diff --git a/build.gradle.kts b/build.gradle.kts
index cd3e5d61..7f190853 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -6,7 +6,7 @@ plugins {
     id("scientifik.publish") version "0.2.2" apply false
 }
 
-val dataforgeVersion by extra("0.1.5-dev-1")
+val dataforgeVersion by extra("0.1.5-dev-2")
 
 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 12bb06ab..65c07676 100644
--- a/dataforge-data/src/commonMain/kotlin/hep/dataforge/data/DataNode.kt
+++ b/dataforge-data/src/commonMain/kotlin/hep/dataforge/data/DataNode.kt
@@ -13,16 +13,22 @@ import kotlin.reflect.KClass
 sealed class DataItem<out T : Any> : MetaRepr {
     abstract val type: KClass<out T>
 
+    abstract val meta: Meta
+
     class Node<out T : Any>(val value: DataNode<T>) : DataItem<T>() {
         override val type: KClass<out T> get() = value.type
 
         override fun toMeta(): Meta = value.toMeta()
+
+        override val meta: Meta get() = value.meta
     }
 
     class Leaf<out T : Any>(val value: Data<T>) : DataItem<T>() {
         override val type: KClass<out T> get() = value.type
 
         override fun toMeta(): Meta = value.toMeta()
+
+        override val meta: Meta get() = value.meta
     }
 }
 
@@ -38,6 +44,8 @@ interface DataNode<out T : Any> : MetaRepr {
 
     val items: Map<NameToken, DataItem<T>>
 
+    val meta: Meta
+
     override fun toMeta(): Meta = buildMeta {
         "type" put (type.simpleName ?: "undefined")
         "items" put {
@@ -64,21 +72,13 @@ val <T : Any> DataItem<T>?.node: DataNode<T>? get() = (this as? DataItem.Node<T>
 val <T : Any> DataItem<T>?.data: Data<T>? get() = (this as? DataItem.Leaf<T>)?.value
 
 /**
- * Start computation for all goals in data node
+ * Start computation for all goals in data node and return a job for the whole node
  */
-fun DataNode<*>.startAll(scope: CoroutineScope): Unit = items.values.forEach {
-    when (it) {
-        is DataItem.Node<*> -> it.value.startAll(scope)
-        is DataItem.Leaf<*> -> it.value.start(scope)
-    }
-}
-
-fun DataNode<*>.joinAll(scope: CoroutineScope): Job = scope.launch {
-    startAll(scope)
-    items.forEach {
-        when (val value = it.value) {
-            is DataItem.Node -> value.value.joinAll(this).join()
-            is DataItem.Leaf -> value.value.await(scope)
+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)
         }
     }
 }
@@ -125,12 +125,9 @@ operator fun <T : Any> DataNode<T>.iterator(): Iterator<Pair<Name, DataItem<T>>>
 
 class DataTree<out T : Any> internal constructor(
     override val type: KClass<out T>,
-    override val items: Map<NameToken, DataItem<T>>
-) : DataNode<T> {
-    override fun toString(): String {
-        return super.toString()
-    }
-}
+    override val items: Map<NameToken, DataItem<T>>,
+    override val meta: Meta
+) : DataNode<T>
 
 private sealed class DataTreeBuilderItem<out T : Any> {
     class Node<T : Any>(val tree: DataTreeBuilder<T>) : DataTreeBuilderItem<T>()
@@ -144,6 +141,8 @@ private sealed class DataTreeBuilderItem<out T : Any> {
 class DataTreeBuilder<T : Any>(val type: KClass<out T>) {
     private val map = HashMap<NameToken, DataTreeBuilderItem<T>>()
 
+    private var meta = MetaBuilder()
+
     operator fun set(token: NameToken, node: DataTreeBuilder<out T>) {
         if (map.containsKey(token)) error("Tree entry with name $token is not empty")
         map[token] = DataTreeBuilderItem.Node(node)
@@ -211,13 +210,19 @@ class DataTreeBuilder<T : Any>(val type: KClass<out T>) {
     infix fun String.put(block: DataTreeBuilder<T>.() -> Unit) = set(toName(), DataTreeBuilder(type).apply(block))
 
 
+    /**
+     * Update data with given node data and meta with node meta.
+     */
     fun update(node: DataNode<T>) {
         node.dataSequence().forEach {
             //TODO check if the place is occupied
             this[it.first] = it.second
         }
+        meta.update(node.meta)
     }
 
+    fun meta(block: MetaBuilder.() -> Unit) = meta.apply(block)
+
     fun build(): DataTree<T> {
         val resMap = map.mapValues { (_, value) ->
             when (value) {
@@ -225,7 +230,7 @@ class DataTreeBuilder<T : Any>(val type: KClass<out T>) {
                 is DataTreeBuilderItem.Node -> DataItem.Node(value.tree.build())
             }
         }
-        return DataTree(type, resMap)
+        return DataTree(type, resMap, meta.seal())
     }
 }
 
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 556b77fc..0b9a4910 100644
--- a/dataforge-data/src/commonMain/kotlin/hep/dataforge/data/dataCast.kt
+++ b/dataforge-data/src/commonMain/kotlin/hep/dataforge/data/dataCast.kt
@@ -52,6 +52,7 @@ inline fun <reified R : Any> Data<*>.cast(): Data<R> = cast(R::class)
 @Suppress("UNCHECKED_CAST")
 fun <R : Any> DataNode<*>.cast(type: KClass<out R>): DataNode<R> {
     return object : DataNode<R> {
+        override val meta: Meta get() = this@cast.meta
         override val type: KClass<out R> = type
         override val items: Map<NameToken, DataItem<R>> get() = this@cast.items as Map<NameToken, DataItem<R>>
     }
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 d24de964..331f3b0e 100644
--- a/dataforge-data/src/jvmMain/kotlin/hep/dataforge/data/TypeFilteredDataNode.kt
+++ b/dataforge-data/src/jvmMain/kotlin/hep/dataforge/data/TypeFilteredDataNode.kt
@@ -1,5 +1,6 @@
 package hep.dataforge.data
 
+import hep.dataforge.meta.Meta
 import hep.dataforge.names.NameToken
 import kotlin.reflect.KClass
 
