diff --git a/lucene/core/src/java/org/apache/lucene/codecs/lucene40/Lucene40StoredFieldsFormat.java b/lucene/core/src/java/org/apache/lucene/codecs/lucene40/Lucene40StoredFieldsFormat.java
index 240d16d..32b03e5 100644
--- a/lucene/core/src/java/org/apache/lucene/codecs/lucene40/Lucene40StoredFieldsFormat.java
+++ b/lucene/core/src/java/org/apache/lucene/codecs/lucene40/Lucene40StoredFieldsFormat.java
@@ -28,6 +28,7 @@ import org.apache.lucene.index.SegmentInfo;
 import org.apache.lucene.store.DataOutput; // javadocs
 import org.apache.lucene.store.Directory;
 import org.apache.lucene.store.IOContext;
+import org.apache.lucene.util.CodecUtil;
 
 /** 
  * Lucene 4.0 Stored Fields Format.
@@ -42,7 +43,8 @@ import org.apache.lucene.store.IOContext;
  * <p>This contains, for each document, a pointer to its field data, as
  * follows:</p>
  * <ul>
- * <li>FieldIndex (.fdx) --&gt; &lt;FieldValuesPosition&gt; <sup>SegSize</sup></li>
+ * <li>FieldIndex (.fdx) --&gt; &lt;Header&gt;, &lt;FieldValuesPosition&gt; <sup>SegSize</sup></li>
+ * <li>Header --&gt; {@link CodecUtil#writeHeader CodecHeader}</li>
  * <li>FieldValuesPosition --&gt; {@link DataOutput#writeLong Uint64}</li>
  * </ul>
  * </li>
@@ -50,7 +52,8 @@ import org.apache.lucene.store.IOContext;
  * <p><a name="field_data" id="field_data"></a>The field data, or <tt>.fdt</tt> file.</p>
  * <p>This contains the stored fields of each document, as follows:</p>
  * <ul>
- * <li>FieldData (.fdt) --&gt; &lt;DocFieldData&gt; <sup>SegSize</sup></li>
+ * <li>FieldData (.fdt) --&gt; &lt;Header&gt;, &lt;DocFieldData&gt; <sup>SegSize</sup></li>
+ * <li>Header --&gt; {@link CodecUtil#writeHeader CodecHeader}</li>
  * <li>DocFieldData --&gt; FieldCount, &lt;FieldNum, Bits, Value&gt;
  * <sup>FieldCount</sup></li>
  * <li>FieldCount --&gt; {@link DataOutput#writeVInt VInt}</li>
diff --git a/lucene/core/src/java/org/apache/lucene/codecs/lucene40/Lucene40StoredFieldsReader.java b/lucene/core/src/java/org/apache/lucene/codecs/lucene40/Lucene40StoredFieldsReader.java
index ab89821..99cfe4f 100644
--- a/lucene/core/src/java/org/apache/lucene/codecs/lucene40/Lucene40StoredFieldsReader.java
+++ b/lucene/core/src/java/org/apache/lucene/codecs/lucene40/Lucene40StoredFieldsReader.java
@@ -30,11 +30,14 @@ import org.apache.lucene.store.AlreadyClosedException;
 import org.apache.lucene.store.Directory;
 import org.apache.lucene.store.IOContext;
 import org.apache.lucene.store.IndexInput;
+import org.apache.lucene.util.CodecUtil;
 import org.apache.lucene.util.IOUtils;
 
 import java.io.Closeable;
 import java.util.Set;
 
+import static org.apache.lucene.codecs.lucene40.Lucene40StoredFieldsWriter.*;
+
 /**
  * Class responsible for access to stored document fields.
  * <p/>
@@ -44,8 +47,6 @@ import java.util.Set;
  * @lucene.internal
  */
 public final class Lucene40StoredFieldsReader extends StoredFieldsReader implements Cloneable, Closeable {
-  private final static int FORMAT_SIZE = 4;
-
   private final FieldInfos fieldInfos;
   private final IndexInput fieldsStream;
   private final IndexInput indexStream;
@@ -78,17 +79,15 @@ public final class Lucene40StoredFieldsReader extends StoredFieldsReader impleme
     boolean success = false;
     fieldInfos = fn;
     try {
-      fieldsStream = d.openInput(IndexFileNames.segmentFileName(segment, "", Lucene40StoredFieldsWriter.FIELDS_EXTENSION), context);
-      final String indexStreamFN = IndexFileNames.segmentFileName(segment, "", Lucene40StoredFieldsWriter.FIELDS_INDEX_EXTENSION);
+      fieldsStream = d.openInput(IndexFileNames.segmentFileName(segment, "", FIELDS_EXTENSION), context);
+      final String indexStreamFN = IndexFileNames.segmentFileName(segment, "", FIELDS_INDEX_EXTENSION);
       indexStream = d.openInput(indexStreamFN, context);
       
-      // its a 4.0 codec: so its not too-old, its corrupt.
-      // TODO: change this to CodecUtil.checkHeader
-      if (Lucene40StoredFieldsWriter.FORMAT_CURRENT != indexStream.readInt()) {
-        throw new CorruptIndexException("unexpected fdx header: " + indexStream);
-      }
-
-      final long indexSize = indexStream.length() - FORMAT_SIZE;
+      CodecUtil.checkHeader(indexStream, CODEC_NAME_IDX, VERSION_START, VERSION_CURRENT);
+      CodecUtil.checkHeader(fieldsStream, CODEC_NAME_DAT, VERSION_START, VERSION_CURRENT);
+      assert HEADER_LENGTH_DAT == fieldsStream.getFilePointer();
+      assert HEADER_LENGTH_IDX == indexStream.getFilePointer();
+      final long indexSize = indexStream.length() - HEADER_LENGTH_IDX;
       this.size = (int) (indexSize >> 3);
       // Verify two sources of "maxDoc" agree:
       if (this.size != si.docCount) {
@@ -135,7 +134,7 @@ public final class Lucene40StoredFieldsReader extends StoredFieldsReader impleme
   }
 
   private void seekIndex(int docID) throws IOException {
-    indexStream.seek(FORMAT_SIZE + docID * 8L);
+    indexStream.seek(HEADER_LENGTH_IDX + docID * 8L);
   }
 
