diff --git a/headers/private/kernel/disk_device_manager/KDiskDeviceManager.h b/headers/private/kernel/disk_device_manager/KDiskDeviceManager.h
index cf4a62d964..d604828007 100644
--- a/headers/private/kernel/disk_device_manager/KDiskDeviceManager.h
+++ b/headers/private/kernel/disk_device_manager/KDiskDeviceManager.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2004-2007, Haiku, Inc. All rights reserved.
+ * Copyright 2004-2009, Haiku, Inc. All rights reserved.
  * Copyright 2003-2004, Ingo Weinhold, bonefish@cs.tu-berlin.de. All rights reserved.
  *
  * Distributed under the terms of the MIT License.
@@ -10,6 +10,7 @@
 
 #include <disk_device_manager.h>
 #include <Locker.h>
+#include <Notifications.h>
 
 
 namespace BPrivate {
@@ -40,6 +41,9 @@ public:
 
 	// Disk Device / Partition Management
 
+	DefaultUserNotificationService& Notifications();
+	void Notify(const KMessage& event, uint32 eventMask);
+
 	// manager must be locked
 	KDiskDevice *FindDevice(const char *path);
 	KDiskDevice *FindDevice(partition_id id, bool deviceOnly = true);
@@ -104,6 +108,7 @@ private:
 	struct PartitionSet;
 	class DiskSystemWatcher;
 	class DeviceWatcher;
+	class DiskNotifications;
 
 	static status_t _CheckMediaStatusDaemon(void* self);
 	status_t _CheckMediaStatus();
@@ -126,6 +131,8 @@ private:
 
 	status_t _AddRemoveMonitoring(const char *path, bool add);
 
+	void _NotifyDeviceEvent(KDiskDevice* device, int32 event, uint32 mask);
+
 	BLocker						fLock;
 	DeviceMap					*fDevices;
 	PartitionMap				*fPartitions;
@@ -135,6 +142,7 @@ private:
 	volatile bool				fTerminating;
 	DiskSystemWatcher			*fDiskSystemWatcher;
 	DeviceWatcher				*fDeviceWatcher;
+	DiskNotifications*			fNotifications;
 
 	static KDiskDeviceManager	*sDefaultManager;
 };
diff --git a/headers/private/kernel/disk_device_manager/ddm_userland_interface.h b/headers/private/kernel/disk_device_manager/ddm_userland_interface.h
index 93233e3b23..197ac53a65 100644
--- a/headers/private/kernel/disk_device_manager/ddm_userland_interface.h
+++ b/headers/private/kernel/disk_device_manager/ddm_userland_interface.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2003-2008, Haiku Inc.
+ * Copyright 2003-2009, Haiku Inc.
  * Distributed under the terms of the MIT License.
  *
  * Authors:
@@ -90,6 +90,10 @@ status_t _user_delete_child_partition(partition_id partitionID,
 				int32* changeCounter, partition_id childID,
 				int32 childChangeCounter);
 
+// change notification
+status_t _user_start_watching_disks(uint32 eventMask, port_id port, int32 token);
+status_t _user_stop_watching_disks(port_id port, int32 token);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/headers/private/system/syscalls.h b/headers/private/system/syscalls.h
index 4944b9eaab..e9f0cddce7 100644
--- a/headers/private/system/syscalls.h
+++ b/headers/private/system/syscalls.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2004-2008, Haiku Inc. All rights reserved.
+ * Copyright 2004-2009, Haiku Inc. All rights reserved.
  * Distributed under the terms of the MIT License.
  */
 #ifndef _SYSTEM_SYSCALLS_H
@@ -512,15 +512,10 @@ extern status_t		_kern_delete_child_partition(partition_id partitionID,
 						int32* changeCounter, partition_id childID,
 						int32 childChangeCounter);
 
-#if 0
-
-// watching
-status_t start_disk_device_watching(port_id, int32 token, uint32 flags);
-status_t start_disk_device_job_watching(disk_job_id job, port_id, int32 token,
-										uint32 flags);
-status_t stop_disk_device_watching(port_id, int32 token);
-
-#endif	// 0
+// disk change notification
+extern status_t		_kern_start_watching_disks(uint32 eventMask, port_id port,
+						int32 token);
+extern status_t		_kern_stop_watching_disks(port_id port, int32 token);
 
 
 // The end mark for gensyscallinfos.
diff --git a/src/kits/storage/disk_device/DiskDeviceRoster.cpp b/src/kits/storage/disk_device/DiskDeviceRoster.cpp
index 5fa873bb2c..c7b219fe70 100644
--- a/src/kits/storage/disk_device/DiskDeviceRoster.cpp
+++ b/src/kits/storage/disk_device/DiskDeviceRoster.cpp
@@ -22,6 +22,8 @@
 #include <Path.h>
 #include <Volume.h>
 
+#include <MessengerPrivate.h>
+
 #include <syscalls.h>
 #include <ddm_userland_interface_defs.h>
 
