diff --git a/.github/workflows/gradle.yml b/.github/workflows/gradle.yml
new file mode 100644
index 00000000..adc74adf
--- /dev/null
+++ b/.github/workflows/gradle.yml
@@ -0,0 +1,17 @@
+name: Gradle build
+
+on: [push]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v1
+    - name: Set up JDK 11
+      uses: actions/setup-java@v1
+      with:
+        java-version: 11
+    - name: Build with Gradle
+      run: ./gradlew build
diff --git a/README.md b/README.md
index 79fa4cf1..b712501c 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 
-
+[![DOI](https://zenodo.org/badge/148831678.svg)](https://zenodo.org/badge/latestdoi/148831678)
 
 # Questions and Answers #
 
diff --git a/build.gradle.kts b/build.gradle.kts
index 7f190853..cf2f4387 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -1,12 +1,12 @@
 import scientifik.ScientifikExtension
 
 plugins {
-    id("scientifik.mpp") version "0.2.2" apply false
-    id("scientifik.jvm") version "0.2.2" apply false
-    id("scientifik.publish") version "0.2.2" apply false
+    id("scientifik.mpp") version "0.2.4" apply false
+    id("scientifik.jvm") version "0.2.4" apply false
+    id("scientifik.publish") version "0.2.4" apply false
 }
 
-val dataforgeVersion by extra("0.1.5-dev-2")
+val dataforgeVersion by extra("0.1.5-dev-3")
 
 val bintrayRepo by extra("dataforge")
 val githubProject by extra("dataforge-core")
diff --git a/dataforge-data/src/commonMain/kotlin/hep/dataforge/data/DataNode.kt b/dataforge-data/src/commonMain/kotlin/hep/dataforge/data/DataNode.kt
index 65c07676..a673f0b7 100644
--- a/dataforge-data/src/commonMain/kotlin/hep/dataforge/data/DataNode.kt
+++ b/dataforge-data/src/commonMain/kotlin/hep/dataforge/data/DataNode.kt
@@ -15,20 +15,20 @@ sealed class DataItem<out T : Any> : MetaRepr {
 
     abstract val meta: Meta
 
-    class Node<out T : Any>(val value: DataNode<T>) : DataItem<T>() {
-        override val type: KClass<out T> get() = value.type
+    class Node<out T : Any>(val node: DataNode<T>) : DataItem<T>() {
+        override val type: KClass<out T> get() = node.type
 
-        override fun toMeta(): Meta = value.toMeta()
+        override fun toMeta(): Meta = node.toMeta()
 
-        override val meta: Meta get() = value.meta
+        override val meta: Meta get() = node.meta
     }
 
-    class Leaf<out T : Any>(val value: Data<T>) : DataItem<T>() {
-        override val type: KClass<out T> get() = value.type
+    class Leaf<out T : Any>(val data: Data<T>) : DataItem<T>() {
+        override val type: KClass<out T> get() = data.type
 
-        override fun toMeta(): Meta = value.toMeta()
+        override fun toMeta(): Meta = data.toMeta()
 
-        override val meta: Meta get() = value.meta
+        override val meta: Meta get() = data.meta
     }
 }
 
@@ -68,8 +68,8 @@ interface DataNode<out T : Any> : MetaRepr {
     }
 }
 
-val <T : Any> DataItem<T>?.node: DataNode<T>? get() = (this as? DataItem.Node<T>)?.value
-val <T : Any> DataItem<T>?.data: Data<T>? get() = (this as? DataItem.Leaf<T>)?.value
+val <T : Any> DataItem<T>?.node: DataNode<T>? get() = (this as? DataItem.Node<T>)?.node
+val <T : Any> DataItem<T>?.data: Data<T>? get() = (this as? DataItem.Leaf<T>)?.data
 
 /**
  * Start computation for all goals in data node and return a job for the whole node
@@ -77,8 +77,8 @@ val <T : Any> DataItem<T>?.data: Data<T>? get() = (this as? DataItem.Leaf<T>)?.v
 fun DataNode<*>.launchAll(scope: CoroutineScope): Job = scope.launch {
     items.values.forEach {
         when (it) {
-            is DataItem.Node<*> -> it.value.launchAll(scope)
-            is DataItem.Leaf<*> -> it.value.start(scope)
+            is DataItem.Node<*> -> it.node.launchAll(scope)
+            is DataItem.Leaf<*> -> it.data.start(scope)
         }
     }
 }
@@ -98,7 +98,7 @@ fun <T : Any> DataNode<T>.asSequence(): Sequence<Pair<Name, DataItem<T>>> = sequ
     items.forEach { (head, item) ->
         yield(head.asName() to item)
         if (item is DataItem.Node) {
-            val subSequence = item.value.asSequence()
+            val subSequence = item.node.asSequence()
                 .map { (name, data) -> (head.asName() + name) to data }
             yieldAll(subSequence)
         }
@@ -111,9 +111,9 @@ fun <T : Any> DataNode<T>.asSequence(): Sequence<Pair<Name, DataItem<T>>> = sequ
 fun <T : Any> DataNode<T>.dataSequence(): Sequence<Pair<Name, Data<T>>> = sequence {
     items.forEach { (head, item) ->
         when (item) {
-            is DataItem.Leaf -> yield(head.asName() to item.value)
+            is DataItem.Leaf -> yield(head.asName() to item.data)
             is DataItem.Node -> {
-                val subSequence = item.value.dataSequence()
+                val subSequence = item.node.dataSequence()
                     .map { (name, data) -> (head.asName() + name) to data }
                 yieldAll(subSequence)
             }
@@ -188,8 +188,8 @@ class DataTreeBuilder<T : Any>(val type: KClass<out T>) {
     operator fun set(name: Name, node: DataNode<T>) = set(name, node.builder())
 
     operator fun set(name: Name, item: DataItem<T>) = when (item) {
-        is DataItem.Node<T> -> set(name, item.value.builder())
-        is DataItem.Leaf<T> -> set(name, item.value)
+        is DataItem.Node<T> -> set(name, item.node.builder())
+        is DataItem.Leaf<T> -> set(name, item.data)
     }
 
     /**
@@ -223,6 +223,10 @@ class DataTreeBuilder<T : Any>(val type: KClass<out T>) {
 
     fun meta(block: MetaBuilder.() -> Unit) = meta.apply(block)
 