   public final void visitDocument(int n, StoredFieldVisitor visitor) throws CorruptIndexException, IOException {
@@ -148,7 +147,7 @@ public final class Lucene40StoredFieldsReader extends StoredFieldsReader impleme
       FieldInfo fieldInfo = fieldInfos.fieldInfo(fieldNumber);
       
       int bits = fieldsStream.readByte() & 0xFF;
-      assert bits <= (Lucene40StoredFieldsWriter.FIELD_IS_NUMERIC_MASK | Lucene40StoredFieldsWriter.FIELD_IS_BINARY): "bits=" + Integer.toHexString(bits);
+      assert bits <= (FIELD_IS_NUMERIC_MASK | FIELD_IS_BINARY): "bits=" + Integer.toHexString(bits);
 
       switch(visitor.needsField(fieldInfo)) {
         case YES:
@@ -164,19 +163,19 @@ public final class Lucene40StoredFieldsReader extends StoredFieldsReader impleme
   }
 
   private void readField(StoredFieldVisitor visitor, FieldInfo info, int bits) throws IOException {
-    final int numeric = bits & Lucene40StoredFieldsWriter.FIELD_IS_NUMERIC_MASK;
+    final int numeric = bits & FIELD_IS_NUMERIC_MASK;
     if (numeric != 0) {
       switch(numeric) {
-        case Lucene40StoredFieldsWriter.FIELD_IS_NUMERIC_INT:
+        case FIELD_IS_NUMERIC_INT:
           visitor.intField(info, fieldsStream.readInt());
           return;
-        case Lucene40StoredFieldsWriter.FIELD_IS_NUMERIC_LONG:
+        case FIELD_IS_NUMERIC_LONG:
           visitor.longField(info, fieldsStream.readLong());
           return;
-        case Lucene40StoredFieldsWriter.FIELD_IS_NUMERIC_FLOAT:
+        case FIELD_IS_NUMERIC_FLOAT:
           visitor.floatField(info, Float.intBitsToFloat(fieldsStream.readInt()));
           return;
-        case Lucene40StoredFieldsWriter.FIELD_IS_NUMERIC_DOUBLE:
+        case FIELD_IS_NUMERIC_DOUBLE:
           visitor.doubleField(info, Double.longBitsToDouble(fieldsStream.readLong()));
           return;
         default:
@@ -186,7 +185,7 @@ public final class Lucene40StoredFieldsReader extends StoredFieldsReader impleme
       final int length = fieldsStream.readVInt();
       byte bytes[] = new byte[length];
       fieldsStream.readBytes(bytes, 0, length);
-      if ((bits & Lucene40StoredFieldsWriter.FIELD_IS_BINARY) != 0) {
+      if ((bits & FIELD_IS_BINARY) != 0) {
         visitor.binaryField(info, bytes, 0, bytes.length);
       } else {
         visitor.stringField(info, new String(bytes, 0, bytes.length, IOUtils.CHARSET_UTF_8));
@@ -195,15 +194,15 @@ public final class Lucene40StoredFieldsReader extends StoredFieldsReader impleme
   }
   
   private void skipField(int bits) throws IOException {
-    final int numeric = bits & Lucene40StoredFieldsWriter.FIELD_IS_NUMERIC_MASK;
+    final int numeric = bits & FIELD_IS_NUMERIC_MASK;
     if (numeric != 0) {
       switch(numeric) {
-        case Lucene40StoredFieldsWriter.FIELD_IS_NUMERIC_INT:
-        case Lucene40StoredFieldsWriter.FIELD_IS_NUMERIC_FLOAT:
+        case FIELD_IS_NUMERIC_INT:
+        case FIELD_IS_NUMERIC_FLOAT:
           fieldsStream.readInt();
           return;
-        case Lucene40StoredFieldsWriter.FIELD_IS_NUMERIC_LONG:
-        case Lucene40StoredFieldsWriter.FIELD_IS_NUMERIC_DOUBLE:
+        case FIELD_IS_NUMERIC_LONG:
+        case FIELD_IS_NUMERIC_DOUBLE:
           fieldsStream.readLong();
           return;
         default: 
@@ -242,7 +241,7 @@ public final class Lucene40StoredFieldsReader extends StoredFieldsReader impleme
   }
 
   public static void files(SegmentInfo info, Set<String> files) throws IOException {
-    files.add(IndexFileNames.segmentFileName(info.name, "", Lucene40StoredFieldsWriter.FIELDS_INDEX_EXTENSION));
-    files.add(IndexFileNames.segmentFileName(info.name, "", Lucene40StoredFieldsWriter.FIELDS_EXTENSION));
+    files.add(IndexFileNames.segmentFileName(info.name, "", FIELDS_INDEX_EXTENSION));
+    files.add(IndexFileNames.segmentFileName(info.name, "", FIELDS_EXTENSION));
   }
 }
diff --git a/lucene/core/src/java/org/apache/lucene/codecs/lucene40/Lucene40StoredFieldsWriter.java b/lucene/core/src/java/org/apache/lucene/codecs/lucene40/Lucene40StoredFieldsWriter.java
index c236d9c..15f2ea5 100644
--- a/lucene/core/src/java/org/apache/lucene/codecs/lucene40/Lucene40StoredFieldsWriter.java
+++ b/lucene/core/src/java/org/apache/lucene/codecs/lucene40/Lucene40StoredFieldsWriter.java
@@ -34,6 +34,7 @@ import org.apache.lucene.store.IndexInput;
 import org.apache.lucene.store.IndexOutput;
 import org.apache.lucene.util.Bits;
 import org.apache.lucene.util.BytesRef;
+import org.apache.lucene.util.CodecUtil;
 import org.apache.lucene.util.IOUtils;
 
 /** 
@@ -62,16 +63,14 @@ public final class Lucene40StoredFieldsWriter extends StoredFieldsWriter {
   // currently unused: static final int FIELD_IS_NUMERIC_SHORT = 5 << _NUMERIC_BIT_SHIFT;
   // currently unused: static final int FIELD_IS_NUMERIC_BYTE = 6 << _NUMERIC_BIT_SHIFT;
 
