diff --git a/headers/private/kernel/util/AVLTree.h b/headers/private/kernel/util/AVLTree.h
new file mode 100644
index 0000000000..eb8964e627
--- /dev/null
+++ b/headers/private/kernel/util/AVLTree.h
@@ -0,0 +1,366 @@
+/*
+ * Copyright 2003-2009, Ingo Weinhold <ingo_weinhold@gmx.de>.
+ * Distributed under the terms of the MIT License.
+ */
+#ifndef _KERNEL_UTIL_AVL_TREE_H
+#define _KERNEL_UTIL_AVL_TREE_H
+
+
+#include <util/AVLTreeBase.h>
+
+
+/*
+	To be implemented by the definition:
+
+	typedef int	Key;
+	typedef Foo	Value;
+
+	AVLTreeNode*		GetAVLTreeNode(Value* value) const;
+	Value*				GetValue(AVLTreeNode* node) const;
+	int					Compare(const Key& a, const Value* b) const;
+	int					Compare(const Value* a, const Value* b) const;
+*/
+
+
+
+template<typename Definition>
+class AVLTree : protected AVLTreeCompare {
+private:
+	typedef typename Definition::Key	Key;
+	typedef typename Definition::Value	Value;
+
+public:
+	class Iterator;
+	class ConstIterator;
+
+public:
+								AVLTree();
+								AVLTree(const Definition& definition);
+	virtual						~AVLTree();
+
+	inline	int					Count() const	{ return fTree.Count(); }
+	inline	bool				IsEmpty() const	{ return fTree.IsEmpty(); }
+	inline	void				Clear();
+
+			Value*				RootNode() const;
+
+	inline	Iterator			GetIterator();
+	inline	ConstIterator		GetIterator() const;
+
+	inline	Iterator			GetIterator(Value* value);
+	inline	ConstIterator		GetIterator(Value* value) const;
+
+			Value*				Find(const Key& key) const;
+			Value*				FindClosest(const Key& key, bool less) const;
+
+			status_t			Insert(Value* value, Iterator* iterator = NULL);
+			Value*				Remove(const Key& key);
+			bool				Remove(Value* key);
+
+			void				CheckTree() const	{ fTree.CheckTree(); }
+
+protected:
+	// AVLTreeCompare
+	virtual	int					CompareKeyNode(const void* key,
+									const AVLTreeNode* node);
+	virtual	int					CompareNodes(const AVLTreeNode* node1,
+									const AVLTreeNode* node2);
+
+	// definition shortcuts
+	inline	AVLTreeNode*		_GetAVLTreeNode(Value* value) const;
+	inline	Value*				_GetValue(const AVLTreeNode* node) const;
+	inline	int					_Compare(const Key& a, const Value* b);
+	inline	int					_Compare(const Value* a, const Value* b);
+
+protected:
+			friend class Iterator;
+			friend class ConstIterator;
+
+			AVLTreeBase			fTree;
+			Definition			fDefinition;
+
+public:
+	// (need to implement it here, otherwise gcc 2.95.3 chokes)
+	class Iterator : public ConstIterator {
+	public:
+		inline Iterator()
+			:
+			ConstIterator()
+		{
+		}
+
+		inline Iterator(const Iterator& other)
+			:
+			ConstIterator(other)
+		{
+		}
+
+		inline void Remove()
+		{
+			if (AVLTreeNode* node = ConstIterator::fTreeIterator.Remove()) {
+				AVLTree<Definition>* parent
+					= const_cast<AVLTree<Definition>*>(
+						ConstIterator::fParent);
+			}
+		}
+
+	private:
+		inline Iterator(AVLTree<Definition>* parent,
+			const AVLTreeIterator& treeIterator)
+			: ConstIterator(parent, treeIterator)
+		{
+		}
+
+		friend class AVLTree<Definition>;
+	};
+};
+
+
+template<typename Definition>
+class AVLTree<Definition>::ConstIterator {
+public:
+	inline ConstIterator()
+		:
+		fParent(NULL),
+		fTreeIterator()
+	{
+	}
+
+	inline ConstIterator(const ConstIterator& other)
+		:
