diff --git a/storagedriver/azure/azure.go b/storagedriver/azure/azure.go
index ba716841..489a6348 100644
--- a/storagedriver/azure/azure.go
+++ b/storagedriver/azure/azure.go
@@ -103,7 +103,7 @@ func (d *Driver) PutContent(path string, contents []byte) error {
 
 // ReadStream retrieves an io.ReadCloser for the content stored at "path" with a
 // given byte offset.
-func (d *Driver) ReadStream(path string, offset uint64) (io.ReadCloser, error) {
+func (d *Driver) ReadStream(path string, offset int64) (io.ReadCloser, error) {
 	if ok, err := d.client.BlobExists(d.container, path); err != nil {
 		return nil, err
 	} else if !ok {
@@ -115,7 +115,7 @@ func (d *Driver) ReadStream(path string, offset uint64) (io.ReadCloser, error) {
 		return nil, err
 	}
 
-	if offset >= size {
+	if offset >= int64(size) {
 		return nil, storagedriver.InvalidOffsetError{Path: path, Offset: offset}
 	}
 
@@ -129,10 +129,10 @@ func (d *Driver) ReadStream(path string, offset uint64) (io.ReadCloser, error) {
 
 // WriteStream stores the contents of the provided io.ReadCloser at a location
 // designated by the given path.
-func (d *Driver) WriteStream(path string, offset, size uint64, reader io.ReadCloser) error {
+func (d *Driver) WriteStream(path string, offset, size int64, reader io.ReadCloser) error {
 	var (
 		lastBlockNum    int
-		resumableOffset uint64
+		resumableOffset int64
 		blocks          []azure.Block
 	)
 
@@ -153,12 +153,12 @@ func (d *Driver) WriteStream(path string, offset, size uint64, reader io.ReadClo
 				return fmt.Errorf("Cannot parse block name as number '%s': %s", lastBlock.Name, err.Error())
 			}
 
-			var totalSize uint64
+			var totalSize int64
 			for _, v := range parts.CommittedBlocks {
 				blocks = append(blocks, azure.Block{
 					Id:     v.Name,
 					Status: azure.BlockStatusCommitted})
-				totalSize += uint64(v.Size)
+				totalSize += int64(v.Size)
 			}
 
 			// NOTE: Azure driver currently supports only append mode (resumable
diff --git a/storagedriver/filesystem/driver.go b/storagedriver/filesystem/driver.go
index a4b2e688..3fbfcdf6 100644
--- a/storagedriver/filesystem/driver.go
+++ b/storagedriver/filesystem/driver.go
@@ -80,7 +80,7 @@ func (d *Driver) PutContent(subPath string, contents []byte) error {
 
 // ReadStream retrieves an io.ReadCloser for the content stored at "path" with a
 // given byte offset.
-func (d *Driver) ReadStream(path string, offset uint64) (io.ReadCloser, error) {
+func (d *Driver) ReadStream(path string, offset int64) (io.ReadCloser, error) {
 	file, err := os.OpenFile(d.subPath(path), os.O_RDONLY, 0644)
 	if err != nil {
 		return nil, storagedriver.PathNotFoundError{Path: path}
@@ -100,7 +100,7 @@ func (d *Driver) ReadStream(path string, offset uint64) (io.ReadCloser, error) {
 
 // WriteStream stores the contents of the provided io.ReadCloser at a location
 // designated by the given path.
-func (d *Driver) WriteStream(subPath string, offset, size uint64, reader io.ReadCloser) error {
+func (d *Driver) WriteStream(subPath string, offset, size int64, reader io.ReadCloser) error {
 	defer reader.Close()
 
 	resumableOffset, err := d.CurrentSize(subPath)
@@ -108,7 +108,7 @@ func (d *Driver) WriteStream(subPath string, offset, size uint64, reader io.Read
 		return err
 	}
 
-	if offset > resumableOffset {
+	if offset > int64(resumableOffset) {
 		return storagedriver.InvalidOffsetError{Path: subPath, Offset: offset}
 	}
 
@@ -131,13 +131,15 @@ func (d *Driver) WriteStream(subPath string, offset, size uint64, reader io.Read
 	}
 	defer file.Close()
 