@@ -8,6 +9,7 @@ import kotlin.reflect.KClass
  * A zero-copy data node wrapper that returns only children with appropriate type.
  */
 class TypeFilteredDataNode<out T : Any>(val origin: DataNode<*>, override val type: KClass<out T>) : DataNode<T> {
+    override val meta: Meta get() = origin.meta
     override val items: Map<NameToken, DataItem<T>> by lazy {
         origin.items.mapNotNull { (key, item) ->
             when (item) {
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 5b5507b2..29d048ed 100644
--- a/dataforge-data/src/jvmMain/kotlin/hep/dataforge/data/dataJVM.kt
+++ b/dataforge-data/src/jvmMain/kotlin/hep/dataforge/data/dataJVM.kt
@@ -30,12 +30,10 @@ fun <R : Any> Data<*>.filterIsInstance(type: KClass<out R>): Data<R>? =
  * but could contain empty nodes
  */
 fun <R : Any> DataNode<*>.filterIsInstance(type: KClass<out R>): DataNode<R> {
-    return if (canCast(type)) {
-        cast(type)
-    } else if (this is TypeFilteredDataNode) {
-        origin.filterIsInstance(type)
-    } else {
-        TypeFilteredDataNode(this, type)
+    return when {
+        canCast(type) -> cast(type)
+        this is TypeFilteredDataNode -> origin.filterIsInstance(type)
+        else -> TypeFilteredDataNode(this, type)
     }
 }
 
diff --git a/dataforge-io/dataforge-io-yaml/src/main/kotlin/hep/dataforge/io/yaml/FrontMatterEnvelopeFormat.kt b/dataforge-io/dataforge-io-yaml/src/main/kotlin/hep/dataforge/io/yaml/FrontMatterEnvelopeFormat.kt
index db701625..023635e2 100644
--- a/dataforge-io/dataforge-io-yaml/src/main/kotlin/hep/dataforge/io/yaml/FrontMatterEnvelopeFormat.kt
+++ b/dataforge-io/dataforge-io-yaml/src/main/kotlin/hep/dataforge/io/yaml/FrontMatterEnvelopeFormat.kt
@@ -24,7 +24,7 @@ class FrontMatterEnvelopeFormat(
 
         val readMetaFormat =
             metaTypeRegex.matchEntire(line)?.groupValues?.first()
-                ?.let { io.metaFormat(it) } ?: YamlMetaFormat.default
+                ?.let { io.metaFormat(it) } ?: YamlMetaFormat
 
         val metaBlock = buildPacket {
             do {
@@ -45,7 +45,7 @@ class FrontMatterEnvelopeFormat(
 
         val readMetaFormat =
             metaTypeRegex.matchEntire(line)?.groupValues?.first()
-                ?.let { io.metaFormat(it) } ?: YamlMetaFormat.default
+                ?.let { io.metaFormat(it) } ?: YamlMetaFormat
 
         val metaBlock = buildPacket {
             do {
@@ -72,7 +72,7 @@ class FrontMatterEnvelopeFormat(
         private val metaTypeRegex = "---(\\w*)\\s*".toRegex()
 
         override fun invoke(meta: Meta, context: Context): EnvelopeFormat {
-            return FrontMatterEnvelopeFormat(context.io,  meta)
+            return FrontMatterEnvelopeFormat(context.io, meta)
         }
 
         override fun peekFormat(io: IOPlugin, input: Input): EnvelopeFormat? {
@@ -84,5 +84,16 @@ class FrontMatterEnvelopeFormat(
             }
         }
 
+        private val default by lazy { invoke() }
+
+        override fun Input.readPartial(): PartialEnvelope =
+            default.run { readPartial() }
+
+        override fun Output.writeEnvelope(envelope: Envelope, metaFormatFactory: MetaFormatFactory, formatMeta: Meta) =
+            default.run { writeEnvelope(envelope, metaFormatFactory, formatMeta) }
+
+        override fun Input.readObject(): Envelope =
+            default.run { readObject() }
+
     }
 }
\ No newline at end of file
diff --git a/dataforge-io/dataforge-io-yaml/src/main/kotlin/hep/dataforge/io/yaml/YamlMetaFormat.kt b/dataforge-io/dataforge-io-yaml/src/main/kotlin/hep/dataforge/io/yaml/YamlMetaFormat.kt
index 24ea44ec..7130518d 100644
--- a/dataforge-io/dataforge-io-yaml/src/main/kotlin/hep/dataforge/io/yaml/YamlMetaFormat.kt
+++ b/dataforge-io/dataforge-io-yaml/src/main/kotlin/hep/dataforge/io/yaml/YamlMetaFormat.kt
@@ -45,12 +45,18 @@ class YamlMetaFormat(val meta: Meta) : MetaFormat {
     }
 
     companion object : MetaFormatFactory {
-        val default = YamlMetaFormat()
-
         override fun invoke(meta: Meta, context: Context): MetaFormat = YamlMetaFormat(meta)
 
         override val name: Name = super.name + "yaml"
 
         override val key: Short = 0x594d //YM
+
+        private val default = YamlMetaFormat()
+
+        override fun Output.writeMeta(meta: Meta, descriptor: NodeDescriptor?) =
+            default.run { writeMeta(meta, descriptor) }
+
+        override fun Input.readMeta(descriptor: NodeDescriptor?): Meta =
+            default.run { readMeta(descriptor) }
     }
 }
\ No newline at end of file
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 ca05de4d..bd1f2249 100644
--- a/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/Binary.kt
+++ b/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/Binary.kt
@@ -8,7 +8,7 @@ import kotlin.math.min
  */
 interface Binary {
     /**
-     * The size of binary in bytes
+     * 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
 
@@ -18,6 +18,10 @@ interface Binary {
      * Some implementation may forbid this to be called twice. In this case second call will throw an exception.
      */
     fun <R> read(block: Input.() -> R): R
+
+    companion object {
+        val EMPTY = EmptyBinary
+    }
 }
 
 /**
@@ -48,12 +52,11 @@ fun RandomAccessBinary.readPacket(from: UInt, size: UInt): ByteReadPacket = read
 @ExperimentalUnsignedTypes
 object EmptyBinary : RandomAccessBinary {
 
-    override val size: ULong = 0.toULong()
+    override val size: ULong = 0u
 
     override fun <R> read(from: UInt, size: UInt, block: Input.() -> R): R {
         error("The binary is empty")
     }
-
 }
 
 @ExperimentalUnsignedTypes
@@ -79,9 +82,9 @@ fun <T : Any> Binary.readWith(format: IOFormat<T>): T = format.run {
     }
 }
 