+		fParent(other.fParent),
+		fTreeIterator(other.fTreeIterator)
+	{
+	}
+
+	inline bool HasCurrent() const
+	{
+		return fTreeIterator.Current();
+	}
+
+	inline Value* Current()
+	{
+		if (AVLTreeNode* node = fTreeIterator.Current())
+			return fParent->_GetValue(node);
+		return NULL;
+	}
+
+	inline bool HasNext() const
+	{
+		return fTreeIterator.HasNext();
+	}
+
+	inline Value* Next()
+	{
+		if (AVLTreeNode* node = fTreeIterator.Next())
+			return fParent->_GetValue(node);
+		return NULL;
+	}
+
+	inline Value* Previous()
+	{
+		if (AVLTreeNode* node = fTreeIterator.Previous())
+			return fParent->_GetValue(node);
+		return NULL;
+	}
+
+	inline ConstIterator& operator=(const ConstIterator& other)
+	{
+		fParent = other.fParent;
+		fTreeIterator = other.fTreeIterator;
+		return *this;
+	}
+
+protected:
+	inline ConstIterator(const AVLTree<Definition>* parent,
+		const AVLTreeIterator& treeIterator)
+	{
+		fParent = parent;
+		fTreeIterator = treeIterator;
+	}
+
+	friend class AVLTree<Definition>;
+
+	const AVLTree<Definition>*	fParent;
+	AVLTreeIterator				fTreeIterator;
+};
+
+
+template<typename Definition>
+AVLTree<Definition>::AVLTree()
+	:
+	fTree(this),
+	fDefinition()
+{
+}
+
+
+template<typename Definition>
+AVLTree<Definition>::AVLTree(const Definition& definition)
+	:
+	fTree(this),
+	fDefinition(definition)
+{
+}
+
+
+template<typename Definition>
+AVLTree<Definition>::~AVLTree()
+{
+}
+
+
+template<typename Definition>
+inline void
+AVLTree<Definition>::Clear()
+{
+	fTree.MakeEmpty();
+}
+
+
+template<typename Definition>
+inline typename AVLTree<Definition>::Value*
+AVLTree<Definition>::RootNode() const
+{
+	if (AVLTreeNode* root = fTree.Root())
+		return _GetValue(root);
+	return NULL;
+}
+
+
+template<typename Definition>
+inline typename AVLTree<Definition>::Iterator
+AVLTree<Definition>::GetIterator()
+{
+	return Iterator(this, fTree.GetIterator());
+}
+
+
+template<typename Definition>
+inline typename AVLTree<Definition>::ConstIterator
+AVLTree<Definition>::GetIterator() const
+{
+	return ConstIterator(this, fTree.GetIterator());
+}
+
+
+template<typename Definition>
+inline typename AVLTree<Definition>::Iterator
+AVLTree<Definition>::GetIterator(Value* value)
+{
+	return Iterator(this, fTree.GetIterator(_GetAVLTreeNode(value)));
+}
+
+
+template<typename Definition>
+inline typename AVLTree<Definition>::ConstIterator
+AVLTree<Definition>::GetIterator(Value* value) const
+{
+	return ConstIterator(this, fTree.GetIterator(_GetAVLTreeNode(value)));
+}
+
+
+template<typename Definition>
+typename AVLTree<Definition>::Value*
+AVLTree<Definition>::Find(const Key& key) const
+{
+	if (AVLTreeNode* node = fTree.Find(&key))
+		return _GetValue(node);
+	return NULL;
+}
+
+
+template<typename Definition>
+typename AVLTree<Definition>::Value*
+AVLTree<Definition>::FindClosest(const Key& key, bool less) const
+{
+	if (AVLTreeNode* node = fTree.FindClosest(&key, less))
+		return _GetValue(node);
+	return NULL;
+}
+
+
+template<typename Definition>
+status_t
+AVLTree<Definition>::Insert(Value* value, Iterator* iterator)
+{
+	AVLTreeNode* node = _GetAVLTreeNode(value);
+	status_t error = fTree.Insert(node);
+	if (error != B_OK)
+		return error;
+
+	if (iterator != NULL)
+		*iterator = Iterator(this, fTree.GetIterator(node));