+	// TODO(sday): Use Seek + Copy here.
+
 	buf := make([]byte, 32*1024)
 	for {
 		bytesRead, er := reader.Read(buf)
 		if bytesRead > 0 {
 			bytesWritten, ew := file.WriteAt(buf[0:bytesRead], int64(offset))
 			if bytesWritten > 0 {
-				offset += uint64(bytesWritten)
+				offset += int64(bytesWritten)
 			}
 			if ew != nil {
 				err = ew
diff --git a/storagedriver/inmemory/driver.go b/storagedriver/inmemory/driver.go
index 98b068e9..3231b017 100644
--- a/storagedriver/inmemory/driver.go
+++ b/storagedriver/inmemory/driver.go
@@ -61,7 +61,7 @@ func (d *Driver) PutContent(path string, contents []byte) error {
 
 // ReadStream retrieves an io.ReadCloser for the content stored at "path" with a
 // given byte offset.
-func (d *Driver) ReadStream(path string, offset uint64) (io.ReadCloser, error) {
+func (d *Driver) ReadStream(path string, offset int64) (io.ReadCloser, error) {
 	d.mutex.RLock()
 	defer d.mutex.RUnlock()
 	contents, err := d.GetContent(path)
@@ -79,7 +79,7 @@ func (d *Driver) ReadStream(path string, offset uint64) (io.ReadCloser, error) {
 
 // WriteStream stores the contents of the provided io.ReadCloser at a location
 // designated by the given path.
-func (d *Driver) WriteStream(path string, offset, size uint64, reader io.ReadCloser) error {
+func (d *Driver) WriteStream(path string, offset, size int64, reader io.ReadCloser) error {
 	defer reader.Close()
 	d.mutex.RLock()
 	defer d.mutex.RUnlock()
@@ -89,7 +89,7 @@ func (d *Driver) WriteStream(path string, offset, size uint64, reader io.ReadClo
 		return err
 	}
 
-	if offset > resumableOffset {
+	if offset > int64(resumableOffset) {
 		return storagedriver.InvalidOffsetError{Path: path, Offset: offset}
 	}
 
diff --git a/storagedriver/ipc/client.go b/storagedriver/ipc/client.go
index c77797eb..7e52a084 100644
--- a/storagedriver/ipc/client.go
+++ b/storagedriver/ipc/client.go
@@ -234,7 +234,7 @@ func (driver *StorageDriverClient) PutContent(path string, contents []byte) erro
 
 // ReadStream retrieves an io.ReadCloser for the content stored at "path" with a
 // given byte offset.
-func (driver *StorageDriverClient) ReadStream(path string, offset uint64) (io.ReadCloser, error) {
+func (driver *StorageDriverClient) ReadStream(path string, offset int64) (io.ReadCloser, error) {
 	if err := driver.exited(); err != nil {
 		return nil, err
 	}
@@ -261,7 +261,7 @@ func (driver *StorageDriverClient) ReadStream(path string, offset uint64) (io.Re
 
