no", status = 0)
diff --git a/implementations/js/driver.sh b/implementations/js/driver.sh
new file mode 100755
index 00000000..1821c3eb
--- /dev/null
+++ b/implementations/js/driver.sh
@@ -0,0 +1,33 @@
+#!/usr/bin/env bash
+ENVNAME=ZI_js
+
+# Standard bootstrapping
+IMPL=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
+ROOT=$( dirname $IMPL)
+
+zi_write(){
+    create_or_activate
+
+    cd "${IMPL}"
+
+    npm install
+    npm start
+}
+
+zi_list(){
+    create_or_activate
+
+    cd "${IMPL}"
+
+    npm install --silent
+    npm run --silent start -- --list "$@"
+}
+
+zi_read(){
+    cd "${IMPL}"
+    npm run start -- --verify "$@"
+}
+
+. $ROOT/.conda_driver.sh
+. $ROOT/.bash_driver.sh
+argparse "$@"
diff --git a/implementations/js/environment.yml b/implementations/js/environment.yml
new file mode 100644
index 00000000..4c3e61e9
--- /dev/null
+++ b/implementations/js/environment.yml
@@ -0,0 +1,5 @@
+channels:
+  - conda-forge
+  - defaults
+dependencies:
+  - nodejs
diff --git a/generate_data/js/package-lock.json b/implementations/js/package-lock.json
similarity index 60%
rename from generate_data/js/package-lock.json
rename to implementations/js/package-lock.json
index c03611b7..1128d74e 100644
--- a/generate_data/js/package-lock.json
+++ b/implementations/js/package-lock.json
@@ -1,59 +1,91 @@
 {
+  "name": "js",
+  "lockfileVersion": 3,
   "requires": true,
-  "lockfileVersion": 1,
-  "dependencies": {
-    "eventemitter3": {
+  "packages": {
+    "": {
+      "dependencies": {
+        "minimist": "1.2.8",
+        "pngjs": "^6.0.0",
+        "zarr": "^0.4.0"
+      }
+    },
+    "node_modules/eventemitter3": {
       "version": "4.0.7",
       "resolved": "https://registry.npmjs.org/eventemitter3/-/eventemitter3-4.0.7.tgz",
       "integrity": "sha512-8guHBZCwKnFhYdHr2ysuRWErTwhoN2X8XELRlrRwpmfeY2jjuUN4taQMsULKUVo1K4DvZl+0pgfyoysHxvmvEw=="
     },
-    "numcodecs": {
+    "node_modules/minimist": {
+      "version": "1.2.8",
+      "resolved": "https://registry.npmjs.org/minimist/-/minimist-1.2.8.tgz",
+      "integrity": "sha512-2yyAR8qBkN3YuheJanUpWC5U3bb5osDywNB8RzDVlDwDHbocAJveqqj1u8+SVD7jkWT4yvsHCpWqqWqAxb0zCA==",
+      "license": "MIT",
+      "funding": {
+        "url": "https://github.com/sponsors/ljharb"
+      }
+    },
+    "node_modules/numcodecs": {
       "version": "0.1.1",
       "resolved": "https://registry.npmjs.org/numcodecs/-/numcodecs-0.1.1.tgz",
       "integrity": "sha512-UjKulZ6GIFKLdBIczEbsoXNZQmiHafpoIdo39YcdecHVGyMKh0+azsfHTrybXm5RZwepqLZv24mkjqGdZGm24Q==",
-      "requires": {
+      "dependencies": {
         "pako": "^1.0.11"
       }
     },
-    "p-finally": {
+    "node_modules/p-finally": {
       "version": "1.0.0",
       "resolved": "https://registry.npmjs.org/p-finally/-/p-finally-1.0.0.tgz",
-      "integrity": "sha1-P7z7FbiZpEEjs0ttzBi3JDNqLK4="
+      "integrity": "sha1-P7z7FbiZpEEjs0ttzBi3JDNqLK4=",
+      "engines": {
+        "node": ">=4"
+      }
     },
-    "p-queue": {
+    "node_modules/p-queue": {
       "version": "6.2.0",
       "resolved": "https://registry.npmjs.org/p-queue/-/p-queue-6.2.0.tgz",
       "integrity": "sha512-B2LXNONcyn/G6uz2UBFsGjmSa0e/br3jznlzhEyCXg56c7VhEpiT2pZxGOfv32Q3FSyugAdys9KGpsv3kV+Sbg==",
-      "requires": {
+      "dependencies": {
         "eventemitter3": "^4.0.0",
         "p-timeout": "^3.1.0"
+      },
+      "engines": {
+        "node": ">=8"
       }
     },
-    "p-timeout": {
+    "node_modules/p-timeout": {
       "version": "3.2.0",
       "resolved": "https://registry.npmjs.org/p-timeout/-/p-timeout-3.2.0.tgz",
       "integrity": "sha512-rhIwUycgwwKcP9yTOOFK/AKsAopjjCakVqLHePO3CC6Mir1Z99xT+R63jZxAT5lFZLa2inS5h+ZS2GvR99/FBg==",
-      "requires": {
+      "dependencies": {
         "p-finally": "^1.0.0"
+      },
+      "engines": {
+        "node": ">=8"
       }
     },
-    "pako": {
+    "node_modules/pako": {
       "version": "1.0.11",
       "resolved": "https://registry.npmjs.org/pako/-/pako-1.0.11.tgz",
       "integrity": "sha512-4hLB8Py4zZce5s4yd9XzopqwVv/yGNhV1Bl8NTmCq1763HeK2+EwVTv+leGeL13Dnh2wfbqowVPXCIO0z4taYw=="
     },
-    "pngjs": {
+    "node_modules/pngjs": {
       "version": "6.0.0",
       "resolved": "https://registry.npmjs.org/pngjs/-/pngjs-6.0.0.tgz",
-      "integrity": "sha512-TRzzuFRRmEoSW/p1KVAmiOgPco2Irlah+bGFCeNfJXxxYGwSw7YwAOAcd7X28K/m5bjBWKsC29KyoMfHbypayg=="
+      "integrity": "sha512-TRzzuFRRmEoSW/p1KVAmiOgPco2Irlah+bGFCeNfJXxxYGwSw7YwAOAcd7X28K/m5bjBWKsC29KyoMfHbypayg==",
+      "engines": {
+        "node": ">=12.13.0"
+      }
     },
-    "zarr": {
+    "node_modules/zarr": {
       "version": "0.4.0",
       "resolved": "https://registry.npmjs.org/zarr/-/zarr-0.4.0.tgz",
       "integrity": "sha512-zvxdX3aRWxjy6H3OtA7R05NNZvRKxn/7bkNJhUsVKKbNoJ3DBqYERQfzI4WfAV1OTcclqvlYwkQ7DWsGJA5QEw==",
-      "requires": {
+      "dependencies": {
         "numcodecs": "^0.1.0",
         "p-queue": "6.2.0"
+      },
+      "engines": {
+        "node": ">=8.0.0"
       }
     }
   }
diff --git a/generate_data/js/package.json b/implementations/js/package.json
similarity index 85%
rename from generate_data/js/package.json
rename to implementations/js/package.json
index 60d38ffc..7d67cecb 100644
--- a/generate_data/js/package.json
+++ b/implementations/js/package.json
@@ -4,6 +4,7 @@
     "start": "node src/index.js"
   },
   "dependencies": {
+    "minimist": "1.2.8",
     "pngjs": "^6.0.0",
     "zarr": "^0.4.0"
   }
diff --git a/generate_data/js/src/fsstore.js b/implementations/js/src/fsstore.js
similarity index 100%
rename from generate_data/js/src/fsstore.js
rename to implementations/js/src/fsstore.js
diff --git a/generate_data/js/src/index.js b/implementations/js/src/index.js
similarity index 67%
rename from generate_data/js/src/index.js
rename to implementations/js/src/index.js
index 02998710..da1d68b6 100644
--- a/generate_data/js/src/index.js
+++ b/implementations/js/src/index.js
@@ -1,6 +1,7 @@
 import fs from "fs";
 import p from "path";
 import pkg from "pngjs";
+import minimist from "minimist";
 const { PNG } = pkg;
 