+
+	return B_OK;
+}
+
+
+template<typename Definition>
+typename AVLTree<Definition>::Value*
+AVLTree<Definition>::Remove(const Key& key)
+{
+	AVLTreeNode* node = fTree.Remove(&key);
+	return node != NULL ? _GetValue(node) : NULL;
+}
+
+
+template<typename Definition>
+bool
+AVLTree<Definition>::Remove(Value* value)
+{
+	return fTree.Remove(_GetAVLTreeNode(value));
+}
+
+
+template<typename Definition>
+int
+AVLTree<Definition>::CompareKeyNode(const void* key,
+	const AVLTreeNode* node)
+{
+	return _Compare(*(const Key*)key, _GetValue(node));
+}
+
+
+template<typename Definition>
+int
+AVLTree<Definition>::CompareNodes(const AVLTreeNode* node1,
+	const AVLTreeNode* node2)
+{
+	return _Compare(_GetValue(node1), _GetValue(node2));
+}
+
+
+template<typename Definition>
+inline AVLTreeNode*
+AVLTree<Definition>::_GetAVLTreeNode(Value* value) const
+{
+	return fDefinition.GetAVLTreeNode(value);
+}
+
+
+template<typename Definition>
+inline typename AVLTree<Definition>::Value*
+AVLTree<Definition>::_GetValue(const AVLTreeNode* node) const
+{
+	return fDefinition.GetValue(const_cast<AVLTreeNode*>(node));
+}
+
+
+template<typename Definition>
+inline int
+AVLTree<Definition>::_Compare(const Key& a, const Value* b)
+{
+	return fDefinition.Compare(a, b);
+}
+
+
+template<typename Definition>
+inline int
+AVLTree<Definition>::_Compare(const Value* a, const Value* b)
+{
+	return fDefinition.Compare(a, b);
+}
+
+
+#endif	// _KERNEL_UTIL_AVL_TREE_H
diff --git a/headers/private/kernel/util/AVLTreeBase.h b/headers/private/kernel/util/AVLTreeBase.h
new file mode 100644
index 0000000000..6c9bd7bbad
--- /dev/null
+++ b/headers/private/kernel/util/AVLTreeBase.h
@@ -0,0 +1,205 @@
+/*
+ * Copyright 2003-2009, Ingo Weinhold <ingo_weinhold@gmx.de>.
+ * Distributed under the terms of the MIT License.
+ */
+#ifndef _KERNEL_UTIL_AVL_TREE_BASE_H
+#define _KERNEL_UTIL_AVL_TREE_BASE_H
+
+
+#include <SupportDefs.h>
+
+
+class AVLTreeIterator;
+
+
+struct AVLTreeNode {
+	AVLTreeNode*	parent;
+	AVLTreeNode*	left;
+	AVLTreeNode*	right;
+	int				balance_factor;
+};
+
+
+class AVLTreeCompare {
+public:
+	virtual						~AVLTreeCompare();
+
+	virtual	int					CompareKeyNode(const void* key,
+									const AVLTreeNode* node) = 0;
+	virtual	int					CompareNodes(const AVLTreeNode* node1,
+									const AVLTreeNode* node2) = 0;
+};
+
+
+class AVLTreeBase {
+public:
+								AVLTreeBase(AVLTreeCompare* compare);
+								~AVLTreeBase();
+
+	inline	int					Count() const	{ return fNodeCount; }
+	inline	bool				IsEmpty() const	{ return (fNodeCount == 0); }
+			void				MakeEmpty();
+
+	inline	AVLTreeNode*		Root() const	{ return fRoot; }
+
+			AVLTreeNode*		LeftMost(AVLTreeNode* node) const;
+			AVLTreeNode*		RightMost(AVLTreeNode* node) const;
+
+			AVLTreeNode*		Previous(AVLTreeNode* node) const;
+			AVLTreeNode*		Next(AVLTreeNode* node) const;
+
+	inline	AVLTreeIterator		GetIterator() const;
+	inline	AVLTreeIterator		GetIterator(AVLTreeNode* node) const;
+
+			AVLTreeNode*		Find(const void* key) const;
+			AVLTreeNode*		FindClosest(const void* key, bool less) const;
+
+			status_t			Insert(AVLTreeNode* element);
+			AVLTreeNode*		Remove(const void* key);
+			bool				Remove(AVLTreeNode* element);
+
+			void				CheckTree() const;