 // WriteStream stores the contents of the provided io.ReadCloser at a location
 // designated by the given path.
-func (driver *StorageDriverClient) WriteStream(path string, offset, size uint64, reader io.ReadCloser) error {
+func (driver *StorageDriverClient) WriteStream(path string, offset, size int64, reader io.ReadCloser) error {
 	if err := driver.exited(); err != nil {
 		return err
 	}
diff --git a/storagedriver/ipc/server.go b/storagedriver/ipc/server.go
index 7d1876ca..1c0084f9 100644
--- a/storagedriver/ipc/server.go
+++ b/storagedriver/ipc/server.go
@@ -100,7 +100,7 @@ func handleRequest(driver storagedriver.StorageDriver, request Request) {
 	case "ReadStream":
 		path, _ := request.Parameters["Path"].(string)
 		// Depending on serialization method, Offset may be convereted to any int/uint type
-		offset := reflect.ValueOf(request.Parameters["Offset"]).Convert(reflect.TypeOf(uint64(0))).Uint()
+		offset := reflect.ValueOf(request.Parameters["Offset"]).Convert(reflect.TypeOf(int64(0))).Int()
 		reader, err := driver.ReadStream(path, offset)
 		var response ReadStreamResponse
 		if err != nil {
@@ -115,9 +115,9 @@ func handleRequest(driver storagedriver.StorageDriver, request Request) {
 	case "WriteStream":
 		path, _ := request.Parameters["Path"].(string)
 		// Depending on serialization method, Offset may be convereted to any int/uint type
-		offset := reflect.ValueOf(request.Parameters["Offset"]).Convert(reflect.TypeOf(uint64(0))).Uint()
+		offset := reflect.ValueOf(request.Parameters["Offset"]).Convert(reflect.TypeOf(int64(0))).Int()
 		// Depending on serialization method, Size may be convereted to any int/uint type
-		size := reflect.ValueOf(request.Parameters["Size"]).Convert(reflect.TypeOf(uint64(0))).Uint()
+		size := reflect.ValueOf(request.Parameters["Size"]).Convert(reflect.TypeOf(int64(0))).Int()
 		reader, _ := request.Parameters["Reader"].(io.ReadCloser)
 		err := driver.WriteStream(path, offset, size, reader)
 		response := WriteStreamResponse{
diff --git a/storagedriver/s3/s3.go b/storagedriver/s3/s3.go
index def03e3e..3d5cd511 100644
--- a/storagedriver/s3/s3.go
+++ b/storagedriver/s3/s3.go
@@ -17,7 +17,7 @@ const driverName = "s3"
 
 // minChunkSize defines the minimum multipart upload chunk size
 // S3 API requires multipart upload chunks to be at least 5MB
-const minChunkSize = uint64(5 * 1024 * 1024)
+const minChunkSize = 5 * 1024 * 1024
 
 // listPartsMax is the largest amount of parts you can request from S3
 const listPartsMax = 1000
@@ -120,9 +120,9 @@ func (d *Driver) PutContent(path string, contents []byte) error {
 
 // ReadStream retrieves an io.ReadCloser for the content stored at "path" with a
 // given byte offset.
-func (d *Driver) ReadStream(path string, offset uint64) (io.ReadCloser, error) {
+func (d *Driver) ReadStream(path string, offset int64) (io.ReadCloser, error) {
 	headers := make(http.Header)
-	headers.Add("Range", "bytes="+strconv.FormatUint(offset, 10)+"-")
+	headers.Add("Range", "bytes="+strconv.FormatInt(offset, 10)+"-")
 
 	resp, err := d.Bucket.GetResponseWithHeaders(path, headers)
 	if err != nil {
@@ -133,22 +133,22 @@ func (d *Driver) ReadStream(path string, offset uint64) (io.ReadCloser, error) {
 
 // WriteStream stores the contents of the provided io.ReadCloser at a location
 // designated by the given path.
-func (d *Driver) WriteStream(path string, offset, size uint64, reader io.ReadCloser) error {
+func (d *Driver) WriteStream(path string, offset, size int64, reader io.ReadCloser) error {
 	defer reader.Close()
 
-	chunkSize := minChunkSize
+	chunkSize := int64(minChunkSize)
 	for size/chunkSize >= listPartsMax {
 		chunkSize *= 2
 	}
 
 	partNumber := 1
-	totalRead := uint64(0)
+	var totalRead int64
 	multi, parts, err := d.getAllParts(path)
 	if err != nil {
 		return err
 	}
 
-	if (offset) > uint64(len(parts))*chunkSize || (offset < size && offset%chunkSize != 0) {
+	if (offset) > int64(len(parts))*chunkSize || (offset < size && offset%chunkSize != 0) {
 		return storagedriver.InvalidOffsetError{Path: path, Offset: offset}
 	}
 