+    fun meta(meta: Meta) {
+        this.meta = meta.builder()
+    }
+
     fun build(): DataTree<T> {
         val resMap = map.mapValues { (_, value) ->
             when (value) {
diff --git a/dataforge-data/src/commonMain/kotlin/hep/dataforge/data/dataCast.kt b/dataforge-data/src/commonMain/kotlin/hep/dataforge/data/dataCast.kt
index 0b9a4910..2bf8adde 100644
--- a/dataforge-data/src/commonMain/kotlin/hep/dataforge/data/dataCast.kt
+++ b/dataforge-data/src/commonMain/kotlin/hep/dataforge/data/dataCast.kt
@@ -28,8 +28,8 @@ expect fun <R : Any> DataNode<*>.canCast(type: KClass<out R>): Boolean
 expect fun <R : Any> Data<*>.canCast(type: KClass<out R>): Boolean
 
 fun <R : Any> DataItem<*>.canCast(type: KClass<out R>): Boolean = when (this) {
-    is DataItem.Node -> value.canCast(type)
-    is DataItem.Leaf -> value.canCast(type)
+    is DataItem.Node -> node.canCast(type)
+    is DataItem.Leaf -> data.canCast(type)
 }
 
 /**
diff --git a/dataforge-data/src/jvmMain/kotlin/hep/dataforge/data/TypeFilteredDataNode.kt b/dataforge-data/src/jvmMain/kotlin/hep/dataforge/data/TypeFilteredDataNode.kt
index 331f3b0e..3590679c 100644
--- a/dataforge-data/src/jvmMain/kotlin/hep/dataforge/data/TypeFilteredDataNode.kt
+++ b/dataforge-data/src/jvmMain/kotlin/hep/dataforge/data/TypeFilteredDataNode.kt
@@ -14,12 +14,12 @@ class TypeFilteredDataNode<out T : Any>(val origin: DataNode<*>, override val ty
         origin.items.mapNotNull { (key, item) ->
             when (item) {
                 is DataItem.Leaf -> {
-                    (item.value.filterIsInstance(type))?.let {
+                    (item.data.filterIsInstance(type))?.let {
                         key to DataItem.Leaf(it)
                     }
                 }
                 is DataItem.Node -> {
-                    key to DataItem.Node(item.value.filterIsInstance(type))
+                    key to DataItem.Node(item.node.filterIsInstance(type))
                 }
             }
         }.associate { it }
diff --git a/dataforge-data/src/jvmMain/kotlin/hep/dataforge/data/dataJVM.kt b/dataforge-data/src/jvmMain/kotlin/hep/dataforge/data/dataJVM.kt
index 29d048ed..f354c2f7 100644
--- a/dataforge-data/src/jvmMain/kotlin/hep/dataforge/data/dataJVM.kt
+++ b/dataforge-data/src/jvmMain/kotlin/hep/dataforge/data/dataJVM.kt
@@ -42,8 +42,8 @@ fun <R : Any> DataNode<*>.filterIsInstance(type: KClass<out R>): DataNode<R> {
  */
 fun <R : Any> DataItem<*>?.filterIsInstance(type: KClass<out R>): DataItem<R>? = when (this) {
     null -> null
-    is DataItem.Node -> DataItem.Node(this.value.filterIsInstance(type))
-    is DataItem.Leaf -> this.value.filterIsInstance(type)?.let { DataItem.Leaf(it) }
+    is DataItem.Node -> DataItem.Node(this.node.filterIsInstance(type))
+    is DataItem.Leaf -> this.data.filterIsInstance(type)?.let { DataItem.Leaf(it) }
 }
 
 inline fun <reified R : Any> DataItem<*>?.filterIsInstance(): DataItem<R>? = this@filterIsInstance.filterIsInstance(R::class)
\ No newline at end of file
diff --git a/dataforge-io/dataforge-io-yaml/build.gradle.kts b/dataforge-io/dataforge-io-yaml/build.gradle.kts
index 74ba43cf..d287d9ac 100644
--- a/dataforge-io/dataforge-io-yaml/build.gradle.kts
+++ b/dataforge-io/dataforge-io-yaml/build.gradle.kts
@@ -7,6 +7,4 @@ description = "YAML meta IO"
 dependencies {
     api(project(":dataforge-io"))
     api("org.yaml:snakeyaml:1.25")
-    testImplementation(kotlin("test"))
-    testImplementation(kotlin("test-junit"))
 }
diff --git a/dataforge-io/dataforge-io-yaml/src/test/kotlin/hep/dataforge/io/yaml/YamlMetaFormatTest.kt b/dataforge-io/dataforge-io-yaml/src/test/kotlin/hep/dataforge/io/yaml/YamlMetaFormatTest.kt
index 414162f7..5c5b3c18 100644
--- a/dataforge-io/dataforge-io-yaml/src/test/kotlin/hep/dataforge/io/yaml/YamlMetaFormatTest.kt
+++ b/dataforge-io/dataforge-io-yaml/src/test/kotlin/hep/dataforge/io/yaml/YamlMetaFormatTest.kt
@@ -6,7 +6,7 @@ import hep.dataforge.meta.Meta
 import hep.dataforge.meta.buildMeta
 import hep.dataforge.meta.get
 import hep.dataforge.meta.seal
-import org.junit.Test
+import org.junit.jupiter.api.Test
 import kotlin.test.assertEquals
 
 
diff --git a/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/Binary.kt b/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/Binary.kt
index bd1f2249..b671928b 100644
--- a/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/Binary.kt
+++ b/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/Binary.kt
@@ -10,7 +10,7 @@ interface Binary {
     /**
      * The size of binary in bytes. [ULong.MAX_VALUE] if size is not defined and input should be read until its end is reached
      */
-    val size: ULong
+    val size: ULong get() = ULong.MAX_VALUE
 
     /**
      * Read continuous [Input] from this binary stating from the beginning.
@@ -41,7 +41,11 @@ interface RandomAccessBinary : Binary {
 }
 
 fun Binary.toBytes(): ByteArray = read {
-    this.readBytes()
+    readBytes()
+}
+
+fun Binary.contentToString(): String = read {
+    readText()
 }
 
 @ExperimentalUnsignedTypes
diff --git a/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/Envelope.kt b/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/Envelope.kt
index 7cb918df..abf8a504 100644
--- a/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/Envelope.kt
+++ b/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/Envelope.kt
@@ -83,4 +83,3 @@ fun Envelope.withMetaLayers(vararg layers: Meta): Envelope {
         else -> ProxyEnvelope(this, *layers)
     }
 }
-
diff --git a/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/EnvelopeFormat.kt b/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/EnvelopeFormat.kt
index 4f747ea2..49a25919 100644
--- a/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/EnvelopeFormat.kt
+++ b/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/EnvelopeFormat.kt
@@ -23,11 +23,15 @@ interface EnvelopeFormat : IOFormat<Envelope> {
 
     fun Input.readPartial(): PartialEnvelope
 
-    fun Output.writeEnvelope(envelope: Envelope, metaFormatFactory: MetaFormatFactory, formatMeta: Meta = EmptyMeta)
+    fun Output.writeEnvelope(
+        envelope: Envelope,
+        metaFormatFactory: MetaFormatFactory = defaultMetaFormat,
+        formatMeta: Meta = EmptyMeta
+    )
 
     override fun Input.readObject(): Envelope
 
-    override fun Output.writeObject(obj: Envelope): Unit = writeEnvelope(obj, defaultMetaFormat)
+    override fun Output.writeObject(obj: Envelope): Unit = writeEnvelope(obj)
 }
 