+
+private:
+			enum {
+				NOT_FOUND		= -3,
+				DUPLICATE		= -2,
+				NO_MEMORY		= -1,
+				OK				= 0,
+				HEIGHT_CHANGED	= 1,
+
+				LEFT			= -1,
+				BALANCED		= 0,
+				RIGHT			= 1,
+			};
+
+			// rotations
+			void				_RotateRight(AVLTreeNode** nodeP);
+			void				_RotateLeft(AVLTreeNode** nodeP);
+
+			// insert
+			int					_BalanceInsertLeft(AVLTreeNode** node);
+			int					_BalanceInsertRight(AVLTreeNode** node);
+			int					_Insert(AVLTreeNode* nodeToInsert);
+
+			// remove
+			int					_BalanceRemoveLeft(AVLTreeNode** node);
+			int					_BalanceRemoveRight(AVLTreeNode** node);
+			int					_RemoveRightMostChild(AVLTreeNode** node,
+									AVLTreeNode** foundNode);
+			int					_Remove(AVLTreeNode* node);
+
+			int					_CheckTree(AVLTreeNode* parent,
+									AVLTreeNode* node, int& _nodeCount) const;
+
+			AVLTreeNode*		fRoot;
+			int					fNodeCount;
+			AVLTreeCompare*		fCompare;
+};
+
+
+// AVLTreeIterator
+class AVLTreeIterator {
+public:
+	inline AVLTreeIterator()
+		:
+		fParent(NULL),
+		fCurrent(NULL),
+		fNext(NULL)
+	{
+	}
+
+	inline AVLTreeIterator(const AVLTreeIterator& other)
+		:
+		fParent(other.fParent),
+		fCurrent(other.fCurrent),
+		fNext(other.fNext)
+	{
+	}
+
+	inline AVLTreeNode* Current() const
+	{
+		return fCurrent;
+	}
+
+	inline bool HasNext() const
+	{
+		return fNext;
+	}
+
+	inline AVLTreeNode* Next()
+	{
+		fCurrent = fNext;
+
+		if (fNext)
+			fNext = fParent->Next(fNext);
+
+		return fCurrent;
+	}
+
+	inline AVLTreeNode* Previous()
+	{
+		if (fCurrent) {
+			fNext = fCurrent;
+			fCurrent = fParent->Previous(fCurrent);
+		} else if (fNext)
+			fCurrent = fParent->Previous(fNext);
+
+		return fCurrent;
+	}
+
+	inline AVLTreeNode* Remove()
+	{
+		if (!fCurrent)
+			return NULL;
+
+		AVLTreeNode* node = fCurrent;
+		fCurrent = NULL;
+
+		return (const_cast<AVLTreeBase*>(fParent)->Remove(node) ? node : NULL);
+	}
+
+	inline AVLTreeIterator& operator=(const AVLTreeIterator& other)
+	{
+		fParent = other.fParent;
+		fCurrent = other.fCurrent;
+		fNext = other.fNext;
+		return *this;
+	}
+
+private:
+	inline AVLTreeIterator(const AVLTreeBase* parent, AVLTreeNode* current,
+			AVLTreeNode* next)
+		:
+		fParent(parent),
+		fCurrent(current),
+		fNext(next)
+	{
+	}
+
+protected:
+	friend class AVLTreeBase;
+
+	const AVLTreeBase*	fParent;
+	AVLTreeNode*		fCurrent;
+	AVLTreeNode*		fNext;
+};
+
+
+// GetIterator
+inline AVLTreeIterator
+AVLTreeBase::GetIterator() const
+{
+	return AVLTreeIterator(this, NULL, LeftMost(fRoot));
+}
+
+
+// GetIterator
+inline AVLTreeIterator
+AVLTreeBase::GetIterator(AVLTreeNode* node) const
+{
+	return AVLTreeIterator(this, node, Next(node));
+}
+
+
+#endif	// _KERNEL_UTIL_AVL_TREE_BASE_H
diff --git a/headers/private/kernel/util/AVLTreeMap.h b/headers/private/kernel/util/AVLTreeMap.h
index da25650d7b..a6a978572b 100644
--- a/headers/private/kernel/util/AVLTreeMap.h
+++ b/headers/private/kernel/util/AVLTreeMap.h
@@ -1,209 +1,13 @@
 /*
- * Copyright 2003-2007, Ingo Weinhold <bonefish@cs.tu-berlin.de>.
+ * Copyright 2003-2009, Ingo Weinhold <ingo_weinhold@gmx.de>.
  * Distributed under the terms of the MIT License.
  */
-#ifndef _AVL_TREE_MAP_H
-#define _AVL_TREE_MAP_H
+#ifndef _KERNEL_UTIL_AVL_TREE_MAP_H
+#define _KERNEL_UTIL_AVL_TREE_MAP_H
 