-fun <T : Any> IOFormat<T>.writeBinary(obj: T): Binary {
-    val packet = buildPacket {
-        writeObject(obj)
-    }
-    return ArrayBinary(packet.readBytes())
-}
\ No newline at end of file
+//fun <T : Any> IOFormat<T>.writeBinary(obj: T): Binary {
+//    val packet = buildPacket {
+//        writeObject(obj)
+//    }
+//    return ArrayBinary(packet.readBytes())
+//}
\ No newline at end of file
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 61aeb4d2..7cb918df 100644
--- a/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/Envelope.kt
+++ b/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/Envelope.kt
@@ -21,6 +21,7 @@ interface Envelope {
         val ENVELOPE_DATA_TYPE_KEY = ENVELOPE_NODE_KEY + "dataType"
         val ENVELOPE_DATA_ID_KEY = ENVELOPE_NODE_KEY + "dataID"
         val ENVELOPE_DESCRIPTION_KEY = ENVELOPE_NODE_KEY + "description"
+        val ENVELOPE_NAME_KEY = ENVELOPE_NODE_KEY + "name"
         //const val ENVELOPE_TIME_KEY = "@envelope.time"
 
         /**
diff --git a/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/EnvelopeBuilder.kt b/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/EnvelopeBuilder.kt
index b8d0b660..354b4586 100644
--- a/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/EnvelopeBuilder.kt
+++ b/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/EnvelopeBuilder.kt
@@ -21,6 +21,7 @@ class EnvelopeBuilder {
     var dataType by metaBuilder.string(key = Envelope.ENVELOPE_DATA_TYPE_KEY)
     var dataID by metaBuilder.string(key = Envelope.ENVELOPE_DATA_ID_KEY)
     var description by metaBuilder.string(key = Envelope.ENVELOPE_DESCRIPTION_KEY)
+    var name by metaBuilder.string(key = Envelope.ENVELOPE_NAME_KEY)
 
     /**
      * Construct a binary and transform it into byte-array based buffer
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 c52b9e1d..4f747ea2 100644
--- a/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/EnvelopeFormat.kt
+++ b/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/EnvelopeFormat.kt
@@ -31,7 +31,7 @@ interface EnvelopeFormat : IOFormat<Envelope> {
 }
 
 @Type(ENVELOPE_FORMAT_TYPE)
-interface EnvelopeFormatFactory : IOFormatFactory<Envelope> {
+interface EnvelopeFormatFactory : IOFormatFactory<Envelope>, EnvelopeFormat {
     override val name: Name get() = "envelope".asName()
     override val type: KClass<out Envelope> get() = Envelope::class
 
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 ca4efea4..eb1dd696 100644
--- a/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/EnvelopeParts.kt
+++ b/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/EnvelopeParts.kt
@@ -3,27 +3,31 @@ 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.PARTS_DATA_TYPE
+import hep.dataforge.io.EnvelopeParts.MULTIPART_DATA_TYPE
 import hep.dataforge.io.EnvelopeParts.SIZE_KEY
 import hep.dataforge.meta.*
+import hep.dataforge.names.asName
 import hep.dataforge.names.plus
 import hep.dataforge.names.toName
 
 object EnvelopeParts {
-    val SIZE_KEY = Envelope.ENVELOPE_NODE_KEY + "parts" + "size"
-    val FORMAT_NAME_KEY = Envelope.ENVELOPE_NODE_KEY + "parts" + "format"
-    val FORMAT_META_KEY = Envelope.ENVELOPE_NODE_KEY + "parts" + "meta"
+    val MULTIPART_KEY = "multipart".asName()
+    val SIZE_KEY = Envelope.ENVELOPE_NODE_KEY + MULTIPART_KEY + "size"
+    val FORMAT_NAME_KEY = Envelope.ENVELOPE_NODE_KEY + MULTIPART_KEY + "format"
+    val FORMAT_META_KEY = Envelope.ENVELOPE_NODE_KEY + MULTIPART_KEY + "meta"
 
-    const val PARTS_DATA_TYPE = "envelope.parts"
+    const val MULTIPART_DATA_TYPE = "envelope.multipart"
 }
 
-fun EnvelopeBuilder.parts(formatFactory: EnvelopeFormatFactory, envelopes: Collection<Envelope>) {
-    dataType = PARTS_DATA_TYPE
+/**
+ * Append multiple serialized envelopes to the data block. Previous data is erased if it was present
+ */
+fun EnvelopeBuilder.multipart(format: EnvelopeFormatFactory, envelopes: Collection<Envelope>) {
+    dataType = MULTIPART_DATA_TYPE
     meta {
         SIZE_KEY put envelopes.size
-        FORMAT_NAME_KEY put formatFactory.name.toString()
+        FORMAT_NAME_KEY put format.name.toString()
     }
-    val format = formatFactory()
     data {
         format.run {
             envelopes.forEach {
@@ -33,12 +37,15 @@ fun EnvelopeBuilder.parts(formatFactory: EnvelopeFormatFactory, envelopes: Colle
     }
 }
 
-fun EnvelopeBuilder.parts(formatFactory: EnvelopeFormatFactory, builder: suspend SequenceScope<Envelope>.() -> Unit) =
-    parts(formatFactory, sequence(builder).toList())
+fun EnvelopeBuilder.multipart(formatFactory: EnvelopeFormatFactory, builder: suspend SequenceScope<Envelope>.() -> Unit) =
+    multipart(formatFactory, sequence(builder).toList())
 
-fun Envelope.parts(io: IOPlugin = Global.plugins.fetch(IOPlugin)): Sequence<Envelope> {
+/**
+ * If given envelope supports multipart data, return a sequence of those parts (could be empty). Otherwise return null.
+ */
+fun Envelope.parts(io: IOPlugin = Global.plugins.fetch(IOPlugin)): Sequence<Envelope>? {
     return when (dataType) {
-        PARTS_DATA_TYPE -> {
+        MULTIPART_DATA_TYPE -> {
             val size = meta[SIZE_KEY].int ?: error("Unsized parts not supported yet")
             val formatName = meta[FORMAT_NAME_KEY].string?.toName()
                 ?: error("Inferring parts format is not supported at the moment")
@@ -55,6 +62,6 @@ fun Envelope.parts(io: IOPlugin = Global.plugins.fetch(IOPlugin)): Sequence<Enve
                 } ?: emptySequence()
             }
         }
-        else -> emptySequence()
+        else -> 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 093ffbc8..bd1e54f4 100644
--- a/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/IOFormat.kt
+++ b/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/IOFormat.kt
@@ -16,7 +16,6 @@ import kotlinx.serialization.ImplicitReflectionSerializer
 import kotlinx.serialization.KSerializer
 import kotlinx.serialization.cbor.Cbor
 import kotlinx.serialization.serializer
-import kotlin.math.min
 import kotlin.reflect.KClass
 
