diff --git a/core/commands/add.go b/core/commands/add.go
index a85ed4831..006c8c956 100644
--- a/core/commands/add.go
+++ b/core/commands/add.go
@@ -10,6 +10,7 @@ import (
 
 	"github.com/jbenet/go-ipfs/core"
 	"github.com/jbenet/go-ipfs/importer"
+	ft "github.com/jbenet/go-ipfs/importer/format"
 	dag "github.com/jbenet/go-ipfs/merkledag"
 	u "github.com/jbenet/go-ipfs/util"
 )
@@ -75,7 +76,7 @@ func AddPath(n *core.IpfsNode, fpath string, depth int) (*dag.Node, error) {
 }
 
 func addDir(n *core.IpfsNode, fpath string, depth int) (*dag.Node, error) {
-	tree := &dag.Node{Data: dag.FolderPBData()}
+	tree := &dag.Node{Data: ft.FolderPBData()}
 
 	files, err := ioutil.ReadDir(fpath)
 	if err != nil {
diff --git a/fuse/ipns/ipns_test.go b/fuse/ipns/ipns_test.go
index 760c530d0..c311c5225 100644
--- a/fuse/ipns/ipns_test.go
+++ b/fuse/ipns/ipns_test.go
@@ -63,6 +63,7 @@ func setupIpnsTest(t *testing.T, node *core.IpfsNode) (*core.IpfsNode, *fstest.M
 	return node, mnt
 }
 
+// Test writing a file and reading it back
 func TestIpnsBasicIO(t *testing.T) {
 	_, mnt := setupIpnsTest(t, nil)
 	defer mnt.Close()
@@ -80,6 +81,7 @@ func TestIpnsBasicIO(t *testing.T) {
 	}
 }
 
+// Test to make sure file changes persist over mounts of ipns
 func TestFilePersistence(t *testing.T) {
 	node, mnt := setupIpnsTest(t, nil)
 
@@ -104,6 +106,7 @@ func TestFilePersistence(t *testing.T) {
 	}
 }
 
+// Test to make sure the filesystem reports file sizes correctly
 func TestFileSizeReporting(t *testing.T) {
 	_, mnt := setupIpnsTest(t, nil)
 	defer mnt.Close()
@@ -120,3 +123,91 @@ func TestFileSizeReporting(t *testing.T) {
 		t.Fatal("Read incorrect size from stat!")
 	}
 }
+
+// Test to make sure you cant create multiple entries with the same name
+func TestDoubleEntryFailure(t *testing.T) {
+	_, mnt := setupIpnsTest(t, nil)
+	defer mnt.Close()
+
+	dname := mnt.Dir + "/local/thisisadir"
+	err := os.Mkdir(dname, 0777)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = os.Mkdir(dname, 0777)
+	if err == nil {
+		t.Fatal("Should have gotten error one creating new directory.")
+	}
+}
+
+func TestAppendFile(t *testing.T) {
+	_, mnt := setupIpnsTest(t, nil)
+	defer mnt.Close()
+
+	fname := mnt.Dir + "/local/file"
+	data := writeFile(t, 1300, fname)
+
+	fi, err := os.OpenFile(fname, os.O_RDWR|os.O_APPEND, 0666)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	nudata := randBytes(500)
+
+	n, err := fi.Write(nudata)
+	if err != nil {
+		t.Fatal(err)
+	}
+	err = fi.Close()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if n != len(nudata) {
+		t.Fatal("Failed to write enough bytes.")
+	}
+
+	data = append(data, nudata...)
+
+	rbuf, err := ioutil.ReadFile(fname)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(rbuf, data) {
+		t.Fatal("Data inconsistent!")
+	}
+}
+
+// Test writing a medium sized file one byte at a time
+func TestMultiWrite(t *testing.T) {
+	_, mnt := setupIpnsTest(t, nil)
+	defer mnt.Close()
+
+	fpath := mnt.Dir + "/local/file"
+	fi, err := os.Create(fpath)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	data := randBytes(1001)
+	for i := 0; i < len(data); i++ {
+		n, err := fi.Write(data[i : i+1])
+		if err != nil {
+			t.Fatal(err)
+		}
+		if n != 1 {
+			t.Fatal("Somehow wrote the wrong number of bytes! (n != 1)")
+		}
+	}
+	fi.Close()
+
+	rbuf, err := ioutil.ReadFile(fpath)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if !bytes.Equal(rbuf, data) {
+		t.Fatal("File on disk did not match bytes written")
+	}
+}
diff --git a/fuse/ipns/ipns_unix.go b/fuse/ipns/ipns_unix.go
index f172e4b84..7e6b1b33e 100644
--- a/fuse/ipns/ipns_unix.go
+++ b/fuse/ipns/ipns_unix.go
@@ -14,6 +14,7 @@ import (
 	"github.com/jbenet/go-ipfs/core"
 	ci "github.com/jbenet/go-ipfs/crypto"
 	imp "github.com/jbenet/go-ipfs/importer"
+	ft "github.com/jbenet/go-ipfs/importer/format"
 	mdag "github.com/jbenet/go-ipfs/merkledag"
 	u "github.com/jbenet/go-ipfs/util"
 )
@@ -77,7 +78,7 @@ func CreateRoot(n *core.IpfsNode, keys []ci.PrivKey, ipfsroot string) (*Root, er
 		pointsTo, err := n.Namesys.Resolve(name)
 		if err != nil {
 			log.Warning("Could not resolve value for local ipns entry, providing empty dir")
-			nd.Nd = &mdag.Node{Data: mdag.FolderPBData()}
+			nd.Nd = &mdag.Node{Data: ft.FolderPBData()}
 			root.LocalDirs[name] = nd
 			continue
 		}
@@ -199,14 +200,14 @@ type Node struct {
 	Ipfs   *core.IpfsNode
 	Nd     *mdag.Node
 	fd     *mdag.DagReader
-	cached *mdag.PBData
+	cached *ft.PBData
 