 
-#include <OS.h>
-#include <util/kernel_cpp.h>
-
 #include <util/MallocFreeAllocator.h>
-
-
-// maximal height of a tree
-static const int kMaxAVLTreeHeight = 32;
-
-class AVLTreeIterator;
-
-
-// AVLTreeNode
-struct AVLTreeNode {
-	AVLTreeNode*	parent;
-	AVLTreeNode*	left;
-	AVLTreeNode*	right;
-	int				balance_factor;
-};
-
-
-// AVLTreeCompare
-class AVLTreeCompare {
-public:
-	virtual						~AVLTreeCompare();
-
-	virtual	int					CompareKeyNode(const void* key,
-									const AVLTreeNode* node) = 0;
-	virtual	int					CompareNodes(const AVLTreeNode* node1,
-									const AVLTreeNode* node2) = 0;
-};
-
-
-// AVLTree
-class AVLTree {
-public:
-								AVLTree(AVLTreeCompare* compare);
-								~AVLTree();
-
-	inline	int					Count() const	{ return fNodeCount; }
-	inline	bool				IsEmpty() const	{ return (fNodeCount == 0); }
-			void				MakeEmpty();
-
-	inline	AVLTreeNode*		Root() const	{ return fRoot; }
-
-			AVLTreeNode*		LeftMost(AVLTreeNode* node) const;
-			AVLTreeNode*		RightMost(AVLTreeNode* node) const;
-
-			AVLTreeNode*		Previous(AVLTreeNode* node) const;
-			AVLTreeNode*		Next(AVLTreeNode* node) const;
-
-	inline	AVLTreeIterator		GetIterator() const;
-	inline	AVLTreeIterator		GetIterator(AVLTreeNode* node) const;
-
-			AVLTreeNode*		Find(const void* key);
-			AVLTreeNode*		FindClose(const void* key, bool less);
-
-			status_t			Insert(AVLTreeNode* element);
-			AVLTreeNode*		Remove(const void* key);
-			bool				Remove(AVLTreeNode* element);
-
-private:
-			enum {
-				NOT_FOUND		= -3,
-				DUPLICATE		= -2,
-				NO_MEMORY		= -1,
-				OK				= 0,
-				HEIGHT_CHANGED	= 1,
-
-				LEFT			= -1,
-				BALANCED		= 0,
-				RIGHT			= 1,
-			};
-
-			// rotations
-			void				_RotateRight(AVLTreeNode** nodeP);
-			void				_RotateLeft(AVLTreeNode** nodeP);
-
-			// insert
-			int					_BalanceInsertLeft(AVLTreeNode** node);
-			int					_BalanceInsertRight(AVLTreeNode** node);
-			int					_Insert(AVLTreeNode* nodeToInsert);
-
-			// remove
-			int					_BalanceRemoveLeft(AVLTreeNode** node);
-			int					_BalanceRemoveRight(AVLTreeNode** node);
-			int					_RemoveRightMostChild(AVLTreeNode** node,
-									AVLTreeNode** foundNode);
-			int					_Remove(AVLTreeNode* node);
-
-			AVLTreeNode*		fRoot;
-			int					fNodeCount;
-			AVLTreeCompare*		fCompare;
-};
-
-
-// AVLTreeIterator
-class AVLTreeIterator {
-public:
-	inline AVLTreeIterator()
-		: fParent(NULL),
-		  fCurrent(NULL),
-		  fNext(NULL)
-	{
-	}
-
-	inline AVLTreeIterator(const AVLTreeIterator& other)
-		: fParent(other.fParent),
-		  fCurrent(other.fCurrent),
-		  fNext(other.fNext)
-	{
-	}
-
-	inline AVLTreeNode* Current() const
-	{
-		return fCurrent;
-	}
-
-	inline bool HasNext() const
-	{
-		return fNext;
-	}
-
-	inline AVLTreeNode* Next()
-	{
-		fCurrent = fNext;
-
-		if (fNext)
-			fNext = fParent->Next(fNext);
-
-		return fCurrent;
-	}
-
-	inline AVLTreeNode* Previous()
-	{
-		if (fCurrent) {
-			fNext = fCurrent;
-			fCurrent = fParent->Previous(fCurrent);
-		} else if (fNext)
-			fCurrent = fParent->Previous(fNext);
-
-		return fCurrent;
-	}
-
-	inline AVLTreeNode* Remove()
-	{
-		if (!fCurrent)
-			return NULL;
-
-		AVLTreeNode* node = fCurrent;
-		fCurrent = NULL;
-
-		return (const_cast<AVLTree*>(fParent)->Remove(node) ? node : NULL);
-	}
-
-	inline AVLTreeIterator& operator=(const AVLTreeIterator& other)
-	{
-		fParent = other.fParent;
-		fCurrent = other.fCurrent;
-		fNext = other.fNext;
-		return *this;
-	}
-
-private:
-	inline AVLTreeIterator(const AVLTree* parent, AVLTreeNode* current,
-			AVLTreeNode* next)
-		: fParent(parent),
-		  fCurrent(current),
-		  fNext(next)
-	{
-	}
-
-protected:
-	friend class AVLTree;
-
-	const AVLTree*	fParent;
-	AVLTreeNode*	fCurrent;
-	AVLTreeNode*	fNext;
-};
-
-
-// GetIterator
-inline AVLTreeIterator
-AVLTree::GetIterator() const
-{
-	return AVLTreeIterator(this, NULL, LeftMost(fRoot));
-}
-
-
-// GetIterator
-inline AVLTreeIterator
-AVLTree::GetIterator(AVLTreeNode* node) const
-{
-	return AVLTreeIterator(this, node, Next(node));
-}
-
-
-// #pragma mark - AVLTreeMap and friends
+#include <util/AVLTreeBase.h>
 