 @Type(ENVELOPE_FORMAT_TYPE)
diff --git a/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/EnvelopeParts.kt b/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/EnvelopeParts.kt
index eb1dd696..d1b86195 100644
--- a/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/EnvelopeParts.kt
+++ b/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/EnvelopeParts.kt
@@ -3,6 +3,7 @@ package hep.dataforge.io
 import hep.dataforge.context.Global
 import hep.dataforge.io.EnvelopeParts.FORMAT_META_KEY
 import hep.dataforge.io.EnvelopeParts.FORMAT_NAME_KEY
+import hep.dataforge.io.EnvelopeParts.INDEX_KEY
 import hep.dataforge.io.EnvelopeParts.MULTIPART_DATA_TYPE
 import hep.dataforge.io.EnvelopeParts.SIZE_KEY
 import hep.dataforge.meta.*
@@ -13,6 +14,7 @@ import hep.dataforge.names.toName
 object EnvelopeParts {
     val MULTIPART_KEY = "multipart".asName()
     val SIZE_KEY = Envelope.ENVELOPE_NODE_KEY + MULTIPART_KEY + "size"
+    val INDEX_KEY = Envelope.ENVELOPE_NODE_KEY + MULTIPART_KEY + "index"
     val FORMAT_NAME_KEY = Envelope.ENVELOPE_NODE_KEY + MULTIPART_KEY + "format"
     val FORMAT_META_KEY = Envelope.ENVELOPE_NODE_KEY + MULTIPART_KEY + "meta"
 
@@ -37,8 +39,37 @@ fun EnvelopeBuilder.multipart(format: EnvelopeFormatFactory, envelopes: Collecti
     }
 }
 
-fun EnvelopeBuilder.multipart(formatFactory: EnvelopeFormatFactory, builder: suspend SequenceScope<Envelope>.() -> Unit) =
-    multipart(formatFactory, sequence(builder).toList())
+/**
+ * Create a multipart partition in the envelope adding additional name-index mapping in meta
+ */
+@DFExperimental
+fun EnvelopeBuilder.multipart(format: EnvelopeFormatFactory, envelopes: Map<String, Envelope>) {
+    dataType = MULTIPART_DATA_TYPE
+    meta {
+        SIZE_KEY put envelopes.size
+        FORMAT_NAME_KEY put format.name.toString()
+    }
+    data {
+        format.run {
+            var counter = 0
+            envelopes.forEach {(key, envelope)->
+                writeObject(envelope)
+                meta{
+                    append(INDEX_KEY, buildMeta {
+                        "key" put key
+                        "index" put counter
+                    })
+                }
+                counter++
+            }
+        }
+    }
+}
+
+fun EnvelopeBuilder.multipart(
+    formatFactory: EnvelopeFormatFactory,
+    builder: suspend SequenceScope<Envelope>.() -> Unit
+) = multipart(formatFactory, sequence(builder).toList())
 
 /**
  * If given envelope supports multipart data, return a sequence of those parts (could be empty). Otherwise return null.
diff --git a/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/IOFormat.kt b/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/IOFormat.kt
index bd1e54f4..e5497365 100644
--- a/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/IOFormat.kt
+++ b/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/IOFormat.kt
@@ -79,8 +79,10 @@ inline fun buildPacketWithoutPool(headerSizeHint: Int = 0, block: BytePacketBuil
 }
 
 fun <T : Any> IOFormat<T>.writePacket(obj: T): ByteReadPacket = buildPacket { writeObject(obj) }
-//TODO Double buffer copy. fix all that with IO-2
+
+@Deprecated("Not to be used outside tests due to double buffer write")
 fun <T : Any> IOFormat<T>.writeBytes(obj: T): ByteArray = buildPacket { writeObject(obj) }.readBytes()
+@Deprecated("Not to be used outside tests due to double buffer write")
 fun <T : Any> IOFormat<T>.readBytes(array: ByteArray): T = buildPacket { writeFully(array) }.readObject()
 
 object DoubleIOFormat : IOFormat<Double>, IOFormatFactory<Double> {
diff --git a/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/IOPlugin.kt b/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/IOPlugin.kt
index ae88e4f4..eb975029 100644
--- a/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/IOPlugin.kt
+++ b/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/IOPlugin.kt
@@ -20,7 +20,7 @@ class IOPlugin(meta: Meta) : AbstractPlugin(meta) {
         metaFormatFactories.find { it.key == key }?.invoke(meta)
 
     fun metaFormat(name: String, meta: Meta = EmptyMeta): MetaFormat? =
-        metaFormatFactories.find { it.name.toString() == name }?.invoke(meta)
+        metaFormatFactories.find { it.name.last().toString() == name }?.invoke(meta)
 
     val envelopeFormatFactories by lazy {
         context.content<EnvelopeFormatFactory>(ENVELOPE_FORMAT_TYPE).values
@@ -52,7 +52,7 @@ class IOPlugin(meta: Meta) : AbstractPlugin(meta) {
 
     companion object : PluginFactory<IOPlugin> {
         val defaultMetaFormats: List<MetaFormatFactory> = listOf(JsonMetaFormat, BinaryMetaFormat)
-        val defaultEnvelopeFormats = listOf(TaggedEnvelopeFormat)
+        val defaultEnvelopeFormats = listOf(TaggedEnvelopeFormat, TaglessEnvelopeFormat)
 
         override val tag: PluginTag = PluginTag("io", group = PluginTag.DATAFORGE_GROUP)
 
diff --git a/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/TaggedEnvelopeFormat.kt b/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/TaggedEnvelopeFormat.kt
index a95b7bfb..a461d257 100644
--- a/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/TaggedEnvelopeFormat.kt
+++ b/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/TaggedEnvelopeFormat.kt
@@ -38,15 +38,15 @@ class TaggedEnvelopeFormat(
 
