diff --git a/fs_test.go b/fs_test.go
index 301fc13..99ab330 100644
--- a/fs_test.go
+++ b/fs_test.go
@@ -16,6 +16,7 @@
 
 import (
 	"bytes"
+	"fmt"
 	"io"
 	"io/ioutil"
 	"os"
@@ -288,6 +289,20 @@
 		}
 		f.WriteString("Testfile 2 content")
 		f.Close()
+
+		f, err = fs.Create(filepath.Join(testSubDir, "testfile3"))
+		if err != nil {
+			t.Fatal(err)
+		}
+		f.WriteString("Testfile 3 content")
+		f.Close()
+
+		f, err = fs.Create(filepath.Join(testSubDir, "testfile4"))
+		if err != nil {
+			t.Fatal(err)
+		}
+		f.WriteString("Testfile 4 content")
+		f.Close()
 	}
 }
 
@@ -315,7 +330,81 @@
 	}
 }
 
+func TestReaddirSimple(t *testing.T) {
+	for _, fs := range Fss {
+		root, err := fs.Open(testDir)
+		if err != nil {
+			t.Fatal(err)
+		}
+		rootInfo, err := root.Readdir(1)
+		if err != nil {
+			t.Log(myFileInfo(rootInfo))
+			t.Error(err)
+		}
+		rootInfo, err = root.Readdir(5)
+		if err != io.EOF {
+			t.Log(myFileInfo(rootInfo))
+			t.Error(err)
+		}
+
+		sub, err := fs.Open(testSubDir)
+		if err != nil {
+			t.Fatal(err)
+		}
+		subInfo, err := sub.Readdir(5)
+		if err != nil {
+			t.Log(myFileInfo(subInfo))
+			t.Error(err)
+		}
+	}
+}
+
 func TestReaddir(t *testing.T) {
+	for num := 0; num < 6; num++ {
+		outputs := make([]string, len(Fss))
+		for i, fs := range Fss {
+			root, err := fs.Open(testSubDir)
+			if err != nil {
+				t.Fatal(err)
+			}
+			for j := 0; j < 6; j++ {
+				info, err := root.Readdir(num)
+				outputs[i] += fmt.Sprintf("%v  Error: %v\n", myFileInfo(info), err)
+			}
+		}
+
+		fail := false
+		for i, o := range outputs {
+			if i == 0 {
+				continue
+			}
+			if o != outputs[i-1] {
+				fail = true
+				break
+			}
+		}
+		if fail {
+			t.Log("Readdir outputs not equal for Readdir(", num, ")")
+			for i, o := range outputs {
+				t.Log(Fss[i].Name())
+				t.Log(o)
+			}
+			t.Fail()
+		}
+	}
+}
+
+type myFileInfo []os.FileInfo
+
+func (m myFileInfo) String() string {
+	out := "Fileinfos:\n"
+	for _, e := range m {
+		out += "  " + e.Name() + "\n"
+	}
+	return out
+}
+
+func TestReaddirAll(t *testing.T) {
 	defer removeTestDir(t)
 	for _, fs := range Fss {
 		root, err := fs.Open(testDir)
@@ -389,12 +478,12 @@
 }
 
 func removeTestDir(t *testing.T) {
-	// for _, fs := range Fss {
-	// 	err := fs.RemoveAll(testDir)
-	// 	if err != nil {
-	// 		t.Fatal(err)
-	// 	}
-	// }
+	for _, fs := range Fss {
+		err := fs.RemoveAll(testDir)
+		if err != nil {
+			t.Fatal(err)
+		}
+	}
 }
 
 func newFile(testName string, fs Fs, t *testing.T) (f File) {
diff --git a/memfile.go b/memfile.go
index 505b4f1..90a5ae0 100644
--- a/memfile.go
+++ b/memfile.go
@@ -35,14 +35,15 @@
 
 type InMemoryFile struct {
 	sync.Mutex
-	at      int64
-	name    string
-	data    []byte
-	memDir  MemDir
-	dir     bool
-	closed  bool
-	mode    os.FileMode
-	modtime time.Time
+	at           int64
+	name         string
+	data         []byte
+	memDir       MemDir
+	dir          bool
+	closed       bool
+	mode         os.FileMode
+	modtime      time.Time
+	readDirCount int64
 }
 