 /**
@@ -80,33 +79,9 @@ 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
 fun <T : Any> IOFormat<T>.writeBytes(obj: T): ByteArray = buildPacket { writeObject(obj) }.readBytes()
-fun <T : Any> IOFormat<T>.readBytes(array: ByteArray): T {
-    //= ByteReadPacket(array).readThis()
-    val byteArrayInput: Input = object : AbstractInput(
-        IoBuffer.Pool.borrow(),
-        remaining = array.size.toLong(),
-        pool = IoBuffer.Pool
-    ) {
-        var written = 0
-        override fun closeSource() {
-            // do nothing
-        }
-
-        override fun fill(): IoBuffer? {
-            if (array.size - written <= 0) return null
-
-            return IoBuffer.Pool.fill {
-                reserveEndGap(IoBuffer.ReservedSize)
-                val toWrite = min(capacity, array.size - written)
-                writeFully(array, written, toWrite)
-                written += toWrite
-            }
-        }
-
-    }
-    return byteArrayInput.readObject()
-}
+fun <T : Any> IOFormat<T>.readBytes(array: ByteArray): T = buildPacket { writeFully(array) }.readObject()
 
 object DoubleIOFormat : IOFormat<Double>, IOFormatFactory<Double> {
     override fun invoke(meta: Meta, context: Context): IOFormat<Double> = this
diff --git a/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/JsonMetaFormat.kt b/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/JsonMetaFormat.kt
index a95cdec4..5c10505d 100644
--- a/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/JsonMetaFormat.kt
+++ b/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/JsonMetaFormat.kt
@@ -38,12 +38,18 @@ class JsonMetaFormat(private val json: Json = Json.indented) : MetaFormat {
     }
 
     companion object : MetaFormatFactory {
-        val default = JsonMetaFormat()
-
         override fun invoke(meta: Meta, context: Context): MetaFormat = default
 
         override val name: Name = super.name + "json"
         override val key: Short = 0x4a53//"JS"
+
+        private val default = JsonMetaFormat()
+
+        override fun Output.writeMeta(meta: Meta, descriptor: NodeDescriptor?) =
+            default.run { writeMeta(meta,descriptor) }
+
+        override fun Input.readMeta(descriptor: NodeDescriptor?): Meta =
+            default.run { readMeta(descriptor) }
     }
 }
 
@@ -90,7 +96,7 @@ fun Meta.toJson(descriptor: NodeDescriptor? = null): JsonObject {
 fun JsonElement.toMeta(descriptor: NodeDescriptor? = null): Meta {
     return when (val item = toMetaItem(descriptor)) {
         is MetaItem.NodeItem<*> -> item.node
-        is MetaItem.ValueItem ->item.value.toMeta()
+        is MetaItem.ValueItem -> item.value.toMeta()
     }
 }
 
diff --git a/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/MetaFormat.kt b/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/MetaFormat.kt
index ca9a53a2..9d1af81a 100644
--- a/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/MetaFormat.kt
+++ b/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/MetaFormat.kt
@@ -27,7 +27,7 @@ interface MetaFormat : IOFormat<Meta> {
 }
 
 @Type(META_FORMAT_TYPE)
-interface MetaFormatFactory : IOFormatFactory<Meta> {
+interface MetaFormatFactory : IOFormatFactory<Meta>, MetaFormat {
     override val name: Name get() = "meta".asName()
 
     override val type: KClass<out Meta> get() = Meta::class
@@ -47,7 +47,7 @@ fun Meta.toString(format: MetaFormat): String = buildPacket {
 
 fun Meta.toString(formatFactory: MetaFormatFactory): String = toString(formatFactory())
 
-fun Meta.toBytes(format: MetaFormat = JsonMetaFormat.default): ByteReadPacket = buildPacket {
+fun Meta.toBytes(format: MetaFormat = JsonMetaFormat): ByteReadPacket = buildPacket {
     format.run { writeObject(this@toBytes) }
 }
 
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 cce3eade..a95b7bfb 100644
--- a/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/TaggedEnvelopeFormat.kt
+++ b/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/TaggedEnvelopeFormat.kt
@@ -39,7 +39,12 @@ 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 tag = Tag(metaFormatFactory.key, metaBytes.size.toUInt() + 2u, envelope.data?.size ?: 0.toULong())
+        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)
         writePacket(tag.toBytes())
         writeFully(metaBytes)
         writeText("\r\n")
@@ -59,7 +64,10 @@ class TaggedEnvelopeFormat(
         val metaFormat = io.metaFormat(tag.metaFormatKey)
             ?: error("Meta format with key ${tag.metaFormatKey} not found")
 
-        val metaPacket = ByteReadPacket(readBytes(tag.metaSize.toInt()))
+        val metaBytes = readBytes(tag.metaSize.toInt())
+        val metaPacket = buildPacket {
+            writeFully(metaBytes)
+        }
         val dataBytes = readBytes(tag.dataSize.toInt())
 
         val meta = metaFormat.run { metaPacket.readObject() }
@@ -134,7 +142,16 @@ class TaggedEnvelopeFormat(
             }
         }
 
-        val default by lazy { invoke() }
+        private val default by lazy { invoke() }
+
+        override fun Input.readPartial(): PartialEnvelope =
+            default.run { readPartial() }
+
+        override fun Output.writeEnvelope(envelope: Envelope, metaFormatFactory: MetaFormatFactory, formatMeta: Meta) =
+            default.run { writeEnvelope(envelope, metaFormatFactory, formatMeta) }
+
+        override fun Input.readObject(): Envelope =
+            default.run { readObject() }
     }
 