@@ -161,11 +161,11 @@ func (d *Driver) WriteStream(path string, offset, size uint64, reader io.ReadClo
 	buf := make([]byte, chunkSize)
 	for {
 		bytesRead, err := io.ReadFull(reader, buf)
-		totalRead += uint64(bytesRead)
+		totalRead += int64(bytesRead)
 
 		if err != nil && err != io.ErrUnexpectedEOF && err != io.EOF {
 			return err
-		} else if (uint64(bytesRead) < chunkSize) && totalRead != size {
+		} else if (int64(bytesRead) < chunkSize) && totalRead != size {
 			break
 		} else {
 			part, err := multi.PutPart(int(partNumber), bytes.NewReader(buf[0:bytesRead]))
diff --git a/storagedriver/storagedriver.go b/storagedriver/storagedriver.go
index 1b6c5c00..d257e4b2 100644
--- a/storagedriver/storagedriver.go
+++ b/storagedriver/storagedriver.go
@@ -44,7 +44,7 @@ type StorageDriver interface {
 	// ReadStream retrieves an io.ReadCloser for the content stored at "path"
 	// with a given byte offset.
 	// May be used to resume reading a stream by providing a nonzero offset.
-	ReadStream(path string, offset uint64) (io.ReadCloser, error)
+	ReadStream(path string, offset int64) (io.ReadCloser, error)
 
 	// WriteStream stores the contents of the provided io.ReadCloser at a
 	// location designated by the given path.
@@ -52,7 +52,7 @@ type StorageDriver interface {
 	// "size" bytes.
 	// May be used to resume writing a stream by providing a nonzero offset.
 	// The offset must be no larger than the CurrentSize for this path.
-	WriteStream(path string, offset, size uint64, readCloser io.ReadCloser) error
+	WriteStream(path string, offset, size int64, readCloser io.ReadCloser) error
 
 	// CurrentSize retrieves the curernt size in bytes of the object at the
 	// given path.
@@ -86,7 +86,7 @@ func (err PathNotFoundError) Error() string {
 // invalid offset.
 type InvalidOffsetError struct {
 	Path   string
-	Offset uint64
+	Offset int64
 }
 
 func (err InvalidOffsetError) Error() string {
diff --git a/storagedriver/testsuites/testsuites.go b/storagedriver/testsuites/testsuites.go
index 61756667..c2604f4f 100644
--- a/storagedriver/testsuites/testsuites.go
+++ b/storagedriver/testsuites/testsuites.go
@@ -173,7 +173,7 @@ func (suite *DriverSuite) TestContinueStreamAppend(c *check.C) {
 	filename := randomString(32)
 	defer suite.StorageDriver.Delete(filename)
 
-	chunkSize := uint64(10 * 1024 * 1024)
+	chunkSize := int64(10 * 1024 * 1024)
 
 	contentsChunk1 := []byte(randomString(chunkSize))
 	contentsChunk2 := []byte(randomString(chunkSize))
@@ -186,19 +186,19 @@ func (suite *DriverSuite) TestContinueStreamAppend(c *check.C) {
 
 	offset, err := suite.StorageDriver.CurrentSize(filename)
 	c.Assert(err, check.IsNil)
-	if offset > chunkSize {
+	if int64(offset) > chunkSize {
 		c.Fatalf("Offset too large, %d > %d", offset, chunkSize)
 	}
-	err = suite.StorageDriver.WriteStream(filename, offset, 3*chunkSize, ioutil.NopCloser(bytes.NewReader(fullContents[offset:2*chunkSize])))
+	err = suite.StorageDriver.WriteStream(filename, int64(offset), 3*chunkSize, ioutil.NopCloser(bytes.NewReader(fullContents[offset:2*chunkSize])))
 	c.Assert(err, check.IsNil)
 
 	offset, err = suite.StorageDriver.CurrentSize(filename)
 	c.Assert(err, check.IsNil)
-	if offset > 2*chunkSize {
+	if int64(offset) > 2*chunkSize {
 		c.Fatalf("Offset too large, %d > %d", offset, 2*chunkSize)
 	}
 
-	err = suite.StorageDriver.WriteStream(filename, offset, 3*chunkSize, ioutil.NopCloser(bytes.NewReader(fullContents[offset:])))
+	err = suite.StorageDriver.WriteStream(filename, int64(offset), 3*chunkSize, ioutil.NopCloser(bytes.NewReader(fullContents[offset:])))
 	c.Assert(err, check.IsNil)
 
 	received, err := suite.StorageDriver.GetContent(filename)
@@ -212,7 +212,7 @@ func (suite *DriverSuite) TestReadStreamWithOffset(c *check.C) {
 	filename := randomString(32)
 	defer suite.StorageDriver.Delete(filename)
 