 import { openGroup, NestedArray, slice } from "zarr";
@@ -34,21 +35,39 @@ function getName(config) {
   return config.id;
 }
 
-async function generateZarrFormat(codecIds = ["gzip", "blosc", "zlib", null]) {
+async function generateZarrFormat(listOnly, codecIds = ["gzip", "blosc", "zlib", null]) {
   const path = p.join("..", "..", "data", "js.zr");
   const img = imread(p.join("..", "..", "data", "reference_image.png"));
 
-  fs.rmdirSync(path, { recursive: true, force: true });
+  if (!listOnly && fs.existsSync(path)) {
+    fs.rmdirSync(path, { recursive: true, force: true });
+  }
+
   const grp = await open(path);
   for (const id of codecIds) {
     const config = id ? STR_TO_COMPRESSOR[id] : null;
     const name = getName(config);
-    grp.createDataset(name, undefined, img, {
-      compressor: config,
-      chunks: CHUNKS,
-      fillValue: 0,
-    });
+    if (listOnly) {
+        console.log(path + "\t" + name);
+    } else {
+      grp.createDataset(name, undefined, img, {
+        compressor: config,
+        chunks: CHUNKS,
+        fillValue: 0,
+      });
+    }
   }
 }
 
-generateZarrFormat();
+function main(){
+    var argv = minimist(process.argv.slice(2), {
+        boolean: ["list", "verify"],
+    });
+    if (argv.verify) {
+        verifyZarrFormat(verify);
+    } else {
+        generateZarrFormat(argv.list);
+    }
+}
+
+main();
diff --git a/implementations/jzarr/driver.sh b/implementations/jzarr/driver.sh
new file mode 100755
index 00000000..df8a830f
--- /dev/null
+++ b/implementations/jzarr/driver.sh
@@ -0,0 +1,52 @@
+#!/usr/bin/env bash
+ENVNAME=ZI_jzarr
+
+# Standard bootstrapping
+IMPL=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
+ROOT=$( dirname $IMPL)
+
+zi_write(){
+    create_or_activate
+
+    cd "${IMPL}"
+
+    MVN_FLAGS=${MVN_FLAGS:-"-q --no-transfer-progress"}
+    mvn ${MVN_FLAGS} package
+
+    java -cp target/jzarr-1.0.0.jar zarr_implementations.jzarr.App "$@" && {
+        # Workaround for: https://github.com/bcdev/jzarr/issues/25
+        find ../../data/jzarr* -name .zarray -exec sed -ibak 's/>u1/|u1/' {} \;
+    } || {
+        echo jzarr failed
+        exit 2
+    }
+}
+
+zi_list(){
+    create_or_activate
+
+    cd "${IMPL}"
+
+    MVN_FLAGS=${MVN_FLAGS:-"-q --no-transfer-progress"}
+    mvn ${MVN_FLAGS} package
+    #notrap_outerr
+
+    java -cp target/jzarr-1.0.0.jar zarr_implementations.jzarr.App -list
+}
+
+zi_read(){
+    create_or_activate
+
+    cd "${IMPL}"
+
+    MVN_FLAGS=${MVN_FLAGS:-"-q --no-transfer-progress"}
+    mvn ${MVN_FLAGS} package
+    #notrap_outerr
+
+    java -cp target/jzarr-1.0.0.jar zarr_implementations.jzarr.App -verify "$@"
+}
+
+
+. $ROOT/.conda_driver.sh
+. $ROOT/.bash_driver.sh
+argparse "$@"
diff --git a/implementations/jzarr/environment.yml b/implementations/jzarr/environment.yml
new file mode 100644
index 00000000..a7a62cbb
--- /dev/null
+++ b/implementations/jzarr/environment.yml
@@ -0,0 +1,7 @@
+channels:
+  - conda-forge
+  - defaults
+dependencies:
+  - openjdk
+  - maven
+  - blosc
diff --git a/generate_data/jzarr/pom.xml b/implementations/jzarr/pom.xml
similarity index 100%
rename from generate_data/jzarr/pom.xml
rename to implementations/jzarr/pom.xml
diff --git a/generate_data/jzarr/src/main/java/zarr_implementations/jzarr/App.java b/implementations/jzarr/src/main/java/zarr_implementations/jzarr/App.java
similarity index 87%
rename from generate_data/jzarr/src/main/java/zarr_implementations/jzarr/App.java
rename to implementations/jzarr/src/main/java/zarr_implementations/jzarr/App.java
index 4cc39d15..2a8a90b7 100644
--- a/generate_data/jzarr/src/main/java/zarr_implementations/jzarr/App.java
+++ b/implementations/jzarr/src/main/java/zarr_implementations/jzarr/App.java
@@ -80,11 +80,14 @@ private static int[] getArrayData(ZarrArray zarr) throws Exception {
 
     public static void main(String args[]) throws Exception {
 
-        if (args.length != 0 && args.length != 3) {
+        if (args.length != 0 && args.length != 1 && args.length != 3) {
             System.out.println("usage: App");
+            System.out.println("usage: App -list");
             System.out.println("usage: App -verify fpath dsname");
             System.exit(2);  // EARLY EXIT
-        } else if (args.length == 3) {
+        }
+
+        if (args.length == 3) {
             String fpath = args[1];
             String dsname = args[2];
             ZarrArray verification = ZarrGroup.open(fpath).openArray(dsname);
@@ -105,6 +108,11 @@ public static void main(String args[]) throws Exception {
             return;  // EARLY EXIT
         }
 