@@ -511,8 +513,14 @@ BDiskDeviceRoster::GetFileDeviceForPath(const char* filename,
 status_t
 BDiskDeviceRoster::StartWatching(BMessenger target, uint32 eventMask)
 {
-	// not implemented
-	return B_ERROR;
+	if (eventMask == 0)
+		return B_BAD_VALUE;
+
+	BMessenger::Private messengerPrivate(target);
+	port_id port = messengerPrivate.Port();
+	int32 token = messengerPrivate.Token();
+
+	return _kern_start_watching_disks(eventMask, port, token);
 }
 
 
@@ -525,8 +533,11 @@ BDiskDeviceRoster::StartWatching(BMessenger target, uint32 eventMask)
 status_t
 BDiskDeviceRoster::StopWatching(BMessenger target)
 {
-	// not implemented
-	return B_ERROR;
+	BMessenger::Private messengerPrivate(target);
+	port_id port = messengerPrivate.Port();
+	int32 token = messengerPrivate.Token();
+
+	return _kern_stop_watching_disks(port, token);
 }
 
 #if 0
diff --git a/src/system/kernel/disk_device_manager/KDiskDeviceManager.cpp b/src/system/kernel/disk_device_manager/KDiskDeviceManager.cpp
index 10c0ae6504..ed113a0a76 100644
--- a/src/system/kernel/disk_device_manager/KDiskDeviceManager.cpp
+++ b/src/system/kernel/disk_device_manager/KDiskDeviceManager.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright 2004-2008, Haiku, Inc. All rights reserved.
+ * Copyright 2004-2009, Haiku, Inc. All rights reserved.
  * Copyright 2003-2004, Ingo Weinhold, bonefish@cs.tu-berlin.de. All rights reserved.
  *
  * Distributed under the terms of the MIT License.
@@ -20,6 +20,7 @@
 #include <VectorMap.h>
 #include <VectorSet.h>
 
+#include <DiskDeviceRoster.h>
 #include <KernelExport.h>
 #include <NodeMonitor.h>
 
@@ -183,19 +184,42 @@ private:
 };
 
 
+class KDiskDeviceManager::DiskNotifications
+	: public DefaultUserNotificationService {
+public:
+	DiskNotifications()
+		: DefaultUserNotificationService("disk devices")
+	{
+	}
+
+	virtual ~DiskNotifications()
+	{
+	}
+
+protected:
+	status_t _ToFlags(const KMessage& eventSpecifier, uint32& flags)
+	{
+		flags = eventSpecifier.GetInt32("flags", 0);
+		return B_OK;
+	}
+};
+
+
 //	#pragma mark -
 
 
 KDiskDeviceManager::KDiskDeviceManager()
-	: fLock("disk device manager"),
-	  fDevices(new(nothrow) DeviceMap),
-	  fPartitions(new(nothrow) PartitionMap),
-	  fDiskSystems(new(nothrow) DiskSystemMap),
-	  fObsoletePartitions(new(nothrow) PartitionSet),
-	  fMediaChecker(-1),
-	  fTerminating(false),
-	  fDiskSystemWatcher(NULL),
-	  fDeviceWatcher(new(nothrow) DeviceWatcher(this))
+	:
+	fLock("disk device manager"),
+	fDevices(new(nothrow) DeviceMap),
+	fPartitions(new(nothrow) PartitionMap),
+	fDiskSystems(new(nothrow) DiskSystemMap),
+	fObsoletePartitions(new(nothrow) PartitionSet),
+	fMediaChecker(-1),
+	fTerminating(false),
+	fDiskSystemWatcher(NULL),
+	fDeviceWatcher(new(nothrow) DeviceWatcher(this)),
+	fNotifications(new(nothrow) DiskNotifications)
 {
 	if (InitCheck() != B_OK)
 		return;
@@ -267,7 +291,8 @@ KDiskDeviceManager::~KDiskDeviceManager()
 status_t
 KDiskDeviceManager::InitCheck() const
 {
-	if (!fPartitions || !fDevices || !fDiskSystems || !fObsoletePartitions)
+	if (fPartitions == NULL || fDevices == NULL || fDiskSystems == NULL
+		|| fObsoletePartitions == NULL || fNotifications == NULL)
 		return B_NO_MEMORY;
 
 	return fLock.Sem() >= 0 ? B_OK : fLock.Sem();
@@ -323,6 +348,20 @@ KDiskDeviceManager::Unlock()
 }
 
 
+DefaultUserNotificationService&
+KDiskDeviceManager::Notifications()
+{
+	return *fNotifications;
+}
+
+
+void
+KDiskDeviceManager::Notify(const KMessage& event, uint32 eventMask)
+{
+	fNotifications->Notify(event, eventMask);
+}
+
+
 KDiskDevice*
 KDiskDeviceManager::FindDevice(const char* path)
 {
@@ -637,6 +676,9 @@ KDiskDeviceManager::CreateDevice(const char* path, bool* newlyCreated)
 			_ScanPartition(device, false);
 			device->UnmarkBusy(true);
 
+			_NotifyDeviceEvent(device, B_DEVICE_ADDED,
+				B_DEVICE_REQUEST_DEVICE_LIST);
+
 			if (newlyCreated)
 				*newlyCreated = true;
 
@@ -709,6 +751,9 @@ KDiskDeviceManager::CreateFileDevice(const char* filePath, bool* newlyCreated)
 			_ScanPartition(device, false);