 	// For writing
 	writerBuf WriteAtBuf
 }
 
 func (s *Node) loadData() error {
-	s.cached = new(mdag.PBData)
+	s.cached = new(ft.PBData)
 	return proto.Unmarshal(s.Nd.Data, s.cached)
 }
 
@@ -216,10 +217,10 @@ func (s *Node) Attr() fuse.Attr {
 		s.loadData()
 	}
 	switch s.cached.GetType() {
-	case mdag.PBData_Directory:
+	case ft.PBData_Directory:
 		return fuse.Attr{Mode: os.ModeDir | 0555}
-	case mdag.PBData_File, mdag.PBData_Raw:
-		size, err := s.Nd.DataSize()
+	case ft.PBData_File, ft.PBData_Raw:
+		size, err := ft.DataSize(s.Nd.Data)
 		if err != nil {
 			log.Error("Error getting size of file: %s", err)
 			size = 0
@@ -414,7 +415,7 @@ func (n *Node) Fsync(req *fuse.FsyncRequest, intr fs.Intr) fuse.Error {
 
 func (n *Node) Mkdir(req *fuse.MkdirRequest, intr fs.Intr) (fs.Node, fuse.Error) {
 	log.Debug("Got mkdir request!")
-	dagnd := &mdag.Node{Data: mdag.FolderPBData()}
+	dagnd := &mdag.Node{Data: ft.FolderPBData()}
 	nnode := n.Nd.Copy()
 	nnode.AddNodeLink(req.Name, dagnd)
 
@@ -448,6 +449,12 @@ func (n *Node) Mkdir(req *fuse.MkdirRequest, intr fs.Intr) (fs.Node, fuse.Error)
 func (n *Node) Open(req *fuse.OpenRequest, resp *fuse.OpenResponse, intr fs.Intr) (fs.Handle, fuse.Error) {
 	//log.Debug("[%s] Received open request! flags = %s", n.name, req.Flags.String())
 	//TODO: check open flags and truncate if necessary
+	if req.Flags&fuse.OpenTruncate != 0 {
+		log.Warning("Need to truncate file!")
+	}
+	if req.Flags&fuse.OpenAppend != 0 {
+		log.Warning("Need to append to file!")
+	}
 	return n, nil
 }
 