-  // (Happens to be the same as for now) Lucene 3.2: NumericFields are stored in binary format
-  static final int FORMAT_LUCENE_3_2_NUMERIC_FIELDS = 3;
+  static final String CODEC_NAME_IDX = "Lucene40StoredFieldsIndex";
+  static final String CODEC_NAME_DAT = "Lucene40StoredFieldsData";
+  static final int VERSION_START = 0;
+  static final int VERSION_CURRENT = VERSION_START;
+  static final long HEADER_LENGTH_IDX = CodecUtil.headerLength(CODEC_NAME_IDX);
+  static final long HEADER_LENGTH_DAT = CodecUtil.headerLength(CODEC_NAME_DAT);
 
-  // NOTE: if you introduce a new format, make it 1 higher
-  // than the current one, and always change this if you
-  // switch to a new format!
-  static final int FORMAT_CURRENT = FORMAT_LUCENE_3_2_NUMERIC_FIELDS;
 
-  // when removing support for old versions, leave the last supported version here
-  static final int FORMAT_MINIMUM = FORMAT_LUCENE_3_2_NUMERIC_FIELDS;
 
   /** Extension of stored fields file */
   public static final String FIELDS_EXTENSION = "fdt";
@@ -94,9 +93,10 @@ public final class Lucene40StoredFieldsWriter extends StoredFieldsWriter {
       fieldsStream = directory.createOutput(IndexFileNames.segmentFileName(segment, "", FIELDS_EXTENSION), context);
       indexStream = directory.createOutput(IndexFileNames.segmentFileName(segment, "", FIELDS_INDEX_EXTENSION), context);
 
-      fieldsStream.writeInt(FORMAT_CURRENT);
-      indexStream.writeInt(FORMAT_CURRENT);
-
+      CodecUtil.writeHeader(fieldsStream, CODEC_NAME_DAT, VERSION_CURRENT);
+      CodecUtil.writeHeader(indexStream, CODEC_NAME_IDX, VERSION_CURRENT);
+      assert HEADER_LENGTH_DAT == fieldsStream.getFilePointer();
+      assert HEADER_LENGTH_IDX == indexStream.getFilePointer();
       success = true;
     } finally {
       if (!success) {
@@ -209,7 +209,7 @@ public final class Lucene40StoredFieldsWriter extends StoredFieldsWriter {
 
   @Override
   public void finish(int numDocs) throws IOException {
-    if (4+((long) numDocs)*8 != indexStream.getFilePointer())
+    if (HEADER_LENGTH_IDX+((long) numDocs)*8 != indexStream.getFilePointer())
       // This is most likely a bug in Sun JRE 1.6.0_04/_05;
       // we detect that the bug has struck, here, and
       // throw an exception to prevent the corruption from
diff --git a/lucene/core/src/java/org/apache/lucene/codecs/lucene40/Lucene40TermVectorsFormat.java b/lucene/core/src/java/org/apache/lucene/codecs/lucene40/Lucene40TermVectorsFormat.java
index b7fc812..54b0b55 100644
--- a/lucene/core/src/java/org/apache/lucene/codecs/lucene40/Lucene40TermVectorsFormat.java
+++ b/lucene/core/src/java/org/apache/lucene/codecs/lucene40/Lucene40TermVectorsFormat.java
@@ -28,6 +28,7 @@ import org.apache.lucene.index.SegmentInfo;
 import org.apache.lucene.store.DataOutput; // javadocs
 import org.apache.lucene.store.Directory;
 import org.apache.lucene.store.IOContext;
+import org.apache.lucene.util.CodecUtil;
 
 /**
  * Lucene 4.0 Term Vectors format.
@@ -56,7 +57,7 @@ import org.apache.lucene.store.IOContext;
  * <p>Document (.tvd) --&gt; TVDVersion&lt;NumFields, FieldNums,
  * FieldPositions&gt; <sup>NumDocs</sup></p>
  * <ul>
- *   <li>TVDVersion --&gt; {@link DataOutput#writeInt Int32} (<code>Lucene40TermVectorsReader.FORMAT_CURRENT</code>)</li>
+ *   <li>Header --&gt; {@link CodecUtil#writeHeader CodecHeader}</li>
  *   <li>NumFields --&gt; {@link DataOutput#writeVInt VInt}</li>
  *   <li>FieldNums --&gt; &lt;FieldNumDelta&gt; <sup>NumFields</sup></li>
  *   <li>FieldNumDelta --&gt; {@link DataOutput#writeVInt VInt}</li>
@@ -72,7 +73,7 @@ import org.apache.lucene.store.IOContext;
  * <p>Field (.tvf) --&gt; TVFVersion&lt;NumTerms, Position/Offset, TermFreqs&gt;
  * <sup>NumFields</sup></p>
  * <ul>
- *   <li>TVFVersion --&gt; {@link DataOutput#writeInt Int32} (<code>Lucene40TermVectorsReader.FORMAT_CURRENT</code>)</li>
+ *   <li>Header --&gt; {@link CodecUtil#writeHeader CodecHeader}</li>
  *   <li>NumTerms --&gt; {@link DataOutput#writeVInt VInt}</li>
  *   <li>Position/Offset --&gt; {@link DataOutput#writeByte Byte}</li>
  *   <li>TermFreqs --&gt; &lt;TermText, TermFreq, Positions?, Offsets?&gt;
diff --git a/lucene/core/src/java/org/apache/lucene/codecs/lucene40/Lucene40TermVectorsReader.java b/lucene/core/src/java/org/apache/lucene/codecs/lucene40/Lucene40TermVectorsReader.java
index e44713b..c0bee03 100644
--- a/lucene/core/src/java/org/apache/lucene/codecs/lucene40/Lucene40TermVectorsReader.java
+++ b/lucene/core/src/java/org/apache/lucene/codecs/lucene40/Lucene40TermVectorsReader.java
@@ -33,8 +33,6 @@ import org.apache.lucene.index.FieldInfos;
 import org.apache.lucene.index.Fields;
 import org.apache.lucene.index.FieldsEnum;
 import org.apache.lucene.index.IndexFileNames;
-import org.apache.lucene.index.IndexFormatTooNewException;
-import org.apache.lucene.index.IndexFormatTooOldException;
 import org.apache.lucene.index.SegmentInfo;
 import org.apache.lucene.index.Terms;
 import org.apache.lucene.index.TermsEnum;
@@ -43,8 +41,10 @@ import org.apache.lucene.store.IOContext;
 import org.apache.lucene.store.IndexInput;
 import org.apache.lucene.util.Bits;
 import org.apache.lucene.util.BytesRef;
+import org.apache.lucene.util.CodecUtil;
 import org.apache.lucene.util.IOUtils;
 