 }
\ No newline at end of file
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 c9d32c9f..a8f84be0 100644
--- a/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/TaglessEnvelopeFormat.kt
+++ b/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/TaglessEnvelopeFormat.kt
@@ -27,7 +27,13 @@ class TaglessEnvelopeFormat(
         //printing all properties
         writeProperty(META_TYPE_PROPERTY, metaFormatFactory.type)
         //TODO add optional metaFormat properties
-        writeProperty(DATA_LENGTH_PROPERTY, envelope.data?.size ?: 0)
+        val actualSize: ULong = if (envelope.data == null) {
+            0u
+        } else {
+            envelope.data?.size ?: ULong.MAX_VALUE
+        }
+
+        writeProperty(DATA_LENGTH_PROPERTY, actualSize)
 
         //Printing meta
         if (!envelope.meta.isEmpty()) {
@@ -67,7 +73,7 @@ class TaglessEnvelopeFormat(
         var meta: Meta = EmptyMeta
 
         if (line.startsWith(metaStart)) {
-            val metaFormat = properties[META_TYPE_PROPERTY]?.let { io.metaFormat(it) } ?: JsonMetaFormat.default
+            val metaFormat = properties[META_TYPE_PROPERTY]?.let { io.metaFormat(it) } ?: JsonMetaFormat
             val metaSize = properties.get(META_LENGTH_PROPERTY)?.toInt()
             meta = if (metaSize != null) {
                 val metaPacket = buildPacket {
@@ -122,7 +128,7 @@ class TaglessEnvelopeFormat(
         var meta: Meta = EmptyMeta
 
         if (line.startsWith(metaStart)) {
-            val metaFormat = properties[META_TYPE_PROPERTY]?.let { io.metaFormat(it) } ?: JsonMetaFormat.default
+            val metaFormat = properties[META_TYPE_PROPERTY]?.let { io.metaFormat(it) } ?: JsonMetaFormat
 
             val metaSize = properties.get(META_LENGTH_PROPERTY)?.toInt()
             meta = if (metaSize != null) {
@@ -171,7 +177,16 @@ class TaglessEnvelopeFormat(
             return TaglessEnvelopeFormat(context.io, meta)
         }
 
-        val default by lazy { invoke() }
+        private val default by lazy { invoke() }
+
+        override fun Input.readPartial(): PartialEnvelope =
+            default.run { readPartial() }
+
+        override fun Output.writeEnvelope(envelope: Envelope, metaFormatFactory: MetaFormatFactory, formatMeta: Meta) =
+            default.run { writeEnvelope(envelope, metaFormatFactory, formatMeta) }
+
+        override fun Input.readObject(): Envelope =
+            default.run { readObject() }
 
         override fun peekFormat(io: IOPlugin, input: Input): EnvelopeFormat? {
             return try {
diff --git a/dataforge-io/src/commonTest/kotlin/hep/dataforge/io/EnvelopeFormatTest.kt b/dataforge-io/src/commonTest/kotlin/hep/dataforge/io/EnvelopeFormatTest.kt
index 29e60f2f..37ee827d 100644
--- a/dataforge-io/src/commonTest/kotlin/hep/dataforge/io/EnvelopeFormatTest.kt
+++ b/dataforge-io/src/commonTest/kotlin/hep/dataforge/io/EnvelopeFormatTest.kt
@@ -18,7 +18,7 @@ class EnvelopeFormatTest {
     @ExperimentalStdlibApi
     @Test
     fun testTaggedFormat(){
-        TaggedEnvelopeFormat.default.run {
+        TaggedEnvelopeFormat.run {
             val bytes = writeBytes(envelope)
             println(bytes.decodeToString())
             val res = readBytes(bytes)
@@ -32,7 +32,7 @@ class EnvelopeFormatTest {
 
     @Test
     fun testTaglessFormat(){
-        TaglessEnvelopeFormat.default.run {
+        TaglessEnvelopeFormat.run {
             val bytes = writeBytes(envelope)
             println(bytes.decodeToString())
             val res = readBytes(bytes)
diff --git a/dataforge-io/src/commonTest/kotlin/hep/dataforge/io/EnvelopePartsTest.kt b/dataforge-io/src/commonTest/kotlin/hep/dataforge/io/EnvelopePartsTest.kt
index 5122680a..d123d632 100644
--- a/dataforge-io/src/commonTest/kotlin/hep/dataforge/io/EnvelopePartsTest.kt
+++ b/dataforge-io/src/commonTest/kotlin/hep/dataforge/io/EnvelopePartsTest.kt
@@ -14,19 +14,23 @@ class EnvelopePartsTest {
             }
             data {
                 writeText("Hello World $it")
+                repeat(200){
+                    writeInt(it)
+                }
             }
         }
     }
     val partsEnvelope = Envelope {
-        parts(TaggedEnvelopeFormat, envelopes)
+        multipart(TaggedEnvelopeFormat, envelopes)
     }
 
     @Test
     fun testParts() {
-        val bytes = TaggedEnvelopeFormat.default.writeBytes(partsEnvelope)
-        val reconstructed = TaggedEnvelopeFormat.default.readBytes(bytes)
-        val parts = reconstructed.parts().toList()
+        val bytes = TaggedEnvelopeFormat.writeBytes(partsEnvelope)
+        val reconstructed = TaggedEnvelopeFormat.readBytes(bytes)
+        val parts = reconstructed.parts()?.toList() ?: emptyList()
         assertEquals(2, parts[2].meta["value"].int)
+        println(reconstructed.data!!.size)
     }
 
 }
\ No newline at end of file
diff --git a/dataforge-io/src/jvmMain/kotlin/hep/dataforge/io/FileEnvelope.kt b/dataforge-io/src/jvmMain/kotlin/hep/dataforge/io/FileEnvelope.kt
index 3187cd54..5f21e6ae 100644
--- a/dataforge-io/src/jvmMain/kotlin/hep/dataforge/io/FileEnvelope.kt
+++ b/dataforge-io/src/jvmMain/kotlin/hep/dataforge/io/FileEnvelope.kt
@@ -1,9 +1,7 @@
 package hep.dataforge.io
 
-import hep.dataforge.meta.EmptyMeta
 import hep.dataforge.meta.Meta
 import kotlinx.io.nio.asInput
-import kotlinx.io.nio.asOutput
 import java.nio.file.Files
 import java.nio.file.Path
 import java.nio.file.StandardOpenOption
@@ -15,7 +13,7 @@ class FileEnvelope internal constructor(val path: Path, val format: EnvelopeForm
 
     init {
         val input = Files.newByteChannel(path, StandardOpenOption.READ).asInput()
-        partialEnvelope = format.run { input.use { it.readPartial()} }
+        partialEnvelope = format.run { input.use { it.readPartial() } }
     }
 
     override val meta: Meta get() = partialEnvelope.meta
@@ -23,30 +21,3 @@ class FileEnvelope internal constructor(val path: Path, val format: EnvelopeForm
     override val data: Binary? = FileBinary(path, partialEnvelope.dataOffset, partialEnvelope.dataSize)
 }
 