@@ -460,7 +467,7 @@ func (n *Node) Create(req *fuse.CreateRequest, resp *fuse.CreateResponse, intr f
 	log.Debug("Got create request: %s", req.Name)
 
 	// New 'empty' file
-	nd := &mdag.Node{Data: mdag.FilePBData(nil, 0)}
+	nd := &mdag.Node{Data: ft.FilePBData(nil, 0)}
 	child := n.makeChild(req.Name, nd)
 
 	nnode := n.Nd.Copy()
diff --git a/fuse/readonly/readonly_unix.go b/fuse/readonly/readonly_unix.go
index 1bd45e8c2..e7550bee7 100644
--- a/fuse/readonly/readonly_unix.go
+++ b/fuse/readonly/readonly_unix.go
@@ -19,6 +19,7 @@ import (
 	"github.com/jbenet/go-ipfs/Godeps/_workspace/src/bazil.org/fuse"
 	"github.com/jbenet/go-ipfs/Godeps/_workspace/src/bazil.org/fuse/fs"
 	core "github.com/jbenet/go-ipfs/core"
+	ft "github.com/jbenet/go-ipfs/importer/format"
 	mdag "github.com/jbenet/go-ipfs/merkledag"
 	u "github.com/jbenet/go-ipfs/util"
 )
@@ -79,11 +80,11 @@ type Node struct {
 	Ipfs   *core.IpfsNode
 	Nd     *mdag.Node
 	fd     *mdag.DagReader
-	cached *mdag.PBData
+	cached *ft.PBData
 }
 
 func (s *Node) loadData() error {
-	s.cached = new(mdag.PBData)
+	s.cached = new(ft.PBData)
 	return proto.Unmarshal(s.Nd.Data, s.cached)
 }
 