+        boolean listOnly = false;
+        if (args.length == 1) {
+            listOnly = true;
+        }
+
         int[] data = getTestData();
 
         final ZarrGroup container = ZarrGroup.create(OUT_PATH);
@@ -121,9 +129,13 @@ public static void main(String args[]) throws Exception {
                 dsname = "blosc/lz4"; // FIXME: better workaround?
             }
             Path subdir = OUT_PATH.resolve(dsname);
-            ZarrArray zArray = ZarrArray.create(subdir, arrayParams);
-            // final ZarrArray zarr = ZarrArray.open(getRootPath().resolve(pathName));
-            zArray.write(data, SHAPE, new int[]{0, 0, 0});
+            if (listOnly) {
+                System.out.println(OUT_PATH + "\t" + dsname);
+            } else {
+                ZarrArray zArray = ZarrArray.create(subdir, arrayParams);
+                // final ZarrArray zarr = ZarrArray.open(getRootPath().resolve(pathName));
+                zArray.write(data, SHAPE, new int[]{0, 0, 0});
+            }
         }
     }
 }
diff --git a/implementations/n5-java/driver.sh b/implementations/n5-java/driver.sh
new file mode 100755
index 00000000..912e111f
--- /dev/null
+++ b/implementations/n5-java/driver.sh
@@ -0,0 +1,40 @@
+#!/usr/bin/env bash
+ENVNAME=ZI_n5_java
+
+# Standard bootstrapping
+IMPL=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
+ROOT=$( dirname $IMPL)
+
+zi_write(){
+    create_or_activate
+
+    cd "${IMPL}"
+    MVN_FLAGS=${MVN_FLAGS:-"-q --no-transfer-progress"}
+    mvn ${MVN_FLAGS} package
+
+    java -cp target/n5_java-1.0.0.jar zarr_implementations.n5_java.App
+}
+
+zi_list(){
+    create_or_activate
+
+    cd "${IMPL}"
+    MVN_FLAGS=${MVN_FLAGS:-"-q --no-transfer-progress"}
+    mvn ${MVN_FLAGS} package
+
+    java -cp target/n5_java-1.0.0.jar zarr_implementations.n5_java.App -list
+}
+
+zi_read(){
+    create_or_activate
+
+    cd "${IMPL}"
+    MVN_FLAGS=${MVN_FLAGS:-"-q --no-transfer-progress"}
+    mvn ${MVN_FLAGS} package
+
+    java -cp target/n5_java-1.0.0.jar zarr_implementations.n5_java.App -verify "$@"
+}
+
+. $ROOT/.conda_driver.sh
+. $ROOT/.bash_driver.sh
+argparse "$@"
diff --git a/implementations/n5-java/environment.yml b/implementations/n5-java/environment.yml
new file mode 100644
index 00000000..a7a62cbb
--- /dev/null
+++ b/implementations/n5-java/environment.yml
@@ -0,0 +1,7 @@
+channels:
+  - conda-forge
+  - defaults
+dependencies:
+  - openjdk
+  - maven
+  - blosc
diff --git a/generate_data/n5-java/pom.xml b/implementations/n5-java/pom.xml
similarity index 100%
rename from generate_data/n5-java/pom.xml
rename to implementations/n5-java/pom.xml
diff --git a/generate_data/n5-java/src/main/java/zarr_implementations/n5_java/App.java b/implementations/n5-java/src/main/java/zarr_implementations/n5_java/App.java
similarity index 90%
rename from generate_data/n5-java/src/main/java/zarr_implementations/n5_java/App.java
rename to implementations/n5-java/src/main/java/zarr_implementations/n5_java/App.java
index bc6202c3..eea10f9d 100644
--- a/generate_data/n5-java/src/main/java/zarr_implementations/n5_java/App.java
+++ b/implementations/n5-java/src/main/java/zarr_implementations/n5_java/App.java
@@ -58,13 +58,18 @@ private static RandomAccessibleInterval<UnsignedByteType> getData() throws IOExc
 
 
 	public static void main(String args[]) throws IOException {
+		boolean listOnly = (args.length == 1 && args[0].equals("-list"));
 		RandomAccessibleInterval<UnsignedByteType> data = getData();
 		final N5FSWriter container = new N5FSWriter(OUT_PATH);
 		for (final Compression compression : getCompressions()) {
 			final DatasetAttributes attrs = new DatasetAttributes(Intervals.dimensionsAsLongArray(data), BLOCK_SIZE, DataType.UINT8, compression);
 			final String dataset = compression.getType();
-			container.createDataset(dataset, attrs);
-			N5Utils.save(data, container, dataset, BLOCK_SIZE, compression);
+			if (listOnly) {
+				System.out.println(OUT_PATH + "\t" + dataset);
+			} else {
+				container.createDataset(dataset, attrs);
+				N5Utils.save(data, container, dataset, BLOCK_SIZE, compression);
+			}
 		}
 	}
 