+
 /**
  * Lucene 4.0 Term Vectors reader.
  * <p>
@@ -54,22 +54,6 @@ import org.apache.lucene.util.IOUtils;
  */
 public class Lucene40TermVectorsReader extends TermVectorsReader {
 
-  // NOTE: if you make a new format, it must be larger than
-  // the current format
-
-  // Changed strings to UTF8 with length-in-bytes not length-in-chars
-  static final int FORMAT_UTF8_LENGTH_IN_BYTES = 4;
-
-  // NOTE: always change this if you switch to a new format!
-  // whenever you add a new format, make it 1 larger (positive version logic)!
-  static final int FORMAT_CURRENT = FORMAT_UTF8_LENGTH_IN_BYTES;
-  
-  // when removing support for old versions, leave the last supported version here
-  static final int FORMAT_MINIMUM = FORMAT_UTF8_LENGTH_IN_BYTES;
-
-  //The size in bytes that the FORMAT_VERSION will take up at the beginning of each file 
-  static final int FORMAT_SIZE = 4;
-
   static final byte STORE_POSITIONS_WITH_TERMVECTOR = 0x1;
 
   static final byte STORE_OFFSET_WITH_TERMVECTOR = 0x2;
@@ -82,6 +66,17 @@ public class Lucene40TermVectorsReader extends TermVectorsReader {
 
   /** Extension of vectors index file */
   static final String VECTORS_INDEX_EXTENSION = "tvx";
+  
+  static final String CODEC_NAME_FIELDS = "Lucene40TermVectorsFields";
+  static final String CODEC_NAME_DOCS = "Lucene40TermVectorsDocs";
+  static final String CODEC_NAME_INDEX = "Lucene40TermVectorsIndex";
+
+  static final int VERSION_START = 0;
+  static final int VERSION_CURRENT = VERSION_START;
+  
+  static final long HEADER_LENGTH_FIELDS = CodecUtil.headerLength(CODEC_NAME_FIELDS);
+  static final long HEADER_LENGTH_DOCS = CodecUtil.headerLength(CODEC_NAME_DOCS);
+  static final long HEADER_LENGTH_INDEX = CodecUtil.headerLength(CODEC_NAME_INDEX);
 
   private FieldInfos fieldInfos;
 
@@ -91,17 +86,15 @@ public class Lucene40TermVectorsReader extends TermVectorsReader {
   private int size;
   private int numTotalDocs;
   
-  private final int format;
 
   // used by clone
-  Lucene40TermVectorsReader(FieldInfos fieldInfos, IndexInput tvx, IndexInput tvd, IndexInput tvf, int size, int numTotalDocs, int format) {
+  Lucene40TermVectorsReader(FieldInfos fieldInfos, IndexInput tvx, IndexInput tvd, IndexInput tvf, int size, int numTotalDocs) {
     this.fieldInfos = fieldInfos;
     this.tvx = tvx;
     this.tvd = tvd;
     this.tvf = tvf;
     this.size = size;
     this.numTotalDocs = numTotalDocs;
-    this.format = format;
   }
     
   public Lucene40TermVectorsReader(Directory d, SegmentInfo si, FieldInfos fieldInfos, IOContext context)
@@ -114,18 +107,21 @@ public class Lucene40TermVectorsReader extends TermVectorsReader {
     try {
       String idxName = IndexFileNames.segmentFileName(segment, "", VECTORS_INDEX_EXTENSION);
       tvx = d.openInput(idxName, context);
-      format = checkValidFormat(tvx);
+      final int tvxVersion = CodecUtil.checkHeader(tvx, CODEC_NAME_INDEX, VERSION_START, VERSION_CURRENT);
+      
       String fn = IndexFileNames.segmentFileName(segment, "", VECTORS_DOCUMENTS_EXTENSION);
       tvd = d.openInput(fn, context);
-      final int tvdFormat = checkValidFormat(tvd);
+      final int tvdVersion = CodecUtil.checkHeader(tvd, CODEC_NAME_DOCS, VERSION_START, VERSION_CURRENT);
       fn = IndexFileNames.segmentFileName(segment, "", VECTORS_FIELDS_EXTENSION);
       tvf = d.openInput(fn, context);
-      final int tvfFormat = checkValidFormat(tvf);
+      final int tvfVersion = CodecUtil.checkHeader(tvf, CODEC_NAME_FIELDS, VERSION_START, VERSION_CURRENT);
+      assert HEADER_LENGTH_INDEX == tvx.getFilePointer();
+      assert HEADER_LENGTH_DOCS == tvd.getFilePointer();
+      assert HEADER_LENGTH_FIELDS == tvf.getFilePointer();
+      assert tvxVersion == tvdVersion;
+      assert tvxVersion == tvfVersion;
 
-      assert format == tvdFormat;
-      assert format == tvfFormat;
-
-      numTotalDocs = (int) (tvx.length() >> 4);
+      numTotalDocs = (int) (tvx.length()-HEADER_LENGTH_INDEX >> 4);
 
       this.size = numTotalDocs;
       assert size == 0 || numTotalDocs == size;
@@ -156,13 +152,7 @@ public class Lucene40TermVectorsReader extends TermVectorsReader {
 
   // Not private to avoid synthetic access$NNN methods
   void seekTvx(final int docNum) throws IOException {
-    tvx.seek(docNum * 16L + FORMAT_SIZE);
-  }
-
-  boolean canReadRawDocs() {
-    // we can always read raw docs, unless the term vectors
-    // didn't exist
-    return format != 0;
+    tvx.seek(docNum * 16L + HEADER_LENGTH_INDEX);
   }
 
   /** Retrieve the length (in bytes) of the tvd and tvf
@@ -210,16 +200,6 @@ public class Lucene40TermVectorsReader extends TermVectorsReader {
     }
   }
 