@@ -94,9 +95,9 @@ func (s *Node) Attr() fuse.Attr {
 		s.loadData()
 	}
 	switch s.cached.GetType() {
-	case mdag.PBData_Directory:
+	case ft.PBData_Directory:
 		return fuse.Attr{Mode: os.ModeDir | 0555}
-	case mdag.PBData_File, mdag.PBData_Raw:
+	case ft.PBData_File, ft.PBData_Raw:
 		size, _ := s.Nd.Size()
 		return fuse.Attr{
 			Mode:   0444,
diff --git a/importer/dagwriter/dagwriter.go b/importer/dagwriter/dagwriter.go
new file mode 100644
index 000000000..2c2bbafb7
--- /dev/null
+++ b/importer/dagwriter/dagwriter.go
@@ -0,0 +1,80 @@
+package dagwriter
+
+import (
+	imp "github.com/jbenet/go-ipfs/importer"
+	ft "github.com/jbenet/go-ipfs/importer/format"
+	dag "github.com/jbenet/go-ipfs/merkledag"
+	"github.com/jbenet/go-ipfs/util"
+)
+
+var log = util.Logger("dagwriter")
+
+type DagWriter struct {
+	dagserv   *dag.DAGService
+	node      *dag.Node
+	totalSize int64
+	splChan   chan []byte
+	done      chan struct{}
+	splitter  imp.StreamSplitter
+	seterr    error
+}
+
+func NewDagWriter(ds *dag.DAGService, splitter imp.StreamSplitter) *DagWriter {
+	dw := new(DagWriter)
+	dw.dagserv = ds
+	dw.splChan = make(chan []byte, 8)
+	dw.splitter = splitter
+	dw.done = make(chan struct{})
+	go dw.startSplitter()
+	return dw
+}
+
+func (dw *DagWriter) startSplitter() {
+	blkchan := dw.splitter.Split(dw.splChan)
+	first := <-blkchan
+	root := new(dag.Node)
+	fileSize := uint64(0)
+	for blkData := range blkchan {
+		fileSize += uint64(len(blkData))
+		node := &dag.Node{Data: ft.WrapData(blkData)}
+		_, err := dw.dagserv.Add(node)
+		if err != nil {
+			dw.seterr = err
+			log.Critical("Got error adding created node to dagservice: %s", err)
+			return
+		}
+		err = root.AddNodeLinkClean("", node)
+		if err != nil {
+			dw.seterr = err
+			log.Critical("Got error adding created node to root node: %s", err)
+			return
+		}
+	}
+	root.Data = ft.FilePBData(first, fileSize)
+	_, err := dw.dagserv.Add(root)
+	if err != nil {
+		dw.seterr = err
+		log.Critical("Got error adding created node to dagservice: %s", err)
+		return
+	}
+	dw.node = root
+	dw.done <- struct{}{}
+}
+
+func (dw *DagWriter) Write(b []byte) (int, error) {
+	if dw.seterr != nil {
+		return 0, dw.seterr
+	}
+	dw.splChan <- b
+	return len(b), nil
+}
+
+func (dw *DagWriter) Close() error {
+	close(dw.splChan)
+	<-dw.done
+	return nil
+}
+
+func (dw *DagWriter) GetNode() *dag.Node {
+	return dw.node
+}
diff --git a/importer/dagwriter/dagwriter_test.go b/importer/dagwriter/dagwriter_test.go
new file mode 100644
index 000000000..114e363bf
--- /dev/null
+++ b/importer/dagwriter/dagwriter_test.go
@@ -0,0 +1,102 @@
+package dagwriter
+
+import (
+	"testing"
+
+	"io"
+
+	ds "github.com/jbenet/go-ipfs/Godeps/_workspace/src/github.com/jbenet/datastore.go"
+	bs "github.com/jbenet/go-ipfs/blockservice"
+	imp "github.com/jbenet/go-ipfs/importer"
+	mdag "github.com/jbenet/go-ipfs/merkledag"
+)
+
+type datasource struct {
+	i int
+}
+
+func (d *datasource) Read(b []byte) (int, error) {
+	for i, _ := range b {
+		b[i] = byte(d.i % 256)
+		d.i++
+	}
+	return len(b), nil
+}
+
+func (d *datasource) Matches(t *testing.T, r io.Reader, length int) bool {
+	b := make([]byte, 100)
+	i := 0
+	for {
+		n, err := r.Read(b)
+		if err != nil && err != io.EOF {
+			t.Fatal(err)
+		}
+		for _, v := range b[:n] {
+			if v != byte(i%256) {
+				t.Fatalf("Buffers differed at byte: %d (%d != %d)", i, v, (i % 256))
+			}
+			i++
+		}
+		if err == io.EOF {
+			break
+		}
+	}
+	if i != length {
+		t.Fatalf("Incorrect length. (%d != %d)", i, length)
+	}
+	return true
+}
+
+func TestDagWriter(t *testing.T) {
+	dstore := ds.NewMapDatastore()
+	bserv, err := bs.NewBlockService(dstore, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	dag := &mdag.DAGService{bserv}
+	dw := NewDagWriter(dag, &imp.SizeSplitter2{4096})
+
+	nbytes := int64(1024 * 1024 * 2)
+	n, err := io.CopyN(dw, &datasource{}, nbytes)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if n != nbytes {
+		t.Fatal("Copied incorrect amount of bytes!")
+	}
+
+	dw.Close()
+
+	node := dw.GetNode()
+	read, err := mdag.NewDagReader(node, dag)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	d := &datasource{}
+	if !d.Matches(t, read, int(nbytes)) {
+		t.Fatal("Failed to validate!")
+	}
+}
+
+func TestMassiveWrite(t *testing.T) {
+	t.SkipNow()
+	dstore := ds.NewNullDatastore()
+	bserv, err := bs.NewBlockService(dstore, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	dag := &mdag.DAGService{bserv}
+	dw := NewDagWriter(dag, &imp.SizeSplitter2{4096})
+
+	nbytes := int64(1024 * 1024 * 1024 * 16)
+	n, err := io.CopyN(dw, &datasource{}, nbytes)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if n != nbytes {
+		t.Fatal("Incorrect copy size.")
+	}
+	dw.Close()
+}
diff --git a/importer/format/Makefile b/importer/format/Makefile
new file mode 100644
index 000000000..87f182fe5
--- /dev/null
+++ b/importer/format/Makefile
@@ -0,0 +1,5 @@
+all: data.pb.go
+
+data.pb.go: data.proto
+	protoc --go_out=. data.proto
+
diff --git a/merkledag/data.pb.go b/importer/format/data.pb.go
similarity index 82%
rename from merkledag/data.pb.go
rename to importer/format/data.pb.go
index 3ed887533..9b8589d33 100644
--- a/merkledag/data.pb.go
+++ b/importer/format/data.pb.go
@@ -3,7 +3,7 @@
 // DO NOT EDIT!
 