     override fun Output.writeEnvelope(envelope: Envelope, metaFormatFactory: MetaFormatFactory, formatMeta: Meta) {
         val metaFormat = metaFormatFactory.invoke(formatMeta, io.context)
-        val metaBytes = metaFormat.writeBytes(envelope.meta)
+        val metaBytes = metaFormat.writePacket(envelope.meta)
         val actualSize: ULong = if (envelope.data == null) {
             0u
         } else {
             envelope.data?.size ?: ULong.MAX_VALUE
         }
-        val tag = Tag(metaFormatFactory.key, metaBytes.size.toUInt() + 2u, actualSize)
+        val tag = Tag(metaFormatFactory.key, metaBytes.remaining.toUInt() + 2u, actualSize)
         writePacket(tag.toBytes())
-        writeFully(metaBytes)
+        writePacket(metaBytes)
         writeText("\r\n")
         envelope.data?.read { copyTo(this@writeEnvelope) }
         flush()
diff --git a/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/TaglessEnvelopeFormat.kt b/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/TaglessEnvelopeFormat.kt
index a8f84be0..1cc62a2b 100644
--- a/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/TaglessEnvelopeFormat.kt
+++ b/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/TaglessEnvelopeFormat.kt
@@ -37,10 +37,10 @@ class TaglessEnvelopeFormat(
 
         //Printing meta
         if (!envelope.meta.isEmpty()) {
-            val metaBytes = metaFormat.writeBytes(envelope.meta)
-            writeProperty(META_LENGTH_PROPERTY, metaBytes.size)
+            val metaBytes = metaFormat.writePacket(envelope.meta)
+            writeProperty(META_LENGTH_PROPERTY, metaBytes.remaining)
             writeText(metaStart + "\r\n")
-            writeFully(metaBytes)
+            writePacket(metaBytes)
             writeText("\r\n")
         }
 
@@ -192,7 +192,7 @@ class TaglessEnvelopeFormat(
             return try {
                 val buffer = ByteArray(TAGLESS_ENVELOPE_HEADER.length)
                 input.readFully(buffer)
-                return if (buffer.toString() == TAGLESS_ENVELOPE_HEADER) {
+                return if (String(buffer) == TAGLESS_ENVELOPE_HEADER) {
                     TaglessEnvelopeFormat(io)
                 } else {
                     null
diff --git a/dataforge-io/src/jvmMain/kotlin/hep/dataforge/io/fileIO.kt b/dataforge-io/src/jvmMain/kotlin/hep/dataforge/io/fileIO.kt
index 14e4c077..9203d306 100644
--- a/dataforge-io/src/jvmMain/kotlin/hep/dataforge/io/fileIO.kt
+++ b/dataforge-io/src/jvmMain/kotlin/hep/dataforge/io/fileIO.kt
@@ -4,6 +4,9 @@ import hep.dataforge.descriptors.NodeDescriptor
 import hep.dataforge.meta.DFExperimental
 import hep.dataforge.meta.EmptyMeta
 import hep.dataforge.meta.Meta
+import hep.dataforge.meta.isEmpty
+import kotlinx.io.core.Output
+import kotlinx.io.core.copyTo
 import kotlinx.io.nio.asInput
 import kotlinx.io.nio.asOutput
 import java.nio.file.Files
@@ -12,10 +15,15 @@ import java.nio.file.StandardOpenOption
 import kotlin.reflect.full.isSuperclassOf
 import kotlin.streams.asSequence
 
+/**
+ * Resolve IOFormat based on type
+ */
+@DFExperimental
 inline fun <reified T : Any> IOPlugin.resolveIOFormat(): IOFormat<T>? {
     return ioFormats.values.find { it.type.isSuperclassOf(T::class) } as IOFormat<T>?
 }
 
+
 /**
  * Read file containing meta using given [formatOverride] or file extension to infer meta type.
  * If [path] is a directory search for file starting with `meta` in it
@@ -43,11 +51,12 @@ fun IOPlugin.readMetaFile(path: Path, formatOverride: MetaFormat? = null, descri
  */
 fun IOPlugin.writeMetaFile(
     path: Path,
+    meta: Meta,
     metaFormat: MetaFormatFactory = JsonMetaFormat,
     descriptor: NodeDescriptor? = null
 ) {
     val actualPath = if (Files.isDirectory(path)) {
-        path.resolve(metaFormat.name.toString())
+        path.resolve("@" + metaFormat.name.toString())
     } else {
         path
     }
@@ -58,6 +67,28 @@ fun IOPlugin.writeMetaFile(
     }
 }
 
+/**
+ * Return inferred [EnvelopeFormat] if only one format could read given file. If no format accepts file, return null. If
+ * multiple formats accepts file, throw an error.
+ */
+fun IOPlugin.peekBinaryFormat(path: Path): EnvelopeFormat? {
+    val binary = path.asBinary()
+    val formats = envelopeFormatFactories.mapNotNull { factory ->
+        binary.read {
+            factory.peekFormat(this@peekBinaryFormat, this@read)
+        }
+    }
+
+    return when (formats.size) {
+        0 -> null
+        1 -> formats.first()
+        else -> error("Envelope format binary recognition clash")
+    }
+}
+
+val IOPlugin.Companion.META_FILE_NAME: String get() = "@meta"
+val IOPlugin.Companion.DATA_FILE_NAME: String get() = "@data"
+
 /**
  * Read and envelope from file if the file exists, return null if file does not exist.
  *
@@ -72,13 +103,17 @@ fun IOPlugin.writeMetaFile(
  * Return null otherwise.
  */
 @DFExperimental
-fun IOPlugin.readEnvelopeFile(path: Path, readNonEnvelopes: Boolean = false): Envelope? {
+fun IOPlugin.readEnvelopeFile(
+    path: Path,
+    readNonEnvelopes: Boolean = false,
+    formatPeeker: IOPlugin.(Path) -> EnvelopeFormat? = IOPlugin::peekBinaryFormat
+): Envelope? {
     if (!Files.exists(path)) return null
 
     //read two-files directory
     if (Files.isDirectory(path)) {
         val metaFile = Files.list(path).asSequence()
-            .singleOrNull { it.fileName.toString().startsWith("meta") }
+            .singleOrNull { it.fileName.toString().startsWith(IOPlugin.META_FILE_NAME) }
 
         val meta = if (metaFile == null) {
             EmptyMeta
@@ -86,7 +121,7 @@ fun IOPlugin.readEnvelopeFile(path: Path, readNonEnvelopes: Boolean = false): En
             readMetaFile(metaFile)
         }
 