-  private int checkValidFormat(IndexInput in) throws CorruptIndexException, IOException
-  {
-    int format = in.readInt();
-    if (format < FORMAT_MINIMUM)
-      throw new IndexFormatTooOldException(in, format, FORMAT_MINIMUM, FORMAT_CURRENT);
-    if (format > FORMAT_CURRENT)
-      throw new IndexFormatTooNewException(in, format, FORMAT_MINIMUM, FORMAT_CURRENT);
-    return format;
-  }
-
   public void close() throws IOException {
     IOUtils.close(tvx, tvd, tvf);
   }
@@ -708,7 +688,7 @@ public class Lucene40TermVectorsReader extends TermVectorsReader {
       cloneTvf = (IndexInput) tvf.clone();
     }
     
-    return new Lucene40TermVectorsReader(fieldInfos, cloneTvx, cloneTvd, cloneTvf, size, numTotalDocs, format);
+    return new Lucene40TermVectorsReader(fieldInfos, cloneTvx, cloneTvd, cloneTvf, size, numTotalDocs);
   }
   
   public static void files(SegmentInfo info, Set<String> files) throws IOException {
diff --git a/lucene/core/src/java/org/apache/lucene/codecs/lucene40/Lucene40TermVectorsWriter.java b/lucene/core/src/java/org/apache/lucene/codecs/lucene40/Lucene40TermVectorsWriter.java
index 372db23..a61c321 100644
--- a/lucene/core/src/java/org/apache/lucene/codecs/lucene40/Lucene40TermVectorsWriter.java
+++ b/lucene/core/src/java/org/apache/lucene/codecs/lucene40/Lucene40TermVectorsWriter.java
@@ -35,9 +35,13 @@ import org.apache.lucene.store.IndexOutput;
 import org.apache.lucene.util.ArrayUtil;
 import org.apache.lucene.util.Bits;
 import org.apache.lucene.util.BytesRef;
+import org.apache.lucene.util.CodecUtil;
 import org.apache.lucene.util.IOUtils;
 import org.apache.lucene.util.StringHelper;
 
+import static org.apache.lucene.codecs.lucene40.Lucene40TermVectorsReader.*;
+
+
 // TODO: make a new 4.0 TV format that encodes better
 //   - use startOffset (not endOffset) as base for delta on
 //     next startOffset because today for syns or ngrams or
@@ -58,6 +62,8 @@ public final class Lucene40TermVectorsWriter extends TermVectorsWriter {
   private final Directory directory;
   private final String segment;
   private IndexOutput tvx = null, tvd = null, tvf = null;
+  
+ 
 
   public Lucene40TermVectorsWriter(Directory directory, String segment, IOContext context) throws IOException {
     this.directory = directory;
@@ -66,11 +72,14 @@ public final class Lucene40TermVectorsWriter extends TermVectorsWriter {
     try {
       // Open files for TermVector storage
       tvx = directory.createOutput(IndexFileNames.segmentFileName(segment, "", Lucene40TermVectorsReader.VECTORS_INDEX_EXTENSION), context);
-      tvx.writeInt(Lucene40TermVectorsReader.FORMAT_CURRENT);
+      CodecUtil.writeHeader(tvx, CODEC_NAME_INDEX, VERSION_CURRENT);
       tvd = directory.createOutput(IndexFileNames.segmentFileName(segment, "", Lucene40TermVectorsReader.VECTORS_DOCUMENTS_EXTENSION), context);
-      tvd.writeInt(Lucene40TermVectorsReader.FORMAT_CURRENT);
+      CodecUtil.writeHeader(tvd, CODEC_NAME_DOCS, VERSION_CURRENT);
       tvf = directory.createOutput(IndexFileNames.segmentFileName(segment, "", Lucene40TermVectorsReader.VECTORS_FIELDS_EXTENSION), context);
-      tvf.writeInt(Lucene40TermVectorsReader.FORMAT_CURRENT);
+      CodecUtil.writeHeader(tvf, CODEC_NAME_FIELDS, VERSION_CURRENT);
+      assert HEADER_LENGTH_INDEX == tvx.getFilePointer();
+      assert HEADER_LENGTH_DOCS == tvd.getFilePointer();
+      assert HEADER_LENGTH_FIELDS == tvf.getFilePointer();
       success = true;
     } finally {
       if (!success) {
@@ -252,10 +261,7 @@ public final class Lucene40TermVectorsWriter extends TermVectorsWriter {
         TermVectorsReader vectorsReader = matchingSegmentReader.getTermVectorsReader();
 
         if (vectorsReader != null && vectorsReader instanceof Lucene40TermVectorsReader) {
-          // If the TV* files are an older format then they cannot read raw docs:
-          if (((Lucene40TermVectorsReader)vectorsReader).canReadRawDocs()) {
             matchingVectorsReader = (Lucene40TermVectorsReader) vectorsReader;
-          }
         }
       }
       if (reader.liveDocs != null) {
@@ -356,7 +362,7 @@ public final class Lucene40TermVectorsWriter extends TermVectorsWriter {
   
   @Override
   public void finish(int numDocs) throws IOException {
-    if (4+((long) numDocs)*16 != tvx.getFilePointer())
+    if (HEADER_LENGTH_INDEX+((long) numDocs)*16 != tvx.getFilePointer())
       // This is most likely a bug in Sun JRE 1.6.0_04/_05;
       // we detect that the bug has struck, here, and
       // throw an exception to prevent the corruption from
diff --git a/lucene/core/src/java/org/apache/lucene/codecs/lucene40/values/Bytes.java b/lucene/core/src/java/org/apache/lucene/codecs/lucene40/values/Bytes.java
index 4ab1bd9..7fb3dd9 100644
--- a/lucene/core/src/java/org/apache/lucene/codecs/lucene40/values/Bytes.java
+++ b/lucene/core/src/java/org/apache/lucene/codecs/lucene40/values/Bytes.java
@@ -236,27 +236,34 @@ public final class Bytes {
     private IndexOutput datOut;
     protected BytesRef bytesRef = new BytesRef();
     private final Directory dir;
-    private final String codecName;
+    private final String codecNameIdx;
+    private final String codecNameDat;
     private final int version;
     private final IOContext context;
 