 /*
-Package merkledag is a generated protocol buffer package.
+Package format is a generated protocol buffer package.
 
 It is generated from these files:
 	data.proto
@@ -11,7 +11,7 @@ It is generated from these files:
 It has these top-level messages:
 	PBData
 */
-package merkledag
+package format
 
 import proto "code.google.com/p/goprotobuf/proto"
 import math "math"
@@ -57,9 +57,10 @@ func (x *PBData_DataType) UnmarshalJSON(data []byte) error {
 }
 
 type PBData struct {
-	Type             *PBData_DataType `protobuf:"varint,1,req,enum=merkledag.PBData_DataType" json:"Type,omitempty"`
+	Type             *PBData_DataType `protobuf:"varint,1,req,enum=format.PBData_DataType" json:"Type,omitempty"`
 	Data             []byte           `protobuf:"bytes,2,opt" json:"Data,omitempty"`
 	Filesize         *uint64          `protobuf:"varint,3,opt,name=filesize" json:"filesize,omitempty"`
+	Blocksizes       []uint64         `protobuf:"varint,4,rep,name=blocksizes" json:"blocksizes,omitempty"`
 	XXX_unrecognized []byte           `json:"-"`
 }
 
@@ -88,6 +89,13 @@ func (m *PBData) GetFilesize() uint64 {
 	return 0
 }
 
-func init() {
-	proto.RegisterEnum("merkledag.PBData_DataType", PBData_DataType_name, PBData_DataType_value)
+func (m *PBData) GetBlocksizes() []uint64 {
+	if m != nil {
+		return m.Blocksizes
+	}
+	return nil
+}
+
+func init() {
+	proto.RegisterEnum("format.PBData_DataType", PBData_DataType_name, PBData_DataType_value)
 }
diff --git a/merkledag/data.proto b/importer/format/data.proto
similarity index 77%
rename from merkledag/data.proto
rename to importer/format/data.proto
index 043c9d1f9..9538c7c15 100644
--- a/merkledag/data.proto
+++ b/importer/format/data.proto
@@ -1,4 +1,4 @@
-package merkledag;
+package format;
 