-        val dataFile = path.resolve("data")
+        val dataFile = path.resolve(IOPlugin.DATA_FILE_NAME)
 
         val data: Binary? = if (Files.exists(dataFile)) {
             dataFile.asBinary()
@@ -97,41 +132,76 @@ fun IOPlugin.readEnvelopeFile(path: Path, readNonEnvelopes: Boolean = false): En
         return SimpleEnvelope(meta, data)
     }
 
-    val binary = path.asBinary()
+    return formatPeeker(path)?.let { format ->
+        FileEnvelope(path, format)
+    } ?: if (readNonEnvelopes) { // if no format accepts file, read it as binary
+        SimpleEnvelope(Meta.empty, path.asBinary())
+    } else null
+}
 
-    val formats = envelopeFormatFactories.mapNotNull { factory ->
-        binary.read {
-            factory.peekFormat(this@readEnvelopeFile, this@read)
-        }
-    }
-    return when (formats.size) {
-        0 -> if (readNonEnvelopes) {
-            SimpleEnvelope(Meta.empty, binary)
-        } else {
-            null
-        }
-        1 -> formats.first().run {
-            binary.read {
-                readObject()
-            }
-        }
-        else -> error("Envelope format file recognition clash")
+private fun Path.useOutput(consumer: Output.() -> Unit) {
+    //TODO forbid rewrite?
+    Files.newByteChannel(
+        this,
+        StandardOpenOption.CREATE, StandardOpenOption.WRITE, StandardOpenOption.TRUNCATE_EXISTING
+    ).asOutput().use {
+        it.consumer()
+        it.flush()
     }
 }
 
+/**
+ * Write a binary into file. Throws an error if file already exists
+ */
+fun <T : Any> IOFormat<T>.writeToFile(path: Path, obj: T) {
+    path.useOutput {
+        writeObject(obj)
+        flush()
+    }
+}
+
+/**
+ * Write envelope file to given [path] using [envelopeFormat] and optional [metaFormat]
+ */
+@DFExperimental
 fun IOPlugin.writeEnvelopeFile(
     path: Path,
     envelope: Envelope,
-    format: EnvelopeFormat = TaggedEnvelopeFormat
+    envelopeFormat: EnvelopeFormat = TaggedEnvelopeFormat,
+    metaFormat: MetaFormatFactory? = null
 ) {
-    val output = Files.newByteChannel(
-        path,
-        StandardOpenOption.WRITE,
-        StandardOpenOption.CREATE,
-        StandardOpenOption.TRUNCATE_EXISTING
-    ).asOutput()
+    path.useOutput {
+        with(envelopeFormat) {
+            writeEnvelope(envelope, metaFormat ?: envelopeFormat.defaultMetaFormat)
+        }
+    }
+}
 
-    with(format) {
-        output.writeObject(envelope)
+/**
+ * Write separate meta and data files to given directory [path]
+ */
+@DFExperimental
+fun IOPlugin.writeEnvelopeDirectory(
+    path: Path,
+    envelope: Envelope,
+    metaFormat: MetaFormatFactory = JsonMetaFormat
+) {
+    if (!Files.exists(path)) {
+        Files.createDirectories(path)
+    }
+    if (!Files.isDirectory(path)) {
+        error("Can't write envelope directory to file")
+    }
+    if (!envelope.meta.isEmpty()) {
+        writeMetaFile(path, envelope.meta, metaFormat)
+    }
+    val dataFile = path.resolve(IOPlugin.DATA_FILE_NAME)
+    dataFile.useOutput {
+        envelope.data?.read {
+            val copied = copyTo(this@useOutput)
+            if (envelope.data?.size != ULong.MAX_VALUE && copied != envelope.data?.size?.toLong()) {
+                error("The number of copied bytes does not equal data size")
+            }
+        }
     }
 }
\ No newline at end of file
diff --git a/dataforge-io/src/jvmTest/kotlin/hep/dataforge/io/FileEnvelopeTest.kt b/dataforge-io/src/jvmTest/kotlin/hep/dataforge/io/FileEnvelopeTest.kt
index 595ca619..ccd9fb60 100644
--- a/dataforge-io/src/jvmTest/kotlin/hep/dataforge/io/FileEnvelopeTest.kt
+++ b/dataforge-io/src/jvmTest/kotlin/hep/dataforge/io/FileEnvelopeTest.kt
@@ -26,11 +26,24 @@ class FileEnvelopeTest {
 
     @Test
     fun testFileWriteRead() {
-        val tmpPath = Files.createTempFile("dataforge_test", ".df")
-        Global.io.writeEnvelopeFile(tmpPath,envelope)
-        println(tmpPath.toUri())
-        val restored: Envelope = Global.io.readEnvelopeFile(tmpPath)!!
-        assertTrue { envelope.contentEquals(restored) }
+        Global.io.run {
+            val tmpPath = Files.createTempFile("dataforge_test", ".df")
+            writeEnvelopeFile(tmpPath, envelope)
+            println(tmpPath.toUri())
+            val restored: Envelope = readEnvelopeFile(tmpPath)!!
+            assertTrue { envelope.contentEquals(restored) }
+        }
+    }
+
+    @Test
+    fun testFileWriteReadTagless() {
+        Global.io.run {
+            val tmpPath = Files.createTempFile("dataforge_test_tagless", ".df")
+            writeEnvelopeFile(tmpPath, envelope, envelopeFormat = TaglessEnvelopeFormat)
+            println(tmpPath.toUri())
+            val restored: Envelope = readEnvelopeFile(tmpPath)!!
+            assertTrue { envelope.contentEquals(restored) }
+        }
     }
 
     @Test
diff --git a/dataforge-io/src/jvmTest/kotlin/hep/dataforge/io/tcp/EnvelopeServerTest.kt b/dataforge-io/src/jvmTest/kotlin/hep/dataforge/io/tcp/EnvelopeServerTest.kt
index 37c35efc..64067dec 100644
--- a/dataforge-io/src/jvmTest/kotlin/hep/dataforge/io/tcp/EnvelopeServerTest.kt
+++ b/dataforge-io/src/jvmTest/kotlin/hep/dataforge/io/tcp/EnvelopeServerTest.kt
@@ -7,9 +7,9 @@ import hep.dataforge.io.TaggedEnvelopeFormat
 import hep.dataforge.io.writeBytes
 import kotlinx.coroutines.GlobalScope
 import kotlinx.coroutines.runBlocking
-import org.junit.AfterClass
-import org.junit.BeforeClass
-import org.junit.Test
+import org.junit.jupiter.api.AfterAll
+import org.junit.jupiter.api.BeforeAll
+import kotlin.test.Test
 import kotlin.test.assertEquals
 import kotlin.time.ExperimentalTime
 