 
 // strategies
@@ -299,7 +103,7 @@ protected:
 			friend class Iterator;
 			friend class ConstIterator;
 
-			AVLTree				fTree;
+			AVLTreeBase			fTree;
 			NodeStrategy		fStrategy;
 
 public:
@@ -518,7 +322,7 @@ _AVL_TREE_MAP_TEMPLATE_LIST
 typename _AVL_TREE_MAP_CLASS_NAME::Iterator
 _AVL_TREE_MAP_CLASS_NAME::FindClose(const Key& key, bool less)
 {
-	if (AVLTreeNode* node = fTree.FindClose(&key, less))
+	if (AVLTreeNode* node = fTree.FindClosest(&key, less))
 		return Iterator(this, fTree.GetIterator(node));
 	return Iterator();
 }
@@ -776,4 +580,4 @@ private:
 };
 }
 
-#endif	// _AVL_TREE_MAP_H
+#endif	// _KERNEL_UTIL_AVL_TREE_MAP_H
diff --git a/src/system/kernel/util/AVLTreeMap.cpp b/src/system/kernel/util/AVLTreeBase.cpp
similarity index 78%
rename from src/system/kernel/util/AVLTreeMap.cpp
rename to src/system/kernel/util/AVLTreeBase.cpp
index e3564cd3e5..91c3ff096e 100644
--- a/src/system/kernel/util/AVLTreeMap.cpp
+++ b/src/system/kernel/util/AVLTreeBase.cpp
@@ -1,9 +1,32 @@
 /*
- * Copyright 2003-2007, Ingo Weinhold <bonefish@cs.tu-berlin.de>.
+ * Copyright 2003-2009, Ingo Weinhold <ingo_weinhold@gmx.de>.
  * Distributed under the terms of the MIT License.
  */
 
-#include <util/AVLTreeMap.h>
+
+#include <util/AVLTreeBase.h>
+
+#include <algorithm>
+
+#include <KernelExport.h>
+
+
+#ifdef _KERNEL_MODE
+#	define CHECK_FAILED(message...)	panic(message)
+#else
+#	include <stdio.h>
+#	include <OS.h>
+#	define CHECK_FAILED(message...)					\
+		do {										\
+			fprintf(stderr, message);				\
+			fprintf(stderr, "\n");					\
+			debugger("AVLTreeBase check failed");	\
+		} while (false)
+#endif
+
+
+// maximal height of a tree
+static const int kMaxAVLTreeHeight = 32;
 
 
 // #pragma mark - AVLTreeCompare
@@ -14,10 +37,10 @@ AVLTreeCompare::~AVLTreeCompare()
 }
 
 
-// #pragma mark - AVLTree
+// #pragma mark - AVLTreeBase
 
 
-AVLTree::AVLTree(AVLTreeCompare* compare)
+AVLTreeBase::AVLTreeBase(AVLTreeCompare* compare)
 	: fRoot(NULL),
 	  fNodeCount(0),
 	  fCompare(compare)
@@ -25,77 +48,21 @@ AVLTree::AVLTree(AVLTreeCompare* compare)
 }
 
 
-AVLTree::~AVLTree()
+AVLTreeBase::~AVLTreeBase()
 {
 }
 
 
 void
-AVLTree::MakeEmpty()
+AVLTreeBase::MakeEmpty()
 {
 	fRoot = NULL;
 	fNodeCount = 0;
 }
 
 
-status_t
-AVLTree::Insert(AVLTreeNode* nodeToInsert)
-{
-	int result = _Insert(nodeToInsert);
-	switch (result) {
-		case OK:
-		case HEIGHT_CHANGED:
-			return B_OK;
-		case NO_MEMORY:
-			return B_NO_MEMORY;
-		case DUPLICATE:
-		default:
-			return B_BAD_VALUE;
-	}
-}
-
-
 AVLTreeNode*
-AVLTree::Remove(const void* key)
-{
-	// find node
-	AVLTreeNode* node = fRoot;
-	while (node) {
-		int cmp = fCompare->CompareKeyNode(key, node);
-		if (cmp == 0)
-			break;
-		else {
-			if (cmp < 0)
-				node = node->left;
-			else
-				node = node->right;
-		}
-	}
-
-	// remove it
-	if (node)
-		_Remove(node);
-
-	return node;
-}
-
-
-bool
-AVLTree::Remove(AVLTreeNode* node)
-{
-	switch (_Remove(node)) {
-		case OK:
-		case HEIGHT_CHANGED:
-			return true;
-		case NOT_FOUND:
-		default:
-			return false;
-	}
-}
-
-
-AVLTreeNode*
-AVLTree::LeftMost(AVLTreeNode* node) const
+AVLTreeBase::LeftMost(AVLTreeNode* node) const
 {
 	if (node) {
 		while (node->left)
@@ -107,7 +74,7 @@ AVLTree::LeftMost(AVLTreeNode* node) const
 