 message PBData {
 	enum DataType {
@@ -10,4 +10,5 @@ message PBData {
 	required DataType Type = 1;
 	optional bytes Data = 2;
 	optional uint64 filesize = 3;
+	repeated uint64 blocksizes = 4;
 }
diff --git a/importer/format/format.go b/importer/format/format.go
new file mode 100644
index 000000000..f6dc14a39
--- /dev/null
+++ b/importer/format/format.go
@@ -0,0 +1,71 @@
+// Package format implements a data format for files in the ipfs filesystem
+// It is not the only format in ipfs, but it is the one that the filesystem assumes
+package format
+
+import (
+	"errors"
+
+	"code.google.com/p/goprotobuf/proto"
+)
+
+func FilePBData(data []byte, totalsize uint64) []byte {
+	pbfile := new(PBData)
+	typ := PBData_File
+	pbfile.Type = &typ
+	pbfile.Data = data
+	pbfile.Filesize = proto.Uint64(totalsize)
+
+	data, err := proto.Marshal(pbfile)
+	if err != nil {
+		//this really shouldnt happen, i promise
+		panic(err)
+	}
+	return data
+}
+
+func FolderPBData() []byte {
+	pbfile := new(PBData)
+	typ := PBData_Directory
+	pbfile.Type = &typ
+
+	data, err := proto.Marshal(pbfile)
+	if err != nil {
+		//this really shouldnt happen, i promise
+		panic(err)
+	}
+	return data
+}
+
+func WrapData(b []byte) []byte {
+	pbdata := new(PBData)
+	typ := PBData_Raw
+	pbdata.Data = b
+	pbdata.Type = &typ
+
+	out, err := proto.Marshal(pbdata)
+	if err != nil {
+		// This shouldnt happen. seriously.
+		panic(err)
+	}
+
+	return out
+}
+
+func DataSize(data []byte) (uint64, error) {
+	pbdata := new(PBData)
+	err := proto.Unmarshal(data, pbdata)
+	if err != nil {
+		return 0, err
+	}
+
+	switch pbdata.GetType() {
+	case PBData_Directory:
+		return 0, errors.New("Cant get data size of directory!")
+	case PBData_File:
+		return pbdata.GetFilesize(), nil
+	case PBData_Raw:
+		return uint64(len(pbdata.GetData())), nil
+	default:
+		return 0, errors.New("Unrecognized node data type!")
+	}
+}
diff --git a/importer/importer.go b/importer/importer.go
index ed4196e63..bbf6b5137 100644
--- a/importer/importer.go
+++ b/importer/importer.go
@@ -5,6 +5,7 @@ import (
 	"io"
 	"os"
 
+	ft "github.com/jbenet/go-ipfs/importer/format"
 	dag "github.com/jbenet/go-ipfs/merkledag"
 )
 
@@ -34,7 +35,7 @@ func NewDagFromReaderWithSplitter(r io.Reader, spl BlockSplitter) (*dag.Node, er
 	totalsize := uint64(len(first))
 	for blk := range blkChan {
 		totalsize += uint64(len(blk))
-		child := &dag.Node{Data: dag.WrapData(blk)}
+		child := &dag.Node{Data: ft.WrapData(blk)}
 		err := root.AddNodeLink(fmt.Sprintf("%d", i), child)
 		if err != nil {
 			return nil, err
@@ -42,7 +43,7 @@ func NewDagFromReaderWithSplitter(r io.Reader, spl BlockSplitter) (*dag.Node, er
 		i++
 	}
 
-	root.Data = dag.FilePBData(first, totalsize)
+	root.Data = ft.FilePBData(first, totalsize)
 	return root, nil
 }
 
diff --git a/importer/splitting.go b/importer/splitting.go
index 05eaec15a..65b672486 100644
--- a/importer/splitting.go
+++ b/importer/splitting.go
@@ -6,10 +6,16 @@ import (
 	u "github.com/jbenet/go-ipfs/util"
 )
 
+// OLD
 type BlockSplitter interface {
 	Split(io.Reader) chan []byte
 }
 
+// NEW
+type StreamSplitter interface {
+	Split(chan []byte) chan []byte
+}
+
 type SizeSplitter struct {
 	Size int
 }
@@ -39,3 +45,26 @@ func (ss *SizeSplitter) Split(r io.Reader) chan []byte {
 	}()
 	return out
 }
+
+type SizeSplitter2 struct {
+	Size int
+}
+
+func (ss *SizeSplitter2) Split(in chan []byte) chan []byte {
+	out := make(chan []byte)
+	go func() {
+		defer close(out)
+		var buf []byte
+		for b := range in {
+			buf = append(buf, b...)
+			for len(buf) > ss.Size {
+				out <- buf[:ss.Size]
+				buf = buf[ss.Size:]
+			}
+		}
+		if len(buf) > 0 {
+			out <- buf
+		}
+	}()
+	return out
+}
diff --git a/merkledag/Makefile b/merkledag/Makefile
index 2524ed3ba..711f34bda 100644
--- a/merkledag/Makefile
+++ b/merkledag/Makefile
@@ -1,11 +1,8 @@
 