@@ -30,13 +30,13 @@ class EnvelopeServerTest {
         @JvmStatic
         val echoEnvelopeServer = EnvelopeServer(Global, 7778, EchoResponder, GlobalScope)
 
-        @BeforeClass
+        @BeforeAll
         @JvmStatic
         fun start() {
             echoEnvelopeServer.start()
         }
 
-        @AfterClass
+        @AfterAll
         @JvmStatic
         fun close() {
             echoEnvelopeServer.stop()
diff --git a/dataforge-scripting/build.gradle.kts b/dataforge-scripting/build.gradle.kts
index 757f0c33..c848c1b1 100644
--- a/dataforge-scripting/build.gradle.kts
+++ b/dataforge-scripting/build.gradle.kts
@@ -19,8 +19,6 @@ kotlin {
         }
         val jvmTest by getting {
             dependencies {
-                implementation(kotlin("test"))
-                implementation(kotlin("test-junit"))
                 implementation("ch.qos.logback:logback-classic:1.2.3")
             }
         }
diff --git a/dataforge-scripting/src/jvmTest/kotlin/hep/dataforge/scripting/BuildersKtTest.kt b/dataforge-scripting/src/jvmTest/kotlin/hep/dataforge/scripting/BuildersKtTest.kt
index 5a9ba56d..6dd61105 100644
--- a/dataforge-scripting/src/jvmTest/kotlin/hep/dataforge/scripting/BuildersKtTest.kt
+++ b/dataforge-scripting/src/jvmTest/kotlin/hep/dataforge/scripting/BuildersKtTest.kt
@@ -6,7 +6,7 @@ import hep.dataforge.meta.int
 import hep.dataforge.workspace.SimpleWorkspaceBuilder
 import hep.dataforge.workspace.context
 import hep.dataforge.workspace.target
-import org.junit.Test
+import kotlin.test.Test
 import kotlin.test.assertEquals
 
 
diff --git a/dataforge-workspace/src/commonMain/kotlin/hep/dataforge/workspace/dataUtils.kt b/dataforge-workspace/src/commonMain/kotlin/hep/dataforge/workspace/dataUtils.kt
deleted file mode 100644
index f6d27774..00000000
--- a/dataforge-workspace/src/commonMain/kotlin/hep/dataforge/workspace/dataUtils.kt
+++ /dev/null
@@ -1,14 +0,0 @@
-package hep.dataforge.workspace
-
-import hep.dataforge.data.Data
-import hep.dataforge.io.Envelope
-import hep.dataforge.io.IOFormat
-import hep.dataforge.io.readWith
-import kotlin.reflect.KClass
-
-/**
- * Convert an [Envelope] to a data via given format. The actual parsing is done lazily.
- */
-fun <T : Any> Envelope.toData(type: KClass<out T>, format: IOFormat<T>): Data<T> = Data(type, meta) {
-    data?.readWith(format) ?: error("Can't convert envelope without data to Data")
-}
\ No newline at end of file
diff --git a/dataforge-workspace/src/commonMain/kotlin/hep/dataforge/workspace/envelopeData.kt b/dataforge-workspace/src/commonMain/kotlin/hep/dataforge/workspace/envelopeData.kt
new file mode 100644
index 00000000..111bba76
--- /dev/null
+++ b/dataforge-workspace/src/commonMain/kotlin/hep/dataforge/workspace/envelopeData.kt
@@ -0,0 +1,33 @@
+package hep.dataforge.workspace
+
+import hep.dataforge.data.Data
+import hep.dataforge.data.await
+import hep.dataforge.io.*
+import kotlinx.coroutines.coroutineScope
+import kotlinx.io.core.Input
+import kotlinx.io.core.buildPacket
+import kotlin.reflect.KClass
+
+/**
+ * Convert an [Envelope] to a data via given format. The actual parsing is done lazily.
+ */
+fun <T : Any> Envelope.toData(type: KClass<out T>, format: IOFormat<T>): Data<T> = Data(type, meta) {
+    data?.readWith(format) ?: error("Can't convert envelope without data to Data")
+}
+
+suspend fun <T : Any> Data<T>.toEnvelope(format: IOFormat<T>): Envelope {
+    val obj = coroutineScope {
+        await(this)
+    }
+    val binary = object : Binary {
+        override fun <R> read(block: Input.() -> R): R {
+            //TODO optimize away additional copy by creating inputs that reads directly from output
+            val packet = buildPacket {
+                format.run { writeObject(obj) }
+            }
+            return packet.block()
+        }
+
+    }
+    return SimpleEnvelope(meta, binary)
+}
\ No newline at end of file
diff --git a/dataforge-workspace/src/jvmMain/kotlin/hep/dataforge/workspace/fileData.kt b/dataforge-workspace/src/jvmMain/kotlin/hep/dataforge/workspace/fileData.kt
index b5ecb519..2b6d5454 100644
--- a/dataforge-workspace/src/jvmMain/kotlin/hep/dataforge/workspace/fileData.kt
+++ b/dataforge-workspace/src/jvmMain/kotlin/hep/dataforge/workspace/fileData.kt
@@ -1,17 +1,27 @@
 package hep.dataforge.workspace
 
+//import jdk.nio.zipfs.ZipFileSystemProvider
 import hep.dataforge.data.*
-import hep.dataforge.io.Envelope
-import hep.dataforge.io.IOFormat
-import hep.dataforge.io.IOPlugin
-import hep.dataforge.io.readEnvelopeFile
-import hep.dataforge.meta.Meta
-import hep.dataforge.meta.get
-import hep.dataforge.meta.string
+import hep.dataforge.io.*
+import hep.dataforge.meta.*
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
+import java.nio.file.FileSystem
 import java.nio.file.Files
 import java.nio.file.Path
+import java.nio.file.StandardCopyOption
+import java.nio.file.spi.FileSystemProvider
 import kotlin.reflect.KClass
 
+typealias FileFormatResolver<T> = (Path, Meta) -> IOFormat<T>
+
+//private val zipFSProvider = ZipFileSystemProvider()
+
+private fun newZFS(path: Path): FileSystem {
+    val fsProvider = FileSystemProvider.installedProviders().find { it.scheme == "jar" }
+        ?: error("Zip file system provider not found")
+    return fsProvider.newFileSystem(path, mapOf("create" to "true"))
+}
 
