diff --git a/unmaintained/diff_volume_servers/diff_volume_servers.go b/unmaintained/diff_volume_servers/diff_volume_servers.go
index e0f16e2d0..339d9c335 100644
--- a/unmaintained/diff_volume_servers/diff_volume_servers.go
+++ b/unmaintained/diff_volume_servers/diff_volume_servers.go
@@ -118,7 +118,7 @@ const (
 
 type needleState struct {
 	state uint8
-	size  uint32
+	size  types.Size
 }
 
 func getVolumeFiles(v uint32, addr string) (map[types.NeedleId]needleState, int64, error) {
@@ -154,8 +154,8 @@ func getVolumeFiles(v uint32, addr string) (map[types.NeedleId]needleState, int6
 
 	var maxOffset int64
 	files := map[types.NeedleId]needleState{}
-	err = idx.WalkIndexFile(idxFile, func(key types.NeedleId, offset types.Offset, size Size) error {
-		if offset.IsZero() || size == types.TombstoneFileSize {
+	err = idx.WalkIndexFile(idxFile, func(key types.NeedleId, offset types.Offset, size types.Size) error {
+		if offset.IsZero() || size < 0 || size == types.TombstoneFileSize {
 			files[key] = needleState{
 				state: stateDeleted,
 				size:  size,
diff --git a/unmaintained/fix_dat/fix_dat.go b/unmaintained/fix_dat/fix_dat.go
index d6110d870..70bce3bf9 100644
--- a/unmaintained/fix_dat/fix_dat.go
+++ b/unmaintained/fix_dat/fix_dat.go
@@ -98,7 +98,7 @@ func iterateEntries(datBackend backend.BackendStorageFile, idxFile *os.File, vis
 		// parse index file entry
 		key := util.BytesToUint64(bytes[0:8])
 		offsetFromIndex := util.BytesToUint32(bytes[8:12])
-		sizeFromIndex := util.BytesToUint32(bytes[12:16])
+		sizeFromIndex := types.BytesToSize(bytes[12:16])
 		count, _ = idxFile.ReadAt(bytes, readerOffset)
 		readerOffset += int64(count)
 
@@ -123,7 +123,7 @@ func iterateEntries(datBackend backend.BackendStorageFile, idxFile *os.File, vis
 			}
 		}()
 
-		if n.Size <= n.DataSize {
+		if n.Size <= types.Size(n.DataSize) {
 			continue
 		}
 		visitNeedle(n, offset)
diff --git a/unmaintained/see_dat/see_dat_gzip.go b/unmaintained/see_dat/see_dat_gzip.go
deleted file mode 100644
index cec073e3f..000000000
--- a/unmaintained/see_dat/see_dat_gzip.go
+++ /dev/null
@@ -1,83 +0,0 @@
-package main
-
-import (
-	"bytes"
-	"compress/gzip"
-	"crypto/md5"
-	"flag"
-	"io"
-	"io/ioutil"
-	"net/http"
-	"time"
-	"github.com/chrislusf/seaweedfs/weed/glog"
-	"github.com/chrislusf/seaweedfs/weed/storage"
-	"github.com/chrislusf/seaweedfs/weed/storage/needle"
-	"github.com/chrislusf/seaweedfs/weed/storage/super_block"
-	"github.com/chrislusf/seaweedfs/weed/util"
-)
-
-type VolumeFileScanner4SeeDat struct {
-	version needle.Version
-}
-
-func (scanner *VolumeFileScanner4SeeDat) VisitSuperBlock(superBlock super_block.SuperBlock) error {
-	scanner.version = superBlock.Version
-	return nil
-}
-
-func (scanner *VolumeFileScanner4SeeDat) ReadNeedleBody() bool {
-	return true
-}
-
-var (
-	files     = int64(0)
-	filebytes = int64(0)
-	diffbytes = int64(0)
-)
-
-func Compresssion(data []byte) float64 {
-	if len(data) <= 128 {
-		return 100.0
-	}
-	compressed, _ := util.GzipData(data[0:128])
-	return float64(len(compressed)*10) / 1280.0
-}
-
-func (scanner *VolumeFileScanner4SeeDat) VisitNeedle(n *needle.Needle, offset int64, needleHeader, needleBody []byte) error {
-	t := time.Unix(int64(n.AppendAtNs)/int64(time.Second), int64(n.AppendAtNs)%int64(time.Second))
-	glog.V(0).Info("----------------------------------------------------------------------------------")
-	glog.V(0).Infof("%d,%s%x offset %d size %d(%s) cookie %x appendedAt %v  hasmime[%t] mime[%s] (len: %d)",
-		*volumeId, n.Id, n.Cookie, offset, n.Size, util.BytesToHumanReadable(uint64(n.Size)), n.Cookie, t, n.HasMime(), string(n.Mime), len(n.Mime))
-	r, err := gzip.NewReader(bytes.NewReader(n.Data))
-	if err == nil {
-		buf := bytes.Buffer{}
-		h := md5.New()
-		c, _ := io.Copy(&buf, r)
-		d := buf.Bytes()
-		io.Copy(h, bytes.NewReader(d))
-		diff := (int64(n.DataSize) - int64(c))
-		diffbytes += diff
-		glog.V(0).Infof("was gzip! stored_size: %d orig_size: %d diff: %d(%d) mime:%s compression-of-128: %.2f md5: %x", n.DataSize, c, diff, diffbytes, http.DetectContentType(d), Compresssion(d), h.Sum(nil))
-	} else {
-		glog.V(0).Infof("no gzip!")
-	}
-	return nil
-}
-
-var (
-	_                = ioutil.ReadAll
-	volumePath       = flag.String("dir", "/tmp", "data directory to store files")
-	volumeCollection = flag.String("collection", "", "the volume collection name")
-	volumeId         = flag.Int("volumeId", -1, "a volume id. The volume should already exist in the dir. The volume index file should not exist.")
-)
-
-func main() {
-	flag.Parse()
-	vid := needle.VolumeId(*volumeId)
-	glog.V(0).Info("Starting")
-	scanner := &VolumeFileScanner4SeeDat{}
-	err := storage.ScanVolumeFile(*volumePath, *volumeCollection, vid, storage.NeedleMapInMemory, scanner)
-	if err != nil {
-		glog.Fatalf("Reading Volume File [ERROR] %s\n", err)
-	}
-}
diff --git a/unmaintained/see_idx/see_idx.go b/unmaintained/see_idx/see_idx.go
index 31e4bae05..22c659351 100644
--- a/unmaintained/see_idx/see_idx.go
+++ b/unmaintained/see_idx/see_idx.go
@@ -36,7 +36,7 @@ func main() {
 	}
 	defer indexFile.Close()
 
-	idx.WalkIndexFile(indexFile, func(key types.NeedleId, offset types.Offset, size Size) error {
+	idx.WalkIndexFile(indexFile, func(key types.NeedleId, offset types.Offset, size types.Size) error {
 		fmt.Printf("key:%v offset:%v size:%v(%v)\n", key, offset, size, util.BytesToHumanReadable(uint64(size)))
 		return nil
 	})