-all: node.pb.go data.pb.go
+all: node.pb.go
 
 node.pb.go: node.proto
 	protoc --gogo_out=. --proto_path=../../../../:/usr/local/opt/protobuf/include:. $<
 
-data.pb.go: data.proto
-	protoc --go_out=. data.proto
-
 clean:
 	rm node.pb.go
diff --git a/merkledag/dagreader.go b/merkledag/dagreader.go
index 1e8a0c8b9..badc661fd 100644
--- a/merkledag/dagreader.go
+++ b/merkledag/dagreader.go
@@ -6,6 +6,7 @@ import (
 	"io"
 
 	proto "github.com/jbenet/go-ipfs/Godeps/_workspace/src/code.google.com/p/goprotobuf/proto"
+	ft "github.com/jbenet/go-ipfs/importer/format"
 	u "github.com/jbenet/go-ipfs/util"
 )
 
@@ -20,21 +21,21 @@ type DagReader struct {
 }
 
 func NewDagReader(n *Node, serv *DAGService) (io.Reader, error) {
-	pb := new(PBData)
+	pb := new(ft.PBData)
 	err := proto.Unmarshal(n.Data, pb)
 	if err != nil {
 		return nil, err
 	}
 	switch pb.GetType() {
-	case PBData_Directory:
+	case ft.PBData_Directory:
 		return nil, ErrIsDir
-	case PBData_File:
+	case ft.PBData_File:
 		return &DagReader{
 			node: n,
 			serv: serv,
 			buf:  bytes.NewBuffer(pb.GetData()),
 		}, nil
-	case PBData_Raw:
+	case ft.PBData_Raw:
 		return bytes.NewBuffer(pb.GetData()), nil
 	default:
 		panic("Unrecognized node type!")
@@ -54,7 +55,7 @@ func (dr *DagReader) precalcNextBuf() error {
 		}
 		nxt = nxtNode
 	}
-	pb := new(PBData)
+	pb := new(ft.PBData)
 	err := proto.Unmarshal(nxt.Data, pb)
 	if err != nil {
 		return err
@@ -62,13 +63,13 @@ func (dr *DagReader) precalcNextBuf() error {
 	dr.position++
 
 	switch pb.GetType() {
-	case PBData_Directory:
+	case ft.PBData_Directory:
 		panic("Why is there a directory under a file?")
-	case PBData_File:
+	case ft.PBData_File:
 		//TODO: this *should* work, needs testing first
 		//return NewDagReader(nxt, dr.serv)
 		panic("Not yet handling different layers of indirection!")
-	case PBData_Raw:
+	case ft.PBData_Raw:
 		dr.buf = bytes.NewBuffer(pb.GetData())
 		return nil
 	default:
diff --git a/merkledag/merkledag.go b/merkledag/merkledag.go
index 0db22d31c..675c8ccdd 100644
--- a/merkledag/merkledag.go
+++ b/merkledag/merkledag.go
@@ -1,11 +1,8 @@
 package merkledag
 
 import (
-	"errors"
 	"fmt"
 
-	proto "github.com/jbenet/go-ipfs/Godeps/_workspace/src/code.google.com/p/goprotobuf/proto"
-
 	mh "github.com/jbenet/go-ipfs/Godeps/_workspace/src/github.com/jbenet/go-multihash"
 	blocks "github.com/jbenet/go-ipfs/blocks"
 	bserv "github.com/jbenet/go-ipfs/blockservice"
@@ -37,6 +34,9 @@ type Link struct {
 	// cumulative size of target object
 	Size uint64
 
+	// cumulative size of data stored in object
+	DataSize uint64
+
 	// multihash of the target object
 	Hash mh.Multihash
 