diff --git a/implementations/pyn5/.skip b/implementations/pyn5/.skip
new file mode 100644
index 00000000..bb855dd7
--- /dev/null
+++ b/implementations/pyn5/.skip
@@ -0,0 +1 @@
+pyn5 requires "n5" version attribute
diff --git a/implementations/pyn5/driver.sh b/implementations/pyn5/driver.sh
new file mode 100755
index 00000000..290d5a1a
--- /dev/null
+++ b/implementations/pyn5/driver.sh
@@ -0,0 +1,28 @@
+#!/usr/bin/env bash
+ENVNAME=ZI_pyn5
+
+# Standard bootstrapping
+IMPL=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
+ROOT=$( dirname $IMPL)
+
+zi_write(){
+    cd "${IMPL}"
+    create_or_activate
+    python $IMPL/generate_pyn5.py
+}
+
+zi_list(){
+    cd "${IMPL}"
+    create_or_activate
+    python $IMPL/generate_pyn5.py -list
+}
+
+zi_read(){
+    cd "${IMPL}"
+    create_or_activate
+    python $IMPL/generate_pyn5.py -verify "$@"
+}
+
+. $ROOT/.conda_driver.sh
+. $ROOT/.bash_driver.sh
+argparse "$@"
diff --git a/implementations/pyn5/environment.yml b/implementations/pyn5/environment.yml
new file mode 100644
index 00000000..44fbebf7
--- /dev/null
+++ b/implementations/pyn5/environment.yml
@@ -0,0 +1,11 @@
+channels:
+  - conda-forge
+  - defaults
+dependencies:
+  - rust
+  - maturin
+  - python
+  - scikit-image
+  - pip
+  - pip:
+      - "git+https://github.com/pattonw/rust-pyn5@master#egg=pyn5"
diff --git a/implementations/pyn5/generate_pyn5.py b/implementations/pyn5/generate_pyn5.py
new file mode 100755
index 00000000..f375b5d2
--- /dev/null
+++ b/implementations/pyn5/generate_pyn5.py
@@ -0,0 +1,41 @@
+#!/usr/bin/env python
+from pathlib import Path
+import pyn5
+from skimage.io import imread
+
+# choose chunks s.t. we do have overhanging edge-chunks
+CHUNKS = (100, 100, 1)
+
+
+def generate_n5_format(list_only: bool, compressors=pyn5.CompressionType):
+    data_dir = Path("../..") / "data"
+    path = data_dir / "pyn5.n5"
+
+    im = imread(data_dir / "reference_image.png")
+
+    f = pyn5.File(path, pyn5.Mode.CREATE_TRUNCATE)
+    for compressor in compressors:
+        name = str(compressor)
+        if list_only:
+            print(f"{path}\t{name}")
+        else:
+            f.create_dataset(name, data=im, chunks=CHUNKS, compression=compressor)
+
+
+def verify_format(directory: str, dataset: str):
+    f = pyn5.File(f"{directory}/{dataset}")# TODO, mode="r")
+    return f[:]
+
+
+if __name__ == '__main__':
+    import sys
+    import argparse
+    parser = argparse.ArgumentParser()
+    parser.add_argument("-list", action="store_true")
+    parser.add_argument("-verify", action="store_true")
+    parser.add_argument("args", nargs="*")
+    ns = parser.parse_args()
+    if ns.verify:
+        verify_format(*ns.args)
+    else:
+        generate_n5_format(ns.list)
diff --git a/implementations/tensorstore/.skip b/implementations/tensorstore/.skip
new file mode 100644
index 00000000..5b9a6bfa
--- /dev/null
+++ b/implementations/tensorstore/.skip
@@ -0,0 +1 @@
+compile issues
diff --git a/implementations/tensorstore/driver.sh b/implementations/tensorstore/driver.sh
new file mode 100755
index 00000000..2abbfc57
--- /dev/null
+++ b/implementations/tensorstore/driver.sh
@@ -0,0 +1,28 @@
+#!/usr/bin/env bash
+ENVNAME=ZI_tensorstore
+
+# Standard bootstrapping
+IMPL=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
+ROOT=$( dirname $IMPL)
+
+zi_write(){
+    cd "${IMPL}"
+    create_or_activate
+    python $IMPL/generate_tensorstore.py
+}
+
+zi_list(){
+    cd "${IMPL}"
+    create_or_activate
+    python $IMPL/generate_tensorstore.py -list
+}
+
+zi_read(){
+    cd "${IMPL}"
+    create_or_activate
+    python $IMPL/generate_tensorstore.py -verify "$@"
+}
+
+. $ROOT/.conda_driver.sh
+. $ROOT/.bash_driver.sh
+argparse "$@"
diff --git a/implementations/tensorstore/environment.yml b/implementations/tensorstore/environment.yml
new file mode 100644
index 00000000..a0ebaddc
--- /dev/null
+++ b/implementations/tensorstore/environment.yml
@@ -0,0 +1,10 @@
+channels:
+  - conda-forge
+dependencies:
+  - tensorstore
+  # Test generation
+  - numcodecs
+  - python
+  - scikit-image
+  - zarr
+  - fsspec
diff --git a/implementations/tensorstore/generate_tensorstore.py b/implementations/tensorstore/generate_tensorstore.py
new file mode 100755
index 00000000..b2e00e11
--- /dev/null
+++ b/implementations/tensorstore/generate_tensorstore.py
@@ -0,0 +1,121 @@
+#!/usr/bin/env python
+
+import tensorstore as ts
+import numcodecs
+from skimage.data import astronaut
+
+# choose chunks s.t. we do have overhanging edge-chunks
+CHUNKS = (100, 100, 1)
+STR_TO_COMPRESSOR = {
+    "gzip": numcodecs.GZip,
+    "blosc": numcodecs.Blosc,