 /**
  * Read data with supported envelope format and binary format. If envelope format is null, then read binary directly from file.
@@ -22,62 +32,152 @@ import kotlin.reflect.KClass
  * @param metaFile the relative file for optional meta override
  * @param metaFileFormat the meta format for override
  */
+@DFExperimental
 fun <T : Any> IOPlugin.readDataFile(
     path: Path,
     type: KClass<out T>,
-    formatResolver: (Meta) -> IOFormat<T>
+    formatResolver: FileFormatResolver<T>
 ): Data<T> {
     val envelope = readEnvelopeFile(path, true) ?: error("Can't read data from $path")
-    val format = formatResolver(envelope.meta)
+    val format = formatResolver(path, envelope.meta)
     return envelope.toData(type, format)
 }
 
-//TODO wants multi-receiver
+@DFExperimental
+inline fun <reified T : Any> IOPlugin.readDataFile(path: Path): Data<T> =
+    readDataFile(path, T::class) { _, _ ->
+        resolveIOFormat<T>() ?: error("Can't resolve IO format for ${T::class}")
+    }
+
+/**
+ * Add file/directory-based data tree item
+ */
+@DFExperimental
 fun <T : Any> DataTreeBuilder<T>.file(
     plugin: IOPlugin,
     path: Path,
-    formatResolver: (Meta) -> IOFormat<T>
+    formatResolver: FileFormatResolver<T>
 ) {
-    plugin.run {
-        val data = readDataFile(path, type, formatResolver)
-        val name = data.meta[Envelope.ENVELOPE_NAME_KEY].string
-            ?: path.fileName.toString().replace(".df", "")
-        datum(name, data)
+    //If path is a single file or a special directory, read it as single datum
+    if (!Files.isDirectory(path) || Files.list(path).allMatch { it.fileName.toString().startsWith("@") }) {
+        plugin.run {
+            val data = readDataFile(path, type, formatResolver)
+            val name = data.meta[Envelope.ENVELOPE_NAME_KEY].string
+                ?: path.fileName.toString().replace(".df", "")
+            datum(name, data)
+        }
+    } else {
+        //otherwise, read as directory
+        plugin.run {
+            val data = readDataDirectory(path, type, formatResolver)
+            val name = data.meta[Envelope.ENVELOPE_NAME_KEY].string
+                ?: path.fileName.toString().replace(".df", "")
+            node(name, data)
+        }
     }
 }
 
 /**
- * Read the directory as a data node
+ * Read the directory as a data node. If [path] is a zip archive, read it as directory
  */
+@DFExperimental
 fun <T : Any> IOPlugin.readDataDirectory(
     path: Path,
     type: KClass<out T>,
-    formatResolver: (Meta) -> IOFormat<T>
+    formatResolver: FileFormatResolver<T>
 ): DataNode<T> {
-    if (!Files.isDirectory(path)) error("Provided path $this is not a directory")
+    //read zipped data node
+    if (path.fileName != null && path.fileName.toString().endsWith(".zip")) {
+        //Using explicit Zip file system to avoid bizarre compatibility bugs
+        val fs = newZFS(path)
+        return readDataDirectory(fs.rootDirectories.first(), type, formatResolver)
+    }
+    if (!Files.isDirectory(path)) error("Provided path $path is not a directory")
     return DataNode(type) {
         Files.list(path).forEach { path ->
-            if (!path.fileName.toString().endsWith(".meta")) {
+            val fileName = path.fileName.toString()
+            if (fileName.startsWith(IOPlugin.META_FILE_NAME)) {
+                meta(readMetaFile(path))
+            } else if (!fileName.startsWith("@")) {
                 file(this@readDataDirectory, path, formatResolver)
             }
         }
     }
 }
 
-fun <T : Any> DataTreeBuilder<T>.directory(
-    plugin: IOPlugin,
+@DFExperimental
+inline fun <reified T : Any> IOPlugin.readDataDirectory(path: Path): DataNode<T> =
+    readDataDirectory(path, T::class) { _, _ ->
+        resolveIOFormat<T>() ?: error("Can't resolve IO format for ${T::class}")
+    }
+
+/**
+ * Write data tree to existing directory or create a new one using default [java.nio.file.FileSystem] provider
+ */
+@DFExperimental
+suspend fun <T : Any> IOPlugin.writeDataDirectory(
     path: Path,
-    formatResolver: (Meta) -> IOFormat<T>
+    node: DataNode<T>,
+    format: IOFormat<T>,
+    envelopeFormat: EnvelopeFormat? = null,
+    metaFormat: MetaFormatFactory? = null
 ) {
-    plugin.run {
-        val data = readDataDirectory(path, type, formatResolver)
-        val name = data.meta[Envelope.ENVELOPE_NAME_KEY].string
-            ?: path.fileName.toString().replace(".df", "")
-        node(name, data)
+    withContext(Dispatchers.IO) {
+        if (!Files.exists(path)) {
+            Files.createDirectories(path)
+        } else if (!Files.isDirectory(path)) {
+            error("Can't write a node into file")
+        }
+        node.items.forEach { (token, item) ->
+            val childPath = path.resolve(token.toString())
+            when (item) {
+                is DataItem.Node -> {
+                    writeDataDirectory(childPath, item.node, format, envelopeFormat)
+                }
+                is DataItem.Leaf -> {
+                    val envelope = item.data.toEnvelope(format)
+                    if (envelopeFormat != null) {
+                        writeEnvelopeFile(childPath, envelope, envelopeFormat, metaFormat)
+                    } else {
+                        writeEnvelopeDirectory(childPath, envelope, metaFormat ?: JsonMetaFormat)
+                    }
+                }
+            }
+        }
+        if (!node.meta.isEmpty()) {
+            writeMetaFile(path, node.meta, metaFormat ?: JsonMetaFormat)
+        }
     }
 }
 
-
-
-
+suspend fun <T : Any> IOPlugin.writeZip(
+    path: Path,
+    node: DataNode<T>,
+    format: IOFormat<T>,
+    envelopeFormat: EnvelopeFormat? = null,
+    metaFormat: MetaFormatFactory? = null
+) {
+    withContext(Dispatchers.IO) {
+        val actualFile = if (path.toString().endsWith(".zip")) {
+            path
+        } else {
+            path.resolveSibling(path.fileName.toString() + ".zip")
+        }
+        if (Files.exists(actualFile) && Files.size(path) == 0.toLong()) {
+            Files.delete(path)
+        }
+        //Files.createFile(actualFile)
+        newZFS(actualFile).use { zipfs ->
+            val internalTargetPath = zipfs.getPath("/")
+            Files.createDirectories(internalTargetPath)
+            val tmp = Files.createTempDirectory("df_zip")
+            writeDataDirectory(tmp, node, format, envelopeFormat, metaFormat)
+            Files.list(tmp).forEach { sourcePath ->
+                val targetPath = sourcePath.fileName.toString()
+                val internalTargetPath = internalTargetPath.resolve(targetPath)
+                Files.copy(sourcePath, internalTargetPath, StandardCopyOption.REPLACE_EXISTING)
+            }
+        }
+    }
+}
 