 
 AVLTreeNode*
-AVLTree::RightMost(AVLTreeNode* node) const
+AVLTreeBase::RightMost(AVLTreeNode* node) const
 {
 	if (node) {
 		while (node->right)
@@ -119,7 +86,7 @@ AVLTree::RightMost(AVLTreeNode* node) const
 
 
 AVLTreeNode*
-AVLTree::Previous(AVLTreeNode* node) const
+AVLTreeBase::Previous(AVLTreeNode* node) const
 {
 	if (node) {
 		// The previous node cannot be in the right subtree.
@@ -144,7 +111,7 @@ AVLTree::Previous(AVLTreeNode* node) const
 
 
 AVLTreeNode*
-AVLTree::Next(AVLTreeNode* node) const
+AVLTreeBase::Next(AVLTreeNode* node) const
 {
 	if (node) {
 		// The next node cannot be in the left subtree.
@@ -169,7 +136,7 @@ AVLTree::Next(AVLTreeNode* node) const
 
 
 AVLTreeNode*
-AVLTree::Find(const void* key)
+AVLTreeBase::Find(const void* key) const
 {
 	AVLTreeNode* node = fRoot;
 
@@ -189,7 +156,7 @@ AVLTree::Find(const void* key)
 
 
 AVLTreeNode*
-AVLTree::FindClose(const void* key, bool less)
+AVLTreeBase::FindClosest(const void* key, bool less) const
 {
 	AVLTreeNode* node = fRoot;
 	AVLTreeNode* parent = NULL;
@@ -225,8 +192,76 @@ AVLTree::FindClose(const void* key, bool less)
 }
 
 
+status_t
+AVLTreeBase::Insert(AVLTreeNode* nodeToInsert)
+{
+	int result = _Insert(nodeToInsert);
+	switch (result) {
+		case OK:
+		case HEIGHT_CHANGED:
+			return B_OK;
+		case NO_MEMORY:
+			return B_NO_MEMORY;
+		case DUPLICATE:
+		default:
+			return B_BAD_VALUE;
+	}
+}
+
+
+AVLTreeNode*
+AVLTreeBase::Remove(const void* key)
+{
+	// find node
+	AVLTreeNode* node = fRoot;
+	while (node) {
+		int cmp = fCompare->CompareKeyNode(key, node);
+		if (cmp == 0)
+			break;
+		else {
+			if (cmp < 0)
+				node = node->left;
+			else
+				node = node->right;
+		}
+	}
+
+	// remove it
+	if (node)
+		_Remove(node);
+
+	return node;
+}
+
+
+bool
+AVLTreeBase::Remove(AVLTreeNode* node)
+{
+	switch (_Remove(node)) {
+		case OK:
+		case HEIGHT_CHANGED:
+			return true;
+		case NOT_FOUND:
+		default:
+			return false;
+	}
+}
+
+
 void
-AVLTree::_RotateRight(AVLTreeNode** nodeP)
+AVLTreeBase::CheckTree() const
+{
+	int nodeCount = 0;
+	_CheckTree(NULL, fRoot, nodeCount);
+	if (nodeCount != fNodeCount) {
+		CHECK_FAILED("AVLTreeBase::CheckTree(): node count mismatch: %d vs %d",
+			nodeCount, fNodeCount);
+	}
+}
+
+
+void
+AVLTreeBase::_RotateRight(AVLTreeNode** nodeP)
 {
 	// rotate the nodes
 	AVLTreeNode* node = *nodeP;
@@ -257,7 +292,7 @@ AVLTree::_RotateRight(AVLTreeNode** nodeP)
 
 
 void
-AVLTree::_RotateLeft(AVLTreeNode** nodeP)
+AVLTreeBase::_RotateLeft(AVLTreeNode** nodeP)
 {
 	// rotate the nodes
 	AVLTreeNode* node = *nodeP;
@@ -288,7 +323,7 @@ AVLTree::_RotateLeft(AVLTreeNode** nodeP)
 
 
 int
-AVLTree::_BalanceInsertLeft(AVLTreeNode** node)
+AVLTreeBase::_BalanceInsertLeft(AVLTreeNode** node)
 {
 	if ((*node)->balance_factor < LEFT) {
 		// tree is left heavy
@@ -312,7 +347,7 @@ AVLTree::_BalanceInsertLeft(AVLTreeNode** node)
 