+    "zlib": numcodecs.Zlib,
+}
+COMPRESSION_OPTIONS = {"blosc": {"cname": "lz4"}}
+
+im = astronaut()
+SIZE = im.shape
+
+
+def n5_metadata(compression: str):
+    return {
+        'compression': {
+            'type': compression,
+        },
+        'dataType': 'uint32',
+        'dimensions': SIZE,
+        'blockSize': CHUNKS,
+    }
+
+def zr_metadata():
+    if True:
+        chunk_grid = {"name": "regular", "configuration": {"chunk_shape": chunks}}  # read size
+
+        sharding_codec = {
+            "name": "sharding_indexed",
+            "configuration": {
+                "chunk_shape": chunks, # write size
+                "codecs": [{"name": "bytes", "configuration": {"endian": "little"}},
+                           {"name": "blosc", "configuration": {"cname": "zstd", "clevel": 5}}],
+                "index_codecs": [{"name": "bytes", "configuration": {"endian": "little"}},
+                                 {"name": "crc32c"}],
+                "index_location": "end"
+            }
+        }
+        codecs = [sharding_codec]
+    else:
+        # Alternative without sharding...
+        chunk_grid = {"name": "regular", "configuration": {"chunk_shape": chunks}}
+        blosc_codec = {"name": "blosc", "configuration": { "cname": "lz4", "clevel": 5}}
+        codecs = [blosc_codec]
+
+    base_config = {
+        "driver": "zarr3",
+        "kvstore": CONFIGS[1],
+        "metadata": {
+            "shape": shape,
+            "chunk_grid": chunk_grid,
+            "chunk_key_encoding": {"name": "default"}, # "configuration": {"separator": "/"}},
+            "codecs": codecs,
+            "data_type": read.dtype,
+            "dimension_names": dimension_names,
+        }
+    }
+
+
+def ts_write(driver: str, path: str, metadata: dict, data: List):
+    arr = ts.open({
+        'driver': driver,
+        'kvstore': {
+            'driver': 'file',
+            'path': path,
+        },
+        'metadata': metadata,
+        'create': True,
+        'delete_existing': True,
+    }).result()
+    write_future = arr.write(data)
+    write_future.result()
+
+
+# TODO use more compressors from numcodecs and more blosc filter_ids
+def generate_zarr_format(list_only:bool, compressors=['gzip', 'blosc', 'zlib', None]):
+    for compressor in compressors:
+        copts = COMPRESSION_OPTIONS.get(compressor, {})
+        if compressor is None:
+            name = "raw"
+        elif compressor == "blosc":
+            name = "%s/%s" % (compressor, copts.get("cname"))
+        else:
+            name = compressor
+        compressor_impl = STR_TO_COMPRESSOR[compressor](**copts) if compressor is not None else None
+        # V2. TODO: add method for v3 everywhere
+        if list_only:
+            print(f"data/tensorstore.zr\t{name}")
+        else:
+            ts_write('zarr', f'data/tensorstore.zr/{name}', zr_metadata(), im)
+
+
+def generate_n5_format(list_only:bool, compressors=['gzip', None]):
+    im = astronaut()
+    for compressor in compressors:
+        name = compressor if compressor is not None else 'raw'
+        compressor_impl = STR_TO_COMPRESSOR[compressor]() if compressor is not None else None
+        if list_only:
+            print(f"data/tensorstore.n5\t{name}")
+        else:
+            ts_write('zarr', f'data/tensorstore.n5/{name}', n5_metadata(), im)
+
+
+if __name__ == '__main__':
+    import argparse
+    parser = argparse.ArgumentParser()
+    parser.add_argument("-list", action="store_true")
+    parser.add_argument("-verify", action="store_true")
+    parser.add_argument("args", nargs="*")
+    ns = parser.parse_args()
+    if ns.verify:
+        verify_format(*ns.args)
+    else:
+        generate_zarr_format(ns.list)
+        generate_n5_format(ns.list)
diff --git a/implementations/xtensor_zarr/.gitignore b/implementations/xtensor_zarr/.gitignore
new file mode 100644
index 00000000..378eac25
--- /dev/null
+++ b/implementations/xtensor_zarr/.gitignore
@@ -0,0 +1 @@
+build
diff --git a/implementations/xtensor_zarr/.skip b/implementations/xtensor_zarr/.skip
new file mode 100644
index 00000000..3fa6019f
--- /dev/null
+++ b/implementations/xtensor_zarr/.skip
@@ -0,0 +1 @@
+no amd64; core dump on GH
diff --git a/generate_data/xtensor_zarr/CMakeLists.txt b/implementations/xtensor_zarr/CMakeLists.txt
similarity index 98%
rename from generate_data/xtensor_zarr/CMakeLists.txt
rename to implementations/xtensor_zarr/CMakeLists.txt
index 7ee11e5e..619eebaf 100644
--- a/generate_data/xtensor_zarr/CMakeLists.txt
+++ b/implementations/xtensor_zarr/CMakeLists.txt
@@ -1,7 +1,7 @@
 cmake_minimum_required(VERSION 3.8)
 