diff --git a/dataforge-workspace/src/jvmTest/kotlin/hep/dataforge/workspace/DataPropagationTest.kt b/dataforge-workspace/src/jvmTest/kotlin/hep/dataforge/workspace/DataPropagationTest.kt
index c449ffc3..083d3f57 100644
--- a/dataforge-workspace/src/jvmTest/kotlin/hep/dataforge/workspace/DataPropagationTest.kt
+++ b/dataforge-workspace/src/jvmTest/kotlin/hep/dataforge/workspace/DataPropagationTest.kt
@@ -6,8 +6,8 @@ import hep.dataforge.context.PluginTag
 import hep.dataforge.data.*
 import hep.dataforge.meta.Meta
 import hep.dataforge.names.asName
-import org.junit.Test
 import kotlin.reflect.KClass
+import kotlin.test.Test
 import kotlin.test.assertEquals
 
 
diff --git a/dataforge-workspace/src/jvmTest/kotlin/hep/dataforge/workspace/FileDataTest.kt b/dataforge-workspace/src/jvmTest/kotlin/hep/dataforge/workspace/FileDataTest.kt
new file mode 100644
index 00000000..b73a4d59
--- /dev/null
+++ b/dataforge-workspace/src/jvmTest/kotlin/hep/dataforge/workspace/FileDataTest.kt
@@ -0,0 +1,72 @@
+package hep.dataforge.workspace
+
+import hep.dataforge.context.Global
+import hep.dataforge.data.*
+import hep.dataforge.io.IOFormat
+import hep.dataforge.io.io
+import hep.dataforge.meta.DFExperimental
+import kotlinx.coroutines.runBlocking
+import kotlinx.io.core.Input
+import kotlinx.io.core.Output
+import kotlinx.io.core.readText
+import kotlinx.io.core.writeText
+import java.nio.file.Files
+import kotlin.test.Ignore
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class FileDataTest {
+    val dataNode = DataNode<String> {
+        node("dir") {
+            static("a", "Some string") {
+                "content" put "Some string"
+            }
+        }
+        static("b", "root data")
+        meta {
+            "content" put "This is root meta node"
+        }
+    }
+
+    object StringIOFormat : IOFormat<String> {
+        override fun Output.writeObject(obj: String) {
+            writeText(obj)
+        }
+
+        override fun Input.readObject(): String {
+            return readText()
+        }
+
+    }
+
+    @Test
+    @DFExperimental
+    fun testDataWriteRead() {
+        Global.io.run {
+            val dir = Files.createTempDirectory("df_data_node")
+            runBlocking {
+                writeDataDirectory(dir, dataNode, StringIOFormat)
+            }
+            println(dir.toUri().toString())
+            val reconstructed = readDataDirectory(dir, String::class) { _, _ -> StringIOFormat }
+            assertEquals(dataNode["dir.a"]?.meta, reconstructed["dir.a"]?.meta)
+            assertEquals(dataNode["b"]?.data?.get(), reconstructed["b"]?.data?.get())
+        }
+    }
+
+
+    @Test
+    @Ignore
+    fun testZipWriteRead() {
+        Global.io.run {
+            val zip = Files.createTempFile("df_data_node", ".zip")
+            runBlocking {
+                writeZip(zip, dataNode, StringIOFormat)
+            }
+            println(zip.toUri().toString())
+            val reconstructed = readDataDirectory(zip, String::class) { _, _ -> StringIOFormat }
+            assertEquals(dataNode["dir.a"]?.meta, reconstructed["dir.a"]?.meta)
+            assertEquals(dataNode["b"]?.data?.get(), reconstructed["b"]?.data?.get())
+        }
+    }
+}
\ No newline at end of file
diff --git a/dataforge-workspace/src/jvmTest/kotlin/hep/dataforge/workspace/SimpleWorkspaceTest.kt b/dataforge-workspace/src/jvmTest/kotlin/hep/dataforge/workspace/SimpleWorkspaceTest.kt
index 3a40e783..a4df6a4b 100644
--- a/dataforge-workspace/src/jvmTest/kotlin/hep/dataforge/workspace/SimpleWorkspaceTest.kt
+++ b/dataforge-workspace/src/jvmTest/kotlin/hep/dataforge/workspace/SimpleWorkspaceTest.kt
@@ -7,7 +7,7 @@ import hep.dataforge.meta.builder
 import hep.dataforge.meta.get
 import hep.dataforge.meta.int
 import hep.dataforge.names.plus
-import org.junit.Test
+import kotlin.test.Test
 import kotlin.test.assertEquals
 import kotlin.test.assertTrue
 
diff --git a/gradle/wrapper/gradle-wrapper.jar b/gradle/wrapper/gradle-wrapper.jar
index 5c2d1cf0..cc4fdc29 100644
Binary files a/gradle/wrapper/gradle-wrapper.jar and b/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index 7c4388a9..6ce793f2 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-5.6.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.0-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/gradlew b/gradlew
old mode 100644
new mode 100755
index 83f2acfd..2fe81a7d
--- a/gradlew
+++ b/gradlew
@@ -154,19 +154,19 @@ if [ "$cygwin" = "true" -o "$msys" = "true" ] ; then
         else
             eval `echo args$i`="\"$arg\""
         fi
-        i=$((i+1))
+        i=`expr $i + 1`
     done
     case $i in
-        (0) set -- ;;
-        (1) set -- "$args0" ;;
-        (2) set -- "$args0" "$args1" ;;
-        (3) set -- "$args0" "$args1" "$args2" ;;
-        (4) set -- "$args0" "$args1" "$args2" "$args3" ;;
-        (5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
-        (6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
-        (7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
-        (8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
-        (9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+        0) set -- ;;
+        1) set -- "$args0" ;;
+        2) set -- "$args0" "$args1" ;;
+        3) set -- "$args0" "$args1" "$args2" ;;
+        4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
     esac
 fi
 
@@ -175,14 +175,9 @@ save () {
     for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
     echo " "
 }
-APP_ARGS=$(save "$@")
+APP_ARGS=`save "$@"`
 
 # Collect all arguments for the java command, following the shell quoting and substitution rules
 eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
 
-# by default we should be in the correct project dir, but when run from Finder on Mac, the cwd is wrong
-if [ "$(uname)" = "Darwin" ] && [ "$HOME" = "$PWD" ]; then
-  cd "$(dirname "$0")"
-fi
-
 exec "$JAVACMD" "$@"