@@ -46,14 +46,6 @@ type Link struct {
 
 // AddNodeLink adds a link to another node.
 func (n *Node) AddNodeLink(name string, that *Node) error {
-	// DEBUG CODE
-	for _, l := range n.Links {
-		if l.Name == name {
-			panic("Trying to add child that already exists!")
-		}
-	}
-	//
-
 	s, err := that.Size()
 	if err != nil {
 		return err
@@ -73,6 +65,27 @@ func (n *Node) AddNodeLink(name string, that *Node) error {
 	return nil
 }
 
+// AddNodeLink adds a link to another node. without keeping a reference to
+// the child node
+func (n *Node) AddNodeLinkClean(name string, that *Node) error {
+	s, err := that.Size()
+	if err != nil {
+		return err
+	}
+
+	h, err := that.Multihash()
+	if err != nil {
+		return err
+	}
+
+	n.Links = append(n.Links, &Link{
+		Name: name,
+		Size: s,
+		Hash: h,
+	})
+	return nil
+}
+
 func (n *Node) RemoveNodeLink(name string) error {
 	for i, l := range n.Links {
 		if l.Name == name {
@@ -83,6 +96,8 @@ func (n *Node) RemoveNodeLink(name string) error {
 	return u.ErrNotFound
 }
 
+// Copy returns a copy of the node.
+// NOTE: does not make copies of Node objects in the links.
 func (n *Node) Copy() *Node {
 	nnode := new(Node)
 	nnode.Data = make([]byte, len(n.Data))
@@ -108,25 +123,6 @@ func (n *Node) Size() (uint64, error) {
 	return s, nil
 }
 
-func (n *Node) DataSize() (uint64, error) {
-	pbdata := new(PBData)
-	err := proto.Unmarshal(n.Data, pbdata)
-	if err != nil {
-		return 0, err
-	}
-
-	switch pbdata.GetType() {
-	case PBData_Directory:
-		return 0, errors.New("Cant get data size of directory!")
-	case PBData_File:
-		return pbdata.GetFilesize(), nil
-	case PBData_Raw:
-		return uint64(len(pbdata.GetData())), nil
-	default:
-		return 0, errors.New("Unrecognized node data type!")
-	}
-}
-
 // Multihash hashes the encoded data of this node.
 func (n *Node) Multihash() (mh.Multihash, error) {
 	b, err := n.Encoded(false)
@@ -230,46 +226,3 @@ func (n *DAGService) Get(k u.Key) (*Node, error) {
 
 	return Decoded(b.Data)
 }
-
-func FilePBData(data []byte, totalsize uint64) []byte {
-	pbfile := new(PBData)
-	typ := PBData_File
-	pbfile.Type = &typ
-	pbfile.Data = data
-	pbfile.Filesize = proto.Uint64(totalsize)
-
-	data, err := proto.Marshal(pbfile)
-	if err != nil {
-		//this really shouldnt happen, i promise
-		panic(err)
-	}
-	return data
-}
-
-func FolderPBData() []byte {
-	pbfile := new(PBData)
-	typ := PBData_Directory
-	pbfile.Type = &typ
-
-	data, err := proto.Marshal(pbfile)
-	if err != nil {
-		//this really shouldnt happen, i promise
-		panic(err)
-	}
-	return data
-}
-
-func WrapData(b []byte) []byte {
-	pbdata := new(PBData)
-	typ := PBData_Raw
-	pbdata.Data = b
-	pbdata.Type = &typ
-
-	out, err := proto.Marshal(pbdata)
-	if err != nil {
-		// This shouldnt happen. seriously.
-		panic(err)
-	}
-
-	return out
-}
diff --git a/merkledag/merkledag_test.go b/merkledag/merkledag_test.go
index 7cd1649e2..2db166beb 100644
--- a/merkledag/merkledag_test.go
+++ b/merkledag/merkledag_test.go
@@ -2,8 +2,9 @@ package merkledag
 
 import (
 	"fmt"
-	u "github.com/jbenet/go-ipfs/util"
 	"testing"
+
+	u "github.com/jbenet/go-ipfs/util"
 )
 
 func TestNode(t *testing.T) {