 if (CMAKE_CURRENT_SOURCE_DIR STREQUAL CMAKE_SOURCE_DIR)
-    project(generate_data)
+    project(implementations)
 
     find_package(xtensor-zarr REQUIRED CONFIG)
     set(XTENSOR_ZARR_INCLUDE_DIR ${xtensor_zarr_INCLUDE_DIRS})
diff --git a/implementations/xtensor_zarr/driver.sh b/implementations/xtensor_zarr/driver.sh
new file mode 100755
index 00000000..8cf4ea6b
--- /dev/null
+++ b/implementations/xtensor_zarr/driver.sh
@@ -0,0 +1,36 @@
+#!/usr/bin/env bash
+ENVNAME=ZI_xtensor_zarr
+
+# Standard bootstrapping
+IMPL=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
+ROOT=$( dirname $IMPL)
+
+zi_write(){
+    create_or_activate
+
+    cd "${IMPL}"
+
+    set +u # Due to GDAL_DATA
+
+    rm -rf build
+    mkdir build
+    cd build
+    export LDFLAGS="${LDFLAGS} -Wl,-rpath,$CONDA_PREFIX/lib -Wl,-rpath,$PWD"
+    export LINKFLAGS="${LDFLAGS}"
+    cmake .. -DCMAKE_PREFIX_PATH=$CONDA_PREFIX -DCMAKE_INSTALL_PREFIX=$CONDA_PREFIX -DCMAKE_INSTALL_LIBDIR=lib
+    make run
+}
+
+zi_list(){
+    echo "skipping list"
+    exit 1
+}
+
+zi_read(){
+    echo "skipping read"
+    exit 1
+}
+
+. $ROOT/.conda_driver.sh
+. $ROOT/.bash_driver.sh
+argparse "$@"
diff --git a/implementations/xtensor_zarr/environment.yml b/implementations/xtensor_zarr/environment.yml
new file mode 100644
index 00000000..a991ba1a
--- /dev/null
+++ b/implementations/xtensor_zarr/environment.yml
@@ -0,0 +1,9 @@
+channels:
+  - conda-forge
+  - defaults
+dependencies:
+  - python=3.8
+  - cmake
+  - xtensor-zarr>=0.0.7
+  - gdal>=3.0.4
+  - tbb=2020.2
diff --git a/generate_data/xtensor_zarr/modules/FindBlosc.cmake b/implementations/xtensor_zarr/modules/FindBlosc.cmake
similarity index 100%
rename from generate_data/xtensor_zarr/modules/FindBlosc.cmake
rename to implementations/xtensor_zarr/modules/FindBlosc.cmake
diff --git a/generate_data/xtensor_zarr/modules/FindOIIO.cmake b/implementations/xtensor_zarr/modules/FindOIIO.cmake
similarity index 100%
rename from generate_data/xtensor_zarr/modules/FindOIIO.cmake
rename to implementations/xtensor_zarr/modules/FindOIIO.cmake
diff --git a/generate_data/xtensor_zarr/src/main.cpp b/implementations/xtensor_zarr/src/main.cpp
similarity index 100%
rename from generate_data/xtensor_zarr/src/main.cpp
rename to implementations/xtensor_zarr/src/main.cpp
diff --git a/implementations/z5py/.skip b/implementations/z5py/.skip
new file mode 100644
index 00000000..6129b3da
--- /dev/null
+++ b/implementations/z5py/.skip
@@ -0,0 +1 @@
+read_metadata failure
diff --git a/implementations/z5py/driver.sh b/implementations/z5py/driver.sh
new file mode 100755
index 00000000..ffc9ae6f
--- /dev/null
+++ b/implementations/z5py/driver.sh
@@ -0,0 +1,28 @@
+#!/usr/bin/env bash
+ENVNAME=ZI_z5py
+
+# Standard bootstrapping
+IMPL=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
+ROOT=$( dirname $IMPL)
+
+zi_write(){
+    cd "${IMPL}"
+    create_or_activate
+    python $IMPL/generate_z5py.py
+}
+
+zi_list(){
+    cd "${IMPL}"
+    create_or_activate
+    python $IMPL/generate_z5py.py -list
+}
+
+zi_read(){
+    cd "${IMPL}"
+    create_or_activate
+    python $IMPL/generate_z5py.py -verify "$@"
+}
+
+. $ROOT/.conda_driver.sh
+. $ROOT/.bash_driver.sh
+argparse "$@"
diff --git a/implementations/z5py/environment.yml b/implementations/z5py/environment.yml
new file mode 100644
index 00000000..71cadd41
--- /dev/null
+++ b/implementations/z5py/environment.yml
@@ -0,0 +1,7 @@
+channels:
+  - conda-forge
+  - defaults
+dependencies:
+  - z5py
+  - python
+  - scikit-image
diff --git a/implementations/z5py/generate_z5py.py b/implementations/z5py/generate_z5py.py
new file mode 100644
index 00000000..3a40d61b
--- /dev/null
+++ b/implementations/z5py/generate_z5py.py
@@ -0,0 +1,63 @@
+#!/usr/bin/env python
+
+import z5py
+from skimage.data import astronaut
+
+# choose chunks s.t. we do have overhanging edge-chunks
+CHUNKS = (100, 100, 1)
+
+# options for the different compressors
+COMPRESSION_OPTIONS = {"blosc": {"codec": "lz4"}}
+
+
+# TODO support more compressors:
+# - more compressors in numcodecs
+# - more blosc codecs
+def generate_zarr_format(list_only:bool, compressors=['gzip', 'blosc', 'zlib', 'raw']):
+    path = '../../data/z5py.zr'
+    im = astronaut()
+
+    f = z5py.File(path, mode='w')
+    for compressor in compressors:
+        copts = COMPRESSION_OPTIONS.get(compressor, {})
+        name = (
+            compressor
+            if compressor != "blosc"
+            else "%s/%s" % (compressor, copts.get("codec"))
+        )
+        if list_only:
+            print(f"{path}\t{name}")
+        else:
+            f.create_dataset(name, data=im, compression=compressor, chunks=CHUNKS, **copts)
+
+
+def generate_n5_format(list_only:bool, compressors=['gzip', 'raw']):
+    path = '../../data/z5py.n5'
+    im = astronaut()
+
+    f = z5py.File(path, mode='w')
+    for compressor in compressors:
+        name = compressor
+        if list_only:
+            print(f"{path}\t{name}")
+        else:
+            f.create_dataset(name, data=im, chunks=CHUNKS, compression=compressor)
+
+
+def verify_format(directory: str, dataset: str):
+    f = z5py.File(f"{directory}/{dataset}", mode="r")
+    return f[:]
+
+
+if __name__ == '__main__':
+    import argparse
+    parser = argparse.ArgumentParser()
+    parser.add_argument("-list", action="store_true")
+    parser.add_argument("-verify", action="store_true")
+    parser.add_argument("args", nargs="*")
+    ns = parser.parse_args()
+    if ns.verify:
+        verify_format(*ns.args)
+    else:
+        generate_zarr_format(ns.list)
+        generate_n5_format(ns.list)
diff --git a/implementations/zarr-python/driver.sh b/implementations/zarr-python/driver.sh
new file mode 100755
index 00000000..5c98dc29
--- /dev/null
+++ b/implementations/zarr-python/driver.sh
@@ -0,0 +1,28 @@
+#!/usr/bin/env bash
+ENVNAME=ZI_zarr-python
+
+# Standard bootstrapping
+IMPL=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
+ROOT=$( dirname $IMPL)
+
+zi_write(){
+    cd "${IMPL}"
+    create_or_activate
+    python $IMPL/generate_zarr.py
+}
+
+zi_list(){
+    cd "${IMPL}"
+    create_or_activate
+    python $IMPL/generate_zarr.py -list
+}
+
+zi_read(){
+    cd "${IMPL}"
+    create_or_activate
+    python $IMPL/generate_zarr.py -verify "$@"
+}
+
+. $ROOT/.conda_driver.sh
+. $ROOT/.bash_driver.sh
+argparse "$@"
diff --git a/implementations/zarr-python/environment.yml b/implementations/zarr-python/environment.yml
new file mode 100644
index 00000000..1fd13515
--- /dev/null
+++ b/implementations/zarr-python/environment.yml
@@ -0,0 +1,8 @@
+channels:
+  - conda-forge
+  - defaults
+dependencies:
+  - python
+  - scikit-image
+  - zarr
+  - fsspec
diff --git a/generate_data/generate_zarr.py b/implementations/zarr-python/generate_zarr.py
similarity index 61%
rename from generate_data/generate_zarr.py
rename to implementations/zarr-python/generate_zarr.py
index a0e0c4ca..b3b81ec4 100644
--- a/generate_data/generate_zarr.py
+++ b/implementations/zarr-python/generate_zarr.py
@@ -1,3 +1,5 @@
+#!/usr/bin/env python
+
 import zarr
 import numcodecs
 from skimage.data import astronaut
@@ -13,7 +15,7 @@
 
