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 14d871db..c9d32c9f 100644
--- a/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/TaglessEnvelopeFormat.kt
+++ b/dataforge-io/src/commonMain/kotlin/hep/dataforge/io/TaglessEnvelopeFormat.kt
@@ -43,6 +43,7 @@ class TaglessEnvelopeFormat(
             writeText(dataStart + "\r\n")
             writeFully(data.toBytes())
         }
+        flush()
     }
 
     override fun Input.readObject(): Envelope {
diff --git a/dataforge-io/src/jvmTest/kotlin/hep/dataforge/io/BinaryTest.kt b/dataforge-io/src/jvmTest/kotlin/hep/dataforge/io/BinaryTest.kt
new file mode 100644
index 00000000..f7018e5e
--- /dev/null
+++ b/dataforge-io/src/jvmTest/kotlin/hep/dataforge/io/BinaryTest.kt
@@ -0,0 +1,82 @@
+package hep.dataforge.io
+
+import hep.dataforge.context.Global
+import kotlinx.io.core.readAvailable
+import org.junit.Test
+import java.nio.file.Files
+import java.nio.file.Paths
+import kotlin.test.assertEquals
+import kotlin.test.assertTrue
+
+class BinaryTest {
+    val envelope = Envelope {
+        meta {
+            "a" put "AAA"
+            "b" put 22.2
+        }
+        dataType = "hep.dataforge.test"
+        dataID = "myData" // добавил только что
+        data {
+            writeDouble(16.7)
+
+        }
+    }
+
+    @Test
+    fun testSize() {
+        val binary = envelope.data!!
+        assertEquals(binary.size.toInt(), binary.toBytes().size)
+    }
+
+
+    val envelopeFromFile = Envelope {
+        meta {
+            "a" put "AAA"
+            "b" put 22.2
+        }
+        dataType = "hep.dataforge.satellite"
+        dataID = "cellDepositTest" // добавил только что
+        this@Envelope.data = Paths.get("test_data", "binaryBlock.bin").asBinary()
+    }
+
+    @Test
+    fun testFileDataSize() {
+        println(System.getProperty("user.dir"))
+        val binary = envelopeFromFile.data!!
+        println(binary.toBytes().size)
+        assertEquals(binary.size.toInt(), binary.toBytes().size)
+    }
+
+    @Test
+    fun testFileDataSizeRewriting() {
+        println(System.getProperty("user.dir"))
+        val tmpPath = Files.createTempFile("dataforge_test", ".df")
+        Global.io.writeEnvelopeFile(tmpPath, envelopeFromFile)
+
+        val binary = Global.io.readEnvelopeFile(tmpPath).data!!
+        assertEquals(binary.size.toInt(), binary.toBytes().size)
+    }
+
+    @Test
+    fun testDataReading() {
+        println(System.getProperty("user.dir"))
+        val tmpPath = Files.createTempFile("dataforge_test", ".df")
+        Global.io.writeEnvelopeFile(tmpPath, envelopeFromFile)
+
+        val binary = Global.io.readEnvelopeFile(tmpPath).data!!
+
+        var sum = 0.0
+        binary.read {
+            val dst = DoubleArray(100) { 0.0 }
+            do {
+                val flag = readAvailable(dst)
+                println("$flag : ${dst[0]}")
+                dst.map {
+                    sum += it
+                }
+            } while (flag != -1)
+        }
+        assertTrue(sum > 0.0)
+    }
+
+}
\ 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 ba7f7cc5..0c934d80 100644
--- a/dataforge-io/src/jvmTest/kotlin/hep/dataforge/io/FileEnvelopeTest.kt
+++ b/dataforge-io/src/jvmTest/kotlin/hep/dataforge/io/FileEnvelopeTest.kt
@@ -1,9 +1,10 @@
 package hep.dataforge.io
 
 import hep.dataforge.context.Global
+import java.nio.ByteBuffer
 import java.nio.file.Files
-import kotlin.test.Test
-import kotlin.test.assertTrue
+import java.util.*
+import kotlin.test.*
 
 
 class FileEnvelopeTest {
@@ -21,11 +22,66 @@ class FileEnvelopeTest {
     }
 
     @Test
-    fun testFileWriteRead() {
+    fun testFileWriteTagged() {
+        val tmpPath = Files.createTempFile("dataforge_test", ".df")
+        Global.io.writeEnvelopeFile(tmpPath, envelope)
+        assertTrue { tmpPath.toFile().length() > 0 }
+    }
+
+    @Test
+    fun testFileWriteReadTagged() {
         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) }
     }
+
+    @Test
+    fun testFileWriteTagless() {
+        val tmpPath = Files.createTempFile("dataforge_test", ".df")
+        Global.io.writeEnvelopeFile(tmpPath, envelope, formatFactory = TaglessEnvelopeFormat)
+        assertTrue { tmpPath.toFile().length() > 0 }
+    }
+
+    @Test
+    fun testFileWriteReadTagless() {
+        val tmpPath = Files.createTempFile("dataforge_test", ".df")
+        Global.io.writeEnvelopeFile(tmpPath, envelope, formatFactory = TaglessEnvelopeFormat)
+        println(tmpPath.toUri())
+        val restored: Envelope = Global.io.readEnvelopeFile(tmpPath, formatFactory = TaglessEnvelopeFormat)
+        assertTrue { envelope.contentEquals(restored) }
+    }
+
+
+    @Test
+    fun testDataSize() {
+        val tmpPath = Files.createTempFile("dataforge_test", ".df")
+        Global.io.writeEnvelopeFile(tmpPath,envelope)
+        println(tmpPath.toUri())
+        val scan = Scanner(tmpPath.toFile().inputStream()).useDelimiter("\n").nextLine()
+        println(scan)
+        val format = scan.slice(2..5)
+        when(format){
+            "DF03" -> {
+                val buff = ByteBuffer.allocate(4)
+                buff.put(scan.slice(12..19).toByteArray())
+                buff.flip()
+                val size = buff.long
+                println(size)
+                assertEquals(8, size)
+            }
+            "DF02" -> {
+                val buff = ByteBuffer.allocate(4)
+                buff.put(scan.slice(12..15).toByteArray())
+                buff.flip()
+                val size = buff.int
+                println(size)
+                assertEquals(8, size)
+            }
+            else -> {
+                fail("Format $format don't have test")
+            }
+        }
+    }
 }
\ No newline at end of file
diff --git a/dataforge-io/test_data/binaryBlock.bin b/dataforge-io/test_data/binaryBlock.bin
new file mode 100644
index 00000000..557584c4
Binary files /dev/null and b/dataforge-io/test_data/binaryBlock.bin differ