-    protected BytesWriterBase(Directory dir, String id, String codecName,
+    protected BytesWriterBase(Directory dir, String id, String codecNameIdx, String codecNameDat,
         int version, Counter bytesUsed, IOContext context, Type type) throws IOException {
       super(bytesUsed, type);
       this.id = id;
       this.dir = dir;
-      this.codecName = codecName;
+      this.codecNameIdx = codecNameIdx;
+      this.codecNameDat = codecNameDat;
       this.version = version;
       this.context = context;
+      assert codecNameDat != null || codecNameIdx != null: "both codec names are null";
+      assert (codecNameDat != null && !codecNameDat.equals(codecNameIdx)) 
+      || (codecNameIdx != null && !codecNameIdx.equals(codecNameDat)):
+        "index and data codec names must not be equal";
     }
     
     protected IndexOutput getOrCreateDataOut() throws IOException {
       if (datOut == null) {
         boolean success = false;
+        assert codecNameDat != null;
         try {
           datOut = dir.createOutput(IndexFileNames.segmentFileName(id, DV_SEGMENT_SUFFIX,
               DocValuesWriterBase.DATA_EXTENSION), context);
-          CodecUtil.writeHeader(datOut, codecName, version);
+          CodecUtil.writeHeader(datOut, codecNameDat, version);
           success = true;
         } finally {
           if (!success) {
@@ -279,9 +286,10 @@ public final class Bytes {
       boolean success = false;
       try {
         if (idxOut == null) {
+          assert codecNameIdx != null;
           idxOut = dir.createOutput(IndexFileNames.segmentFileName(id, DV_SEGMENT_SUFFIX,
               DocValuesWriterBase.INDEX_EXTENSION), context);
-          CodecUtil.writeHeader(idxOut, codecName, version);
+          CodecUtil.writeHeader(idxOut, codecNameIdx, version);
         }
         success = true;
       } finally {
@@ -308,8 +316,8 @@ public final class Bytes {
     protected final int version;
     protected final String id;
     protected final Type type;
-
-    protected BytesReaderBase(Directory dir, String id, String codecName,
+    
+    protected BytesReaderBase(Directory dir, String id, String codecNameIdx, String codecNameDat,
         int maxVersion, boolean doIndex, IOContext context, Type type) throws IOException {
       IndexInput dataIn = null;
       IndexInput indexIn = null;
@@ -317,11 +325,11 @@ public final class Bytes {
       try {
         dataIn = dir.openInput(IndexFileNames.segmentFileName(id, DV_SEGMENT_SUFFIX,
                                                               DocValuesWriterBase.DATA_EXTENSION), context);
-        version = CodecUtil.checkHeader(dataIn, codecName, maxVersion, maxVersion);
+        version = CodecUtil.checkHeader(dataIn, codecNameDat, maxVersion, maxVersion);
         if (doIndex) {
           indexIn = dir.openInput(IndexFileNames.segmentFileName(id, DV_SEGMENT_SUFFIX,
                                                                  DocValuesWriterBase.INDEX_EXTENSION), context);
-          final int version2 = CodecUtil.checkHeader(indexIn, codecName,
+          final int version2 = CodecUtil.checkHeader(indexIn, codecNameIdx,
                                                      maxVersion, maxVersion);
           assert version == version2;
         }
@@ -377,23 +385,23 @@ public final class Bytes {
     protected final boolean fasterButMoreRam;
     protected long maxBytes = 0;
     
-    protected DerefBytesWriterBase(Directory dir, String id, String codecName,
+    protected DerefBytesWriterBase(Directory dir, String id, String codecNameIdx, String codecNameDat,
         int codecVersion, Counter bytesUsed, IOContext context, Type type)
         throws IOException {
-      this(dir, id, codecName, codecVersion, new DirectTrackingAllocator(
+      this(dir, id, codecNameIdx, codecNameDat, codecVersion, new DirectTrackingAllocator(
           ByteBlockPool.BYTE_BLOCK_SIZE, bytesUsed), bytesUsed, context, false, type);
     }
 
-    protected DerefBytesWriterBase(Directory dir, String id, String codecName,
+    protected DerefBytesWriterBase(Directory dir, String id, String codecNameIdx, String codecNameDat,
                                    int codecVersion, Counter bytesUsed, IOContext context, boolean fasterButMoreRam, Type type)
         throws IOException {
-      this(dir, id, codecName, codecVersion, new DirectTrackingAllocator(
+      this(dir, id, codecNameIdx, codecNameDat, codecVersion, new DirectTrackingAllocator(
           ByteBlockPool.BYTE_BLOCK_SIZE, bytesUsed), bytesUsed, context, fasterButMoreRam,type);
     }
 
-    protected DerefBytesWriterBase(Directory dir, String id, String codecName, int codecVersion, Allocator allocator,
+    protected DerefBytesWriterBase(Directory dir, String id, String codecNameIdx, String codecNameDat, int codecVersion, Allocator allocator,
         Counter bytesUsed, IOContext context, boolean fasterButMoreRam, Type type) throws IOException {
-      super(dir, id, codecName, codecVersion, bytesUsed, context, type);
+      super(dir, id, codecNameIdx, codecNameDat, codecVersion, bytesUsed, context, type);
       hash = new BytesRefHash(new ByteBlockPool(allocator),
           BytesRefHash.DEFAULT_CAPACITY, new TrackingDirectBytesStartArray(
               BytesRefHash.DEFAULT_CAPACITY, bytesUsed));
diff --git a/lucene/core/src/java/org/apache/lucene/codecs/lucene40/values/FixedDerefBytesImpl.java b/lucene/core/src/java/org/apache/lucene/codecs/lucene40/values/FixedDerefBytesImpl.java
index 7c745b9..c7e8740 100644
--- a/lucene/core/src/java/org/apache/lucene/codecs/lucene40/values/FixedDerefBytesImpl.java
+++ b/lucene/core/src/java/org/apache/lucene/codecs/lucene40/values/FixedDerefBytesImpl.java
@@ -39,14 +39,16 @@ import org.apache.lucene.util.packed.PackedInts;
  */
 class FixedDerefBytesImpl {
 
-  static final String CODEC_NAME = "FixedDerefBytes";
+  static final String CODEC_NAME_IDX = "FixedDerefBytesIdx";
+  static final String CODEC_NAME_DAT = "FixedDerefBytesDat";
+
   static final int VERSION_START = 0;
   static final int VERSION_CURRENT = VERSION_START;
 
   public static class Writer extends DerefBytesWriterBase {
     public Writer(Directory dir, String id, Counter bytesUsed, IOContext context)
         throws IOException {
-      super(dir, id, CODEC_NAME, VERSION_CURRENT, bytesUsed, context, Type.BYTES_FIXED_DEREF);
+      super(dir, id, CODEC_NAME_IDX, CODEC_NAME_DAT, VERSION_CURRENT, bytesUsed, context, Type.BYTES_FIXED_DEREF);
     }
 