-	chunkSize := uint64(32)
+	chunkSize := int64(32)
 
 	contentsChunk1 := []byte(randomString(chunkSize))
 	contentsChunk2 := []byte(randomString(chunkSize))
@@ -260,13 +260,13 @@ func (suite *DriverSuite) TestReadNonexistentStream(c *check.C) {
 
 // TestList checks the returned list of keys after populating a directory tree.
 func (suite *DriverSuite) TestList(c *check.C) {
-	rootDirectory := "/" + randomString(uint64(8+rand.Intn(8)))
+	rootDirectory := "/" + randomString(int64(8+rand.Intn(8)))
 	defer suite.StorageDriver.Delete(rootDirectory)
 
-	parentDirectory := rootDirectory + "/" + randomString(uint64(8+rand.Intn(8)))
+	parentDirectory := rootDirectory + "/" + randomString(int64(8+rand.Intn(8)))
 	childFiles := make([]string, 50)
 	for i := 0; i < len(childFiles); i++ {
-		childFile := parentDirectory + "/" + randomString(uint64(8+rand.Intn(8)))
+		childFile := parentDirectory + "/" + randomString(int64(8+rand.Intn(8)))
 		childFiles[i] = childFile
 		err := suite.StorageDriver.PutContent(childFile, []byte(randomString(32)))
 		c.Assert(err, check.IsNil)
@@ -388,7 +388,7 @@ func (suite *DriverSuite) TestConcurrentFileStreams(c *check.C) {
 
 	doneChan := make(chan struct{})
 
-	testStream := func(size int) {
+	testStream := func(size int64) {
 		suite.testFileStreams(c, size)
 		doneChan <- struct{}{}
 	}
@@ -406,7 +406,7 @@ func (suite *DriverSuite) TestConcurrentFileStreams(c *check.C) {
 
 }
 
-func (suite *DriverSuite) testFileStreams(c *check.C, size int) {
+func (suite *DriverSuite) testFileStreams(c *check.C, size int64) {
 	tf, err := ioutil.TempFile("", "tf")
 	c.Assert(err, check.IsNil)
 	defer os.Remove(tf.Name())
@@ -414,7 +414,7 @@ func (suite *DriverSuite) testFileStreams(c *check.C, size int) {
 	tfName := path.Base(tf.Name())
 	defer suite.StorageDriver.Delete(tfName)
 
-	contents := []byte(randomString(uint64(size)))
+	contents := []byte(randomString(size))
 
 	_, err = tf.Write(contents)
 	c.Assert(err, check.IsNil)
@@ -422,7 +422,7 @@ func (suite *DriverSuite) testFileStreams(c *check.C, size int) {
 	tf.Sync()
 	tf.Seek(0, os.SEEK_SET)
 
-	err = suite.StorageDriver.WriteStream(tfName, 0, uint64(size), tf)
+	err = suite.StorageDriver.WriteStream(tfName, 0, size, tf)
 	c.Assert(err, check.IsNil)
 
 	reader, err := suite.StorageDriver.ReadStream(tfName, 0)
@@ -450,7 +450,7 @@ func (suite *DriverSuite) writeReadCompare(c *check.C, filename string, contents
 func (suite *DriverSuite) writeReadCompareStreams(c *check.C, filename string, contents []byte) {
 	defer suite.StorageDriver.Delete(filename)
 
-	err := suite.StorageDriver.WriteStream(filename, 0, uint64(len(contents)), ioutil.NopCloser(bytes.NewReader(contents)))
+	err := suite.StorageDriver.WriteStream(filename, 0, int64(len(contents)), ioutil.NopCloser(bytes.NewReader(contents)))
 	c.Assert(err, check.IsNil)
 
 	reader, err := suite.StorageDriver.ReadStream(filename, 0)
@@ -465,7 +465,7 @@ func (suite *DriverSuite) writeReadCompareStreams(c *check.C, filename string, c
 
 var pathChars = []byte("abcdefghijklmnopqrstuvwxyz")
 
-func randomString(length uint64) string {
+func randomString(length int64) string {
 	b := make([]byte, length)
 	for i := range b {
 		b[i] = pathChars[rand.Intn(len(pathChars))]