-fun IOPlugin.readEnvelopeFile(
-    path: Path,
-    formatFactory: EnvelopeFormatFactory = TaggedEnvelopeFormat,
-    formatMeta: Meta = EmptyMeta
-): FileEnvelope {
-    val format = formatFactory(formatMeta, context)
-    return FileEnvelope(path, format)
-}
-
-fun IOPlugin.writeEnvelopeFile(
-    path: Path,
-    envelope: Envelope,
-    formatFactory: EnvelopeFormatFactory = TaggedEnvelopeFormat,
-    formatMeta: Meta = EmptyMeta
-) {
-    val output = Files.newByteChannel(
-        path,
-        StandardOpenOption.WRITE,
-        StandardOpenOption.CREATE,
-        StandardOpenOption.TRUNCATE_EXISTING
-    ).asOutput()
-
-    with(formatFactory(formatMeta, context)) {
-        output.writeObject(envelope)
-    }
-}
-
diff --git a/dataforge-io/src/jvmMain/kotlin/hep/dataforge/io/fileIO.kt b/dataforge-io/src/jvmMain/kotlin/hep/dataforge/io/fileIO.kt
new file mode 100644
index 00000000..14e4c077
--- /dev/null
+++ b/dataforge-io/src/jvmMain/kotlin/hep/dataforge/io/fileIO.kt
@@ -0,0 +1,137 @@
+package hep.dataforge.io
+
+import hep.dataforge.descriptors.NodeDescriptor
+import hep.dataforge.meta.DFExperimental
+import hep.dataforge.meta.EmptyMeta
+import hep.dataforge.meta.Meta
+import kotlinx.io.nio.asInput
+import kotlinx.io.nio.asOutput
+import java.nio.file.Files
+import java.nio.file.Path
+import java.nio.file.StandardOpenOption
+import kotlin.reflect.full.isSuperclassOf
+import kotlin.streams.asSequence
+
+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
+ */
+fun IOPlugin.readMetaFile(path: Path, formatOverride: MetaFormat? = null, descriptor: NodeDescriptor? = null): Meta {
+    if (!Files.exists(path)) error("Meta file $path does not exist")
+
+    val actualPath: Path = if (Files.isDirectory(path)) {
+        Files.list(path).asSequence().find { it.fileName.startsWith("meta") }
+            ?: error("The directory $path does not contain meta file")
+    } else {
+        path
+    }
+    val extension = actualPath.fileName.toString().substringAfterLast('.')
+
+    val metaFormat = formatOverride ?: metaFormat(extension) ?: error("Can't resolve meta format $extension")
+    return metaFormat.run {
+        Files.newByteChannel(actualPath, StandardOpenOption.READ).asInput().use { it.readMeta(descriptor) }
+    }
+}
+
+/**
+ * Write meta to file using [metaFormat]. If [path] is a directory, write a file with name equals name of [metaFormat].
+ * Like "meta.json"
+ */
+fun IOPlugin.writeMetaFile(
+    path: Path,
+    metaFormat: MetaFormatFactory = JsonMetaFormat,
+    descriptor: NodeDescriptor? = null
+) {
+    val actualPath = if (Files.isDirectory(path)) {
+        path.resolve(metaFormat.name.toString())
+    } else {
+        path
+    }
+    metaFormat.run {
+        Files.newByteChannel(actualPath, StandardOpenOption.WRITE, StandardOpenOption.CREATE_NEW).asOutput().use {
+            it.writeMeta(meta, descriptor)
+        }
+    }
+}
+
+/**
+ * Read and envelope from file if the file exists, return null if file does not exist.
+ *
+ * If file is directory, then expect two files inside:
+ * * **meta.<format name>** for meta
+ * * **data** for data
+ *
+ * If the file is envelope read it using [EnvelopeFormatFactory.peekFormat] functionality to infer format.
+ *
+ * If the file is not an envelope and [readNonEnvelopes] is true, return an Envelope without meta, using file as binary.
+ *
+ * Return null otherwise.
+ */
+@DFExperimental
+fun IOPlugin.readEnvelopeFile(path: Path, readNonEnvelopes: Boolean = false): 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") }
+
+        val meta = if (metaFile == null) {
+            EmptyMeta
+        } else {
+            readMetaFile(metaFile)
+        }
+
+        val dataFile = path.resolve("data")
+
+        val data: Binary? = if (Files.exists(dataFile)) {
+            dataFile.asBinary()
+        } else {
+            null
+        }
+
+        return SimpleEnvelope(meta, data)
+    }
+
+    val binary = path.asBinary()
+
+    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")
+    }
+}
+
+fun IOPlugin.writeEnvelopeFile(
+    path: Path,
+    envelope: Envelope,
+    format: EnvelopeFormat = TaggedEnvelopeFormat
+) {
+    val output = Files.newByteChannel(
+        path,
+        StandardOpenOption.WRITE,
+        StandardOpenOption.CREATE,
+        StandardOpenOption.TRUNCATE_EXISTING
+    ).asOutput()
+
+    with(format) {
+        output.writeObject(envelope)
+    }
+}
\ No newline at end of file
diff --git a/dataforge-io/src/jvmMain/kotlin/hep/dataforge/io/functionsJVM.kt b/dataforge-io/src/jvmMain/kotlin/hep/dataforge/io/functionsJVM.kt
new file mode 100644
index 00000000..fae986d7
--- /dev/null
+++ b/dataforge-io/src/jvmMain/kotlin/hep/dataforge/io/functionsJVM.kt
@@ -0,0 +1,29 @@
+package hep.dataforge.io
+
+import hep.dataforge.io.functions.FunctionServer
+import hep.dataforge.io.functions.function
+import hep.dataforge.meta.Meta
+import hep.dataforge.meta.buildMeta
+import hep.dataforge.names.Name
+import kotlin.reflect.KClass
+import kotlin.reflect.full.isSuperclassOf
+
+
+fun IOPlugin.resolveIOFormatName(type: KClass<*>): Name {
+    return ioFormats.entries.find { it.value.type.isSuperclassOf(type) }?.key
+        ?: error("Can't resolve IOFormat for type $type")
+}
+
+inline fun <reified T : Any, reified R : Any> IOPlugin.generateFunctionMeta(functionName: String): Meta = buildMeta {
+    FunctionServer.FUNCTION_NAME_KEY put functionName
+    FunctionServer.INPUT_FORMAT_KEY put resolveIOFormatName(T::class).toString()
+    FunctionServer.OUTPUT_FORMAT_KEY put resolveIOFormatName(R::class).toString()
+}
+
+inline fun <reified T : Any, reified R : Any> FunctionServer.function(
+    functionName: String
+): (suspend (T) -> R) {
+    val plugin = context.plugins.get<IOPlugin>() ?: error("IO plugin not loaded")
+    val meta = plugin.generateFunctionMeta<T, R>(functionName)
+    return function(meta)
+}
\ No newline at end of file
diff --git a/dataforge-io/src/jvmMain/kotlin/hep/dataforge/io/ioFormatsJVM.kt b/dataforge-io/src/jvmMain/kotlin/hep/dataforge/io/ioFormatsJVM.kt
deleted file mode 100644
index c926d07a..00000000
--- a/dataforge-io/src/jvmMain/kotlin/hep/dataforge/io/ioFormatsJVM.kt
+++ /dev/null
@@ -1,51 +0,0 @@
-package hep.dataforge.io
-
-import hep.dataforge.descriptors.NodeDescriptor
-import hep.dataforge.io.functions.FunctionServer
-import hep.dataforge.io.functions.FunctionServer.Companion.FUNCTION_NAME_KEY
-import hep.dataforge.io.functions.FunctionServer.Companion.INPUT_FORMAT_KEY
-import hep.dataforge.io.functions.FunctionServer.Companion.OUTPUT_FORMAT_KEY
-import hep.dataforge.io.functions.function
-import hep.dataforge.meta.Meta
-import hep.dataforge.meta.buildMeta
-import hep.dataforge.names.Name
-import kotlinx.io.nio.asOutput
-import java.nio.file.Files
-import java.nio.file.Path
-import java.nio.file.StandardOpenOption
-import kotlin.reflect.KClass
-import kotlin.reflect.full.isSuperclassOf
-
-inline fun <reified T : Any> IOPlugin.resolveIOFormat(): IOFormat<T>? {
-    return ioFormats.values.find { it.type.isSuperclassOf(T::class) } as IOFormat<T>?
-}
-
-fun IOPlugin.resolveIOFormatName(type: KClass<*>): Name {
-    return ioFormats.entries.find { it.value.type.isSuperclassOf(type) }?.key
-        ?: error("Can't resolve IOFormat for type $type")
-}
-
-inline fun <reified T : Any, reified R : Any> IOPlugin.generateFunctionMeta(functionName: String): Meta = buildMeta {
-    FUNCTION_NAME_KEY put functionName
-    INPUT_FORMAT_KEY put resolveIOFormatName(T::class).toString()
-    OUTPUT_FORMAT_KEY put resolveIOFormatName(R::class).toString()
-}
-
-inline fun <reified T : Any, reified R : Any> FunctionServer.function(
-    functionName: String
-): (suspend (T) -> R) {
-    val plugin = context.plugins.get<IOPlugin>() ?: error("IO plugin not loaded")
-    val meta = plugin.generateFunctionMeta<T, R>(functionName)
-    return function(meta)
-}
-
-/**
- * Write meta to file in a given [format]
- */
-fun Meta.write(path: Path, format: MetaFormat, descriptor: NodeDescriptor? = null) {
-    format.run {
-        Files.newByteChannel(path, StandardOpenOption.WRITE, StandardOpenOption.CREATE_NEW)
-            .asOutput()
-            .writeMeta(this@write, descriptor)
-    }
-}
\ No newline at end of file
diff --git a/dataforge-io/src/jvmMain/kotlin/hep/dataforge/io/tcp/InputStreamAsInput.kt b/dataforge-io/src/jvmMain/kotlin/hep/dataforge/io/tcp/InputStreamAsInput.kt
index 1c711be0..eb743625 100644
--- a/dataforge-io/src/jvmMain/kotlin/hep/dataforge/io/tcp/InputStreamAsInput.kt
+++ b/dataforge-io/src/jvmMain/kotlin/hep/dataforge/io/tcp/InputStreamAsInput.kt
@@ -3,7 +3,6 @@ package hep.dataforge.io.tcp
 import kotlinx.io.core.AbstractInput
 import kotlinx.io.core.Input
 import kotlinx.io.core.IoBuffer
-import kotlinx.io.core.IoBuffer.Companion.NoPool
 import kotlinx.io.core.writePacket
 import kotlinx.io.streams.readPacketAtMost
 import java.io.InputStream
@@ -13,7 +12,7 @@ import java.io.InputStream
  */
 internal class InputStreamAsInput(
     private val stream: InputStream
-) : AbstractInput(pool = NoPool) {
+) : AbstractInput(pool = IoBuffer.Pool) {
 