 
 # TODO use more compressors from numcodecs and more blosc filter_ids
-def generate_zarr_format(compressors=['gzip', 'blosc', 'zlib', None]):
+def generate_zarr_format(list_only:bool, compressors=['gzip', 'blosc', 'zlib', None]):
 
     for nested, StoreClass, store_kwargs in [
         (False, zarr.storage.DirectoryStore, {}),
@@ -24,7 +26,7 @@ def generate_zarr_format(compressors=['gzip', 'blosc', 'zlib', None]):
     ]:
 
         nested_str = '_nested' if nested else '_flat'
-        path = f'data/zarr_{StoreClass.__name__}{nested_str}.zr'
+        path = f'../../data/zarr_{StoreClass.__name__}{nested_str}.zr'
         store = StoreClass(path, **store_kwargs)
         im = astronaut()
 
@@ -38,21 +40,41 @@ def generate_zarr_format(compressors=['gzip', 'blosc', 'zlib', None]):
             else:
                 name = compressor
             compressor_impl = STR_TO_COMPRESSOR[compressor](**copts) if compressor is not None else None
-            f.create_dataset(name, data=im, chunks=CHUNKS,
-                             compressor=compressor_impl)
+            if list_only:
+                print(f"{path}\t{name}")
+            else:
+                f.create_dataset(name, data=im, chunks=CHUNKS,
+                                 compressor=compressor_impl)
 
 
-def generate_n5_format(compressors=['gzip', None]):
+def generate_n5_format(list_only:bool, compressors=['gzip', None]):
     im = astronaut()
 
-    f = zarr.open('data/zarr.n5', mode='w')
+    path = "../../data/zarr.n5"
+    f = zarr.open(path, mode='w')
     for compressor in compressors:
         name = compressor if compressor is not None else 'raw'
         compressor_impl = STR_TO_COMPRESSOR[compressor]() if compressor is not None else None
-        f.create_dataset(name, data=im, chunks=CHUNKS,
-                         compressor=compressor_impl)
+        if list_only:
+            print(f"{path}\t{name}")
+        else:
+            f.create_dataset(name, data=im, chunks=CHUNKS,
+                             compressor=compressor_impl)
+
+
+def verify_format(path: str, group: str):
+    print(path, group)
 
 
 if __name__ == '__main__':
-    generate_zarr_format()
-    generate_n5_format()
+    import argparse
+    parser = argparse.ArgumentParser()
+    parser.add_argument("-list", action="store_true")
+    parser.add_argument("-verify", action="store_true")
+    parser.add_argument("args", nargs="*")
+    ns = parser.parse_args()
+    if ns.verify:
+        verify_format(*ns.args)
+    else:
+        generate_zarr_format(ns.list)
+        generate_n5_format(ns.list)
diff --git a/implementations/zarrita/driver.sh b/implementations/zarrita/driver.sh
new file mode 100755
index 00000000..480b393d
--- /dev/null
+++ b/implementations/zarrita/driver.sh
@@ -0,0 +1,28 @@
+#!/usr/bin/env bash
+ENVNAME=ZI_zarrita
+
+# Standard bootstrapping
+IMPL=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
+ROOT=$( dirname $IMPL)
+
+zi_write(){
+    cd "${IMPL}"
+    create_or_activate
+    python $IMPL/generate_zarrita.py
+}
+
+zi_list(){
+    cd "${IMPL}"
+    create_or_activate
+    python $IMPL/generate_zarrita.py -list
+}
+
+zi_read(){
+    cd "${IMPL}"
+    create_or_activate
+    python $IMPL/generate_zarrita.py -verify "$@"
+}
+
+. $ROOT/.conda_driver.sh
+. $ROOT/.bash_driver.sh
+argparse "$@"
diff --git a/implementations/zarrita/environment.yml b/implementations/zarrita/environment.yml
new file mode 100644
index 00000000..66901648
--- /dev/null
+++ b/implementations/zarrita/environment.yml
@@ -0,0 +1,9 @@
+channels:
+  - conda-forge
+  - defaults
+dependencies:
+  - python
+  - pip
+  - pip:
+      - scikit-image
+      - zarrita
diff --git a/implementations/zarrita/generate_zarrita.py b/implementations/zarrita/generate_zarrita.py
new file mode 100644
index 00000000..5ed76c9c
--- /dev/null
+++ b/implementations/zarrita/generate_zarrita.py
@@ -0,0 +1,75 @@
+#!/usr/bin/env python
+
+import zarrita
+from skimage.data import astronaut
+
+# choose chunks s.t. we do have overhanging edge-chunks
+CHUNK_SHAPE = (100, 100, 1)
+SHARD_SHAPE = (1000, 1000, 3)
+STR_TO_CODEC = {
+    "gzip": zarrita.codecs.gzip_codec(),
+    "blosc": zarrita.codecs.blosc_codec(cname="lz4", typesize=10),
+}
+
+
+def generate_zr3_format(list_only:bool, codecs=["gzip", "blosc", None], nested=True, sharded=True):
+    im = astronaut()
+    fname = "zarrita"
+    if nested:
+        chunk_separator = "/"
+        fname += "_nested"
+    else:
+        chunk_separator = "."
+    if sharded:
+        fname += "_sharded"
+
+    path = f"../../data/{fname}"
+    store = zarrita.LocalStore(path)
+    g = zarrita.Group.create(store, exists_ok=True)
+    for codec in codecs:
+        if codec is None:
+            name = "raw"
+        elif codec == "blosc":
+            name = f"{codec}/{STR_TO_CODEC[codec].configuration.cname}"
+        else:
+            name = codec
+
+        codecs_impl = [zarrita.codecs.bytes_codec()]
+        if codec is not None:
+            codecs_impl.append(STR_TO_CODEC[codec])
+
+        if sharded:
+            codecs_impl = [
+                zarrita.codecs.sharding_codec(
+                    chunk_shape=CHUNK_SHAPE, codecs=codecs_impl
+                ),
+            ]
+
+        if list_only:
+            print(f"{path}\t{name}")
+        else:
+            a = g.create_array(
+                name,
+                shape=im.shape,
+                chunk_shape=SHARD_SHAPE if sharded else CHUNK_SHAPE,
+                chunk_key_encoding=("default", chunk_separator),
+                dtype=im.dtype,
+                codecs=codecs_impl,
+                exists_ok=True,
+            )
+            a[:, :, :]= im
+
+
+if __name__ == "__main__":
+    import argparse
+    parser = argparse.ArgumentParser()
+    parser.add_argument("-list", action="store_true")
+    parser.add_argument("-verify", action="store_true")
+    parser.add_argument("args", nargs="*")
+    ns = parser.parse_args()
+    if ns.verify:
+        verify_format(*ns.args)
+    else:
+        for nested in [False, True]:
+            for sharded in [False, True]:
+                generate_zr3_format(ns.list, nested=nested, sharded=sharded)
diff --git a/test/test_read_all.py b/test/test_read_all.py
index c8e77049..8f740c93 100644
--- a/test/test_read_all.py
+++ b/test/test_read_all.py
@@ -1,3 +1,4 @@
+#!/usr/bin/env python
 """
 Usage
 =====
@@ -33,6 +34,7 @@
 