 func MemFileCreate(name string) *InMemoryFile {
@@ -51,6 +52,7 @@
 
 func (f *InMemoryFile) Open() error {
 	atomic.StoreInt64(&f.at, 0)
+	atomic.StoreInt64(&f.readDirCount, 0)
 	f.Lock()
 	f.closed = false
 	f.Unlock()
@@ -58,7 +60,6 @@
 }
 
 func (f *InMemoryFile) Close() error {
-	atomic.StoreInt64(&f.at, 0)
 	f.Lock()
 	f.closed = true
 	f.Unlock()
@@ -74,29 +75,31 @@
 }
 
 func (f *InMemoryFile) Readdir(count int) (res []os.FileInfo, err error) {
-	files := f.memDir.Files()
-	limit := len(files)
+	var outLength int64
 
-	if len(files) == 0 {
-		return
-	}
-
+	f.Lock()
+	files := f.memDir.Files()[f.readDirCount:]
 	if count > 0 {
-		limit = count
+		if len(files) < count {
+			outLength = int64(len(files))
+		} else {
+			outLength = int64(count)
+		}
+		if len(files) == 0 {
+			err = io.EOF
+		}
+	} else {
+		outLength = int64(len(files))
+	}
+	f.readDirCount += outLength
+	f.Unlock()
+
+	res = make([]os.FileInfo, outLength)
+	for i := range res {
+		res[i], _ = files[i].Stat()
 	}
 
-	if len(files) < limit {
-		err = io.EOF
-	}
-
-	res = make([]os.FileInfo, f.memDir.Len())
-
-	i := 0
-	for _, file := range f.memDir.Files() {
-		res[i], _ = file.Stat()
-		i++
-	}
-	return res, nil
+	return res, err
 }
 
 func (f *InMemoryFile) Readdirnames(n int) (names []string, err error) {
diff --git a/memmap.go b/memmap.go
index c7b132c..5020e4c 100644
--- a/memmap.go
+++ b/memmap.go
@@ -20,6 +20,7 @@
 	"os"
 	"path"
 	"path/filepath"
+	"sort"
 	"strings"
 	"sync"
 	"time"
@@ -65,9 +66,17 @@
 	for _, f := range m {
 		files = append(files, f)
 	}
+	sort.Sort(filesSorter(files))
 	return files
 }
 
+type filesSorter []File
+
+// implement sort.Interface for []File
+func (s filesSorter) Len() int           { return len(s) }
+func (s filesSorter) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
+func (s filesSorter) Less(i, j int) bool { return s[i].Name() < s[j].Name() }
+
 func (m MemDirMap) Names() (names []string) {
 	for x := range m {
 		names = append(names, x)
@@ -95,6 +104,9 @@
 		return
 	}
 	parent := m.findParent(f)
+	if parent == nil {
+		log.Fatal("parent of ", f.Name(), " is nil")
+	}
 	pmem := parent.(*InMemoryFile)
 	pmem.memDir.Remove(f)
 }
@@ -113,11 +125,10 @@
 	if f == nil {
 		return
 	}
-	var err error
 	parent := m.findParent(f)
 	if parent == nil {
 		pdir := filepath.Dir(path.Clean(f.Name()))
-		err = m.lockfreeMkdir(pdir, 0777)
+		err := m.lockfreeMkdir(pdir, 0777)
 		if err != nil {
 			log.Println("Mkdir error:", err)
 			return
@@ -211,6 +222,10 @@
 }
 
 func (m *MemMapFs) RemoveAll(path string) error {
+	m.lock()
+	m.unRegisterWithParent(path)
+	m.unlock()
+
 	m.rlock()
 	defer m.runlock()
 
@@ -218,7 +233,6 @@
 		if strings.HasPrefix(p, path) {
 			m.runlock()
 			m.lock()
-			m.unRegisterWithParent(p)
 			delete(m.getData(), p)
 			m.unlock()
 			m.rlock()