     @Override
@@ -71,7 +73,7 @@ class FixedDerefBytesImpl {
     private final int size;
     private final int numValuesStored;
     FixedDerefReader(Directory dir, String id, int maxDoc, IOContext context) throws IOException {
-      super(dir, id, CODEC_NAME, VERSION_START, true, context, Type.BYTES_FIXED_DEREF);
+      super(dir, id, CODEC_NAME_IDX, CODEC_NAME_DAT, VERSION_START, true, context, Type.BYTES_FIXED_DEREF);
       size = datIn.readInt();
       numValuesStored = idxIn.readInt();
     }
diff --git a/lucene/core/src/java/org/apache/lucene/codecs/lucene40/values/FixedSortedBytesImpl.java b/lucene/core/src/java/org/apache/lucene/codecs/lucene40/values/FixedSortedBytesImpl.java
index 2ab1700..278cb89 100644
--- a/lucene/core/src/java/org/apache/lucene/codecs/lucene40/values/FixedSortedBytesImpl.java
+++ b/lucene/core/src/java/org/apache/lucene/codecs/lucene40/values/FixedSortedBytesImpl.java
@@ -49,7 +49,8 @@ import org.apache.lucene.util.packed.PackedInts;
  */
 class FixedSortedBytesImpl {
 
-  static final String CODEC_NAME = "FixedSortedBytes";
+  static final String CODEC_NAME_IDX = "FixedSortedBytesIdx";
+  static final String CODEC_NAME_DAT = "FixedSortedBytesDat";
   static final int VERSION_START = 0;
   static final int VERSION_CURRENT = VERSION_START;
 
@@ -58,7 +59,7 @@ class FixedSortedBytesImpl {
 
     public Writer(Directory dir, String id, Comparator<BytesRef> comp,
         Counter bytesUsed, IOContext context, boolean fasterButMoreRam) throws IOException {
-      super(dir, id, CODEC_NAME, VERSION_CURRENT, bytesUsed, context, fasterButMoreRam, Type.BYTES_FIXED_SORTED);
+      super(dir, id, CODEC_NAME_IDX, CODEC_NAME_DAT, VERSION_CURRENT, bytesUsed, context, fasterButMoreRam, Type.BYTES_FIXED_SORTED);
       this.comp = comp;
     }
 
@@ -127,7 +128,7 @@ class FixedSortedBytesImpl {
 
     public Reader(Directory dir, String id, int maxDoc, IOContext context,
         Type type, Comparator<BytesRef> comparator) throws IOException {
-      super(dir, id, CODEC_NAME, VERSION_START, true, context, type);
+      super(dir, id, CODEC_NAME_IDX, CODEC_NAME_DAT, VERSION_START, true, context, type);
       size = datIn.readInt();
       valueCount = idxIn.readInt();
       this.comparator = comparator;
diff --git a/lucene/core/src/java/org/apache/lucene/codecs/lucene40/values/FixedStraightBytesImpl.java b/lucene/core/src/java/org/apache/lucene/codecs/lucene40/values/FixedStraightBytesImpl.java
index fd779ae..ced34f3 100644
--- a/lucene/core/src/java/org/apache/lucene/codecs/lucene40/values/FixedStraightBytesImpl.java
+++ b/lucene/core/src/java/org/apache/lucene/codecs/lucene40/values/FixedStraightBytesImpl.java
@@ -61,14 +61,14 @@ class FixedStraightBytesImpl {
     private final int byteBlockSize = BYTE_BLOCK_SIZE;
     private final ByteBlockPool pool;
 
-    protected FixedBytesWriterBase(Directory dir, String id, String codecName,
+    protected FixedBytesWriterBase(Directory dir, String id, String codecNameDat,
         int version, Counter bytesUsed, IOContext context) throws IOException {
-     this(dir, id, codecName, version, bytesUsed, context, Type.BYTES_FIXED_STRAIGHT);
+     this(dir, id, codecNameDat, version, bytesUsed, context, Type.BYTES_FIXED_STRAIGHT);
     }
     
-    protected FixedBytesWriterBase(Directory dir, String id, String codecName,
+    protected FixedBytesWriterBase(Directory dir, String id, String codecNameDat,
         int version, Counter bytesUsed, IOContext context, Type type) throws IOException {
-      super(dir, id, codecName, version, bytesUsed, context, type);
+      super(dir, id, null, codecNameDat, version, bytesUsed, context, type);
       pool = new ByteBlockPool(new DirectTrackingAllocator(bytesUsed));
       pool.nextBuffer();
     }
@@ -139,8 +139,8 @@ class FixedStraightBytesImpl {
       super(dir, id, CODEC_NAME, VERSION_CURRENT, bytesUsed, context);
     }
 
-    public Writer(Directory dir, String id, String codecName, int version, Counter bytesUsed, IOContext context) throws IOException {
-      super(dir, id, codecName, version, bytesUsed, context);
+    public Writer(Directory dir, String id, String codecNameDat, int version, Counter bytesUsed, IOContext context) throws IOException {
+      super(dir, id, codecNameDat, version, bytesUsed, context);
     }
 
 
@@ -268,8 +268,8 @@ class FixedStraightBytesImpl {
       this(dir, id, CODEC_NAME, VERSION_CURRENT, maxDoc, context, Type.BYTES_FIXED_STRAIGHT);
     }
 
-    protected FixedStraightReader(Directory dir, String id, String codec, int version, int maxDoc, IOContext context, Type type) throws IOException {
-      super(dir, id, codec, version, false, context, type);
+    protected FixedStraightReader(Directory dir, String id, String codecNameDat, int version, int maxDoc, IOContext context, Type type) throws IOException {
+      super(dir, id, null, codecNameDat, version, false, context, type);
       size = datIn.readInt();
       this.maxDoc = maxDoc;
     }
diff --git a/lucene/core/src/java/org/apache/lucene/codecs/lucene40/values/VarDerefBytesImpl.java b/lucene/core/src/java/org/apache/lucene/codecs/lucene40/values/VarDerefBytesImpl.java
index 43bff79..fa46bf6 100644
--- a/lucene/core/src/java/org/apache/lucene/codecs/lucene40/values/VarDerefBytesImpl.java
+++ b/lucene/core/src/java/org/apache/lucene/codecs/lucene40/values/VarDerefBytesImpl.java
@@ -41,7 +41,9 @@ import org.apache.lucene.util.packed.PackedInts;
  */
 class VarDerefBytesImpl {
 