 """
 import os
+import sys
 import subprocess
 from typing import Dict, List
 from pathlib import Path
@@ -73,72 +75,71 @@
         "zarr-v3": ["blosc", "gzip", "raw", "zlib"],
         "N5": [],
     },
+    "Rarr": {
+        "zarr": ["blosc", "gzip", "raw", "zlib"],
+        "zarr-v3": [],
+        "N5": [],
+    },
 }
 
 
-def read_with_jzarr(fpath, ds_name, nested=None):
-    if ds_name == "blosc":
-        ds_name = "blosc/lz4"
-
+def make_read(name, fpath, ds_name, nested=None):
     cmd = (
-        f"generate_data/jzarr/generate_data.sh "
-        f"-verify {str(fpath)} {ds_name}"
+        f"make implementations/{name}-read-fast "
+        f"NODEBUG=1 DIR={str(fpath)} DATASET={ds_name}"
     )
 
     # will raise subprocess.CalledProcessError if return code is not 0
-    subprocess.check_output(cmd, shell=True)
-    return None
+    result = subprocess.run(cmd, shell=True,
+                            stdout=subprocess.PIPE,
+                            stderr=subprocess.PIPE)
+    if result.returncode != 0:
+        raise Exception(
+            {
+                "command": cmd,
+                "stdout": result.stdout,
+                "stderr": result.stderr,
+            }
+        )
+    return result
+
+def read_with_jzarr(fpath, ds_name, nested=None):
+    if ds_name == "blosc":
+        ds_name = "blosc/lz4"
+    return make_read("jzarr", fpath, ds_name, nested)
 
 
 def read_with_zarr(fpath, ds_name, nested):
-    import zarr
     if ds_name == "blosc":
         ds_name = "blosc/lz4"
-    if str(fpath).endswith('.zr'):
-        if nested:
-            if 'FSStore' in str(fpath):
-                store = zarr.storage.FSStore(
-                    os.fspath(fpath), dimension_separator='/', mode='r'
-                )
-            else:
-                store = zarr.storage.NestedDirectoryStore(os.fspath(fpath))
-        else:
-            if 'FSStore' in str(fpath):
-                store = zarr.storage.FSStore(os.fspath(fpath))
-            else:
-                store = zarr.storage.DirectoryStore(fpath)
-    else:
-        store = os.fspath(fpath)
-    return zarr.open(store)[ds_name][:]
+    return make_read("zarr-python", fpath, ds_name, nested)
 
 
 def read_with_pyn5(fpath, ds_name, nested):
-    import pyn5
-    return pyn5.File(fpath)[ds_name][:]
+    return make_read("pyn5", fpath, ds_name, nested)
 
 
 def read_with_z5py(fpath, ds_name, nested):
-    import z5py
     if ds_name == "blosc":
         ds_name = "blosc/lz4"
-    return z5py.File(fpath)[ds_name][:]
+    return make_read("z5py", fpath, ds_name, nested)
 
 
 def read_with_zarrita(fpath, ds_name, nested):
-    import zarrita
     if ds_name == "blosc":
         ds_name = "blosc/lz4"
-    h = zarrita.get_hierarchy(str(fpath.absolute()))
-    return h["/" + ds_name][:]
+    return make_read("zarrita", fpath, ds_name, nested)
 
 def read_with_xtensor_zarr(fpath, ds_name, nested):
+     if ds_name == "blosc":
+        ds_name = "blosc/lz4"
+     return make_read("xtensor_zarr", fpath, ds_name, nested)
+
+def read_with_Rarr(fpath, ds_name, nested):
+
     if ds_name == "blosc":
         ds_name = "blosc/lz4"
-    fname = "a.npz"
-    if os.path.exists(fname):
-        os.remove(fname)
-    subprocess.check_call(["generate_data/xtensor_zarr/build/run_xtensor_zarr", fpath, ds_name])
-    return np.load(fname)["a"]
+    return make_read("Rarr", fpath, ds_name, nested)
 
 
 EXTENSIONS = {"zarr": ".zr", "N5": ".n5", "zarr-v3": ".zr3"}
@@ -220,8 +221,8 @@ def create_params():
                     if write_attrs:
                         write_attrs = ' (' + write_attrs + ')'
                     ids.append(
-                        f"read {writing_library}{write_attrs} {fmt} using "
-                        f"{reading_library}, {codec}"
+                        f"W-{writing_library}{write_attrs} {fmt}_R-"
+                        f"{reading_library}_{codec}"
                     )
     return argnames, params, ids
 
@@ -237,6 +238,7 @@ def _get_read_fn(reading_library):
         "z5py": read_with_z5py,
         "zarrita": read_with_zarrita,
         "xtensor_zarr": read_with_xtensor_zarr,
+        "Rarr": read_with_Rarr,
     }[reading_library]
     return read_fn
 
@@ -254,11 +256,13 @@ def test_correct_read(fmt, writing_library, reading_library, codec, nested,
             f"file not found: {fpath}. Make sure you have generated the data "
             "using 'make data'"
         )
-    test = read_fn(fpath, codec, nested)
-    # Assume if None is returned, the read function has verified.
-    if test is not None:
-        assert test.shape == reference.shape
-        assert np.allclose(test, reference)
+    result = read_fn(fpath, codec, nested)
+
+    if b"Skipping" in result.stderr:
+        pytest.skip(result.stderr.decode())
+    else:
+        print(result.stdout)
+        print(result.stderr, file=sys.stderr)
 
 
 def tabulate_test_results(params, per_codec_tables=False):