 
     override fun fill(): IoBuffer? {
diff --git a/dataforge-io/src/jvmTest/kotlin/hep/dataforge/io/FileBinaryTest.kt b/dataforge-io/src/jvmTest/kotlin/hep/dataforge/io/FileBinaryTest.kt
index 94403dcd..d8c7c67a 100644
--- a/dataforge-io/src/jvmTest/kotlin/hep/dataforge/io/FileBinaryTest.kt
+++ b/dataforge-io/src/jvmTest/kotlin/hep/dataforge/io/FileBinaryTest.kt
@@ -39,7 +39,7 @@ class FileBinaryTest {
         }
         val binary = envelopeFromFile.data!!
         println(binary.toBytes().size)
-        assertEquals(binary.size.toInt(), binary.toBytes().size)
+        assertEquals(binary.size?.toInt(), binary.toBytes().size)
 
     }
 
@@ -49,7 +49,7 @@ class FileBinaryTest {
         val tmpPath = Files.createTempFile("dataforge_test", ".df")
         Global.io.writeEnvelopeFile(tmpPath, envelope)
 
-        val binary = Global.io.readEnvelopeFile(tmpPath).data!!
+        val binary = Global.io.readEnvelopeFile(tmpPath)?.data!!
         assertEquals(binary.size.toInt(), binary.toBytes().size)
     }
 