 
 int
-AVLTree::_BalanceInsertRight(AVLTreeNode** node)
+AVLTreeBase::_BalanceInsertRight(AVLTreeNode** node)
 {
 	if ((*node)->balance_factor > RIGHT) {
 		// tree is right heavy
@@ -336,7 +371,7 @@ AVLTree::_BalanceInsertRight(AVLTreeNode** node)
 
 
 int
-AVLTree::_Insert(AVLTreeNode* nodeToInsert)
+AVLTreeBase::_Insert(AVLTreeNode* nodeToInsert)
 {
 	struct node_info {
 		AVLTreeNode**	node;
@@ -378,10 +413,6 @@ AVLTree::_Insert(AVLTreeNode* nodeToInsert)
 	else
 		(*node)->parent = *top[-1].node;
 
-	// init the iterator
-//	if (iterator)
-//		*iterator = Iterator(this, *node);
-
 	// do the balancing
 	int result = HEIGHT_CHANGED;
 	while (result == HEIGHT_CHANGED && top != bottom) {
@@ -403,7 +434,7 @@ AVLTree::_Insert(AVLTreeNode* nodeToInsert)
 
 
 int
-AVLTree::_BalanceRemoveLeft(AVLTreeNode** node)
+AVLTreeBase::_BalanceRemoveLeft(AVLTreeNode** node)
 {
 	int result = HEIGHT_CHANGED;
 
@@ -430,7 +461,7 @@ AVLTree::_BalanceRemoveLeft(AVLTreeNode** node)
 
 
 int
-AVLTree::_BalanceRemoveRight(AVLTreeNode** node)
+AVLTreeBase::_BalanceRemoveRight(AVLTreeNode** node)
 {
 	int result = HEIGHT_CHANGED;
 
@@ -457,7 +488,7 @@ AVLTree::_BalanceRemoveRight(AVLTreeNode** node)
 
 
 int
-AVLTree::_RemoveRightMostChild(AVLTreeNode** node, AVLTreeNode** foundNode)
+AVLTreeBase::_RemoveRightMostChild(AVLTreeNode** node, AVLTreeNode** foundNode)
 {
 	AVLTreeNode** stack[kMaxAVLTreeHeight];
 	AVLTreeNode*** top = stack;
@@ -495,7 +526,7 @@ AVLTree::_RemoveRightMostChild(AVLTreeNode** node, AVLTreeNode** foundNode)
 
 
 int
-AVLTree::_Remove(AVLTreeNode* node)
+AVLTreeBase::_Remove(AVLTreeNode* node)
 {
 	if (!node)
 		return NOT_FOUND;
@@ -563,3 +594,36 @@ AVLTree::_Remove(AVLTreeNode* node)
 
 	return result;
 }
+
+
+int
+AVLTreeBase::_CheckTree(AVLTreeNode* parent, AVLTreeNode* node,
+	int& _nodeCount) const
+{
+	if (node == NULL) {
+		_nodeCount = 0;
+		return 0;
+	}
+
+	if (parent != node->parent) {
+		CHECK_FAILED("AVLTreeBase::_CheckTree(): node %p parent mismatch: "
+			"%p vs %p", node, parent, node->parent);
+	}
+
+	int leftNodeCount;
+	int leftDepth = _CheckTree(node, node->left, leftNodeCount);
+
+	int rightNodeCount;
+	int rightDepth = _CheckTree(node, node->right, rightNodeCount);
+
+	int balance = rightDepth - leftDepth;
+	if (balance < LEFT || balance > RIGHT) {
+		CHECK_FAILED("AVLTreeBase::_CheckTree(): unbalanced subtree: %p", node);
+	} else if (balance != node->balance_factor) {
+		CHECK_FAILED("AVLTreeBase::_CheckTree(): subtree %p balance mismatch: "
+			"%d vs %d", node, balance, node->balance_factor);
+	}
+
+	_nodeCount = leftNodeCount + rightNodeCount + 1;
+	return std::max(leftDepth, rightDepth) + 1;
+}
diff --git a/src/system/kernel/util/Jamfile b/src/system/kernel/util/Jamfile
index ea99997063..60616440a9 100644
--- a/src/system/kernel/util/Jamfile
+++ b/src/system/kernel/util/Jamfile
@@ -3,7 +3,7 @@ SubDir HAIKU_TOP src system kernel util ;
 UsePrivateHeaders [ FDirName kernel util ] ;
 
 KernelMergeObject kernel_util.o :
-	AVLTreeMap.cpp
+	AVLTreeBase.cpp
 	kernel_cpp.cpp
 	khash.cpp
 	list.cpp