-  static final String CODEC_NAME = "VarDerefBytes";
+  static final String CODEC_NAME_IDX = "VarDerefBytesIdx";
+  static final String CODEC_NAME_DAT = "VarDerefBytesDat";
+
   static final int VERSION_START = 0;
   static final int VERSION_CURRENT = VERSION_START;
 
@@ -57,7 +59,7 @@ class VarDerefBytesImpl {
   static class Writer extends DerefBytesWriterBase {
     public Writer(Directory dir, String id, Counter bytesUsed, IOContext context)
         throws IOException {
-      super(dir, id, CODEC_NAME, VERSION_CURRENT, bytesUsed, context, Type.BYTES_VAR_DEREF);
+      super(dir, id, CODEC_NAME_IDX, CODEC_NAME_DAT, VERSION_CURRENT, bytesUsed, context, Type.BYTES_VAR_DEREF);
       size = 0;
     }
     
@@ -93,7 +95,7 @@ class VarDerefBytesImpl {
   public static class VarDerefReader extends BytesReaderBase {
     private final long totalBytes;
     VarDerefReader(Directory dir, String id, int maxDoc, IOContext context) throws IOException {
-      super(dir, id, CODEC_NAME, VERSION_START, true, context, Type.BYTES_VAR_DEREF);
+      super(dir, id, CODEC_NAME_IDX, CODEC_NAME_DAT, VERSION_START, true, context, Type.BYTES_VAR_DEREF);
       totalBytes = idxIn.readLong();
     }
 
diff --git a/lucene/core/src/java/org/apache/lucene/codecs/lucene40/values/VarSortedBytesImpl.java b/lucene/core/src/java/org/apache/lucene/codecs/lucene40/values/VarSortedBytesImpl.java
index 9a8e87d..87c3f65 100644
--- a/lucene/core/src/java/org/apache/lucene/codecs/lucene40/values/VarSortedBytesImpl.java
+++ b/lucene/core/src/java/org/apache/lucene/codecs/lucene40/values/VarSortedBytesImpl.java
@@ -50,7 +50,9 @@ import org.apache.lucene.util.packed.PackedInts;
  */
 final class VarSortedBytesImpl {
 
-  static final String CODEC_NAME = "VarDerefBytes";
+  static final String CODEC_NAME_IDX = "VarDerefBytesIdx";
+  static final String CODEC_NAME_DAT = "VarDerefBytesDat";
+
   static final int VERSION_START = 0;
   static final int VERSION_CURRENT = VERSION_START;
 
@@ -59,7 +61,7 @@ final class VarSortedBytesImpl {
 
     public Writer(Directory dir, String id, Comparator<BytesRef> comp,
         Counter bytesUsed, IOContext context, boolean fasterButMoreRam) throws IOException {
-      super(dir, id, CODEC_NAME, VERSION_CURRENT, bytesUsed, context, fasterButMoreRam, Type.BYTES_VAR_SORTED);
+      super(dir, id, CODEC_NAME_IDX, CODEC_NAME_DAT, VERSION_CURRENT, bytesUsed, context, fasterButMoreRam, Type.BYTES_VAR_SORTED);
       this.comp = comp;
       size = 0;
     }
@@ -154,7 +156,7 @@ final class VarSortedBytesImpl {
     Reader(Directory dir, String id, int maxDoc,
         IOContext context, Type type, Comparator<BytesRef> comparator)
         throws IOException {
-      super(dir, id, CODEC_NAME, VERSION_START, true, context, type);
+      super(dir, id, CODEC_NAME_IDX, CODEC_NAME_DAT, VERSION_START, true, context, type);
       this.comparator = comparator;
     }
 
diff --git a/lucene/core/src/java/org/apache/lucene/codecs/lucene40/values/VarStraightBytesImpl.java b/lucene/core/src/java/org/apache/lucene/codecs/lucene40/values/VarStraightBytesImpl.java
index cfb9d78..ba18691 100644
--- a/lucene/core/src/java/org/apache/lucene/codecs/lucene40/values/VarStraightBytesImpl.java
+++ b/lucene/core/src/java/org/apache/lucene/codecs/lucene40/values/VarStraightBytesImpl.java
@@ -50,7 +50,9 @@ import org.apache.lucene.util.packed.PackedInts;
  */
 class VarStraightBytesImpl {
 
-  static final String CODEC_NAME = "VarStraightBytes";
+  static final String CODEC_NAME_IDX = "VarStraightBytesIdx";
+  static final String CODEC_NAME_DAT = "VarStraightBytesDat";
+
   static final int VERSION_START = 0;
   static final int VERSION_CURRENT = VERSION_START;
 
@@ -64,7 +66,7 @@ class VarStraightBytesImpl {
     private boolean merge = false;
     public Writer(Directory dir, String id, Counter bytesUsed, IOContext context)
         throws IOException {
-      super(dir, id, CODEC_NAME, VERSION_CURRENT, bytesUsed, context, Type.BYTES_VAR_STRAIGHT);
+      super(dir, id, CODEC_NAME_IDX, CODEC_NAME_DAT, VERSION_CURRENT, bytesUsed, context, Type.BYTES_VAR_STRAIGHT);
       pool = new ByteBlockPool(new DirectTrackingAllocator(bytesUsed));
       docToAddress = new long[1];
       pool.nextBuffer(); // init
@@ -236,7 +238,7 @@ class VarStraightBytesImpl {
     final int maxDoc;
 
     VarStraightReader(Directory dir, String id, int maxDoc, IOContext context) throws IOException {
-      super(dir, id, CODEC_NAME, VERSION_START, true, context, Type.BYTES_VAR_STRAIGHT);
+      super(dir, id, CODEC_NAME_IDX, CODEC_NAME_DAT, VERSION_START, true, context, Type.BYTES_VAR_STRAIGHT);
       this.maxDoc = maxDoc;
     }