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 33c07f66..ea67fffd 100644
--- a/dataforge-io/src/jvmTest/kotlin/hep/dataforge/io/FileEnvelopeTest.kt
+++ b/dataforge-io/src/jvmTest/kotlin/hep/dataforge/io/FileEnvelopeTest.kt
@@ -29,7 +29,7 @@ class FileEnvelopeTest {
         val tmpPath = Files.createTempFile("dataforge_test", ".df")
         Global.io.writeEnvelopeFile(tmpPath,envelope)
         println(tmpPath.toUri())
-        val restored: Envelope = Global.io.readEnvelopeFile(tmpPath)
+        val restored: Envelope = Global.io.readEnvelopeFile(tmpPath)!!
         assertTrue { envelope.contentEquals(restored) }
     }
 
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 a483c78b..b5ecb519 100644
--- a/dataforge-workspace/src/jvmMain/kotlin/hep/dataforge/workspace/fileData.kt
+++ b/dataforge-workspace/src/jvmMain/kotlin/hep/dataforge/workspace/fileData.kt
@@ -1,93 +1,47 @@
 package hep.dataforge.workspace
 
-import hep.dataforge.data.Data
-import hep.dataforge.data.DataNode
-import hep.dataforge.data.DataTreeBuilder
-import hep.dataforge.data.datum
-import hep.dataforge.descriptors.NodeDescriptor
-import hep.dataforge.io.*
-import hep.dataforge.meta.EmptyMeta
+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 kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.withContext
-import kotlinx.io.nio.asInput
-import kotlinx.io.nio.asOutput
+import hep.dataforge.meta.get
+import hep.dataforge.meta.string
 import java.nio.file.Files
 import java.nio.file.Path
-import java.nio.file.StandardOpenOption
 import kotlin.reflect.KClass
 
-/**
- * Read meta from file in a given [MetaFormat]
- */
-fun MetaFormat.readMetaFile(path: Path, descriptor: NodeDescriptor? = null): Meta {
-    return Files.newByteChannel(path, StandardOpenOption.READ)
-        .asInput()
-        .readMeta(descriptor)
-}
-
-/**
- * Write meta to file using given [MetaFormat]
- */
-fun MetaFormat.writeMetaFile(path: Path, meta: Meta, descriptor: NodeDescriptor? = null) {
-    return Files.newByteChannel(path, StandardOpenOption.WRITE, StandardOpenOption.CREATE_NEW)
-        .asOutput()
-        .writeMeta(meta, descriptor)
-}
 
 /**
  * Read data with supported envelope format and binary format. If envelope format is null, then read binary directly from file.
  * The operation is blocking since it must read meta header. The reading of envelope body is lazy
  * @param type explicit type of data read
  * @param dataFormat binary format
- * @param envelopeFormatFactory the format of envelope. If null, file is read directly
+ * @param envelopeFormat the format of envelope. If null, file is read directly
  * @param metaFile the relative file for optional meta override
  * @param metaFileFormat the meta format for override
  */
-fun <T : Any> IOPlugin.readData(
+fun <T : Any> IOPlugin.readDataFile(
     path: Path,
     type: KClass<out T>,
-    dataFormat: IOFormat<T>,
-    envelopeFormatFactory: EnvelopeFormatFactory? = null,
-    metaFile: Path = path.resolveSibling("${path.fileName}.meta"),
-    metaFileFormat: MetaFormat = JsonMetaFormat.default
+    formatResolver: (Meta) -> IOFormat<T>
 ): Data<T> {
-    val externalMeta = if (Files.exists(metaFile)) {
-        metaFileFormat.readMetaFile(metaFile)
-    } else {
-        null
-    }
-    return if (envelopeFormatFactory == null) {
-        Data(type, externalMeta ?: EmptyMeta) {
-            withContext(Dispatchers.IO) {
-                dataFormat.run {
-                    Files.newByteChannel(path, StandardOpenOption.READ)
-                        .asInput()
-                        .readObject()
-                }
-            }
-        }
-    } else {
-        readEnvelopeFile(path, envelopeFormatFactory).let {
-            if (externalMeta == null) {
-                it
-            } else {
-                it.withMetaLayers(externalMeta)
-            }
-        }.toData(type, dataFormat)
-    }
+    val envelope = readEnvelopeFile(path, true) ?: error("Can't read data from $path")
+    val format = formatResolver(envelope.meta)
+    return envelope.toData(type, format)
 }
 
 //TODO wants multi-receiver
 fun <T : Any> DataTreeBuilder<T>.file(
     plugin: IOPlugin,
     path: Path,
-    dataFormat: IOFormat<T>,
-    envelopeFormatFactory: EnvelopeFormatFactory? = null
+    formatResolver: (Meta) -> IOFormat<T>
 ) {
     plugin.run {
-        val data = readData(path, type, dataFormat, envelopeFormatFactory)
-        val name = path.fileName.toString().replace(".df", "")
+        val data = readDataFile(path, type, formatResolver)
+        val name = data.meta[Envelope.ENVELOPE_NAME_KEY].string
+            ?: path.fileName.toString().replace(".df", "")
         datum(name, data)
     }
 }
@@ -95,23 +49,35 @@ fun <T : Any> DataTreeBuilder<T>.file(
 /**
  * Read the directory as a data node
  */
-fun <T : Any> IOPlugin.readDataNode(
+fun <T : Any> IOPlugin.readDataDirectory(
     path: Path,
     type: KClass<out T>,
-    dataFormat: IOFormat<T>,
-    envelopeFormatFactory: EnvelopeFormatFactory? = null
+    formatResolver: (Meta) -> IOFormat<T>
 ): DataNode<T> {
     if (!Files.isDirectory(path)) error("Provided path $this is not a directory")
     return DataNode(type) {
         Files.list(path).forEach { path ->
             if (!path.fileName.toString().endsWith(".meta")) {
-                file(this@readDataNode,path, dataFormat, envelopeFormatFactory)
+                file(this@readDataDirectory, path, formatResolver)
             }
         }
     }
 }
 
-//suspend fun <T : Any> Path.writeData(
-//    data: Data<T>,
-//    format: IOFormat<T>,
-//    )
\ No newline at end of file
+fun <T : Any> DataTreeBuilder<T>.directory(
+    plugin: IOPlugin,
+    path: Path,
+    formatResolver: (Meta) -> IOFormat<T>
+) {
+    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)
+    }
+}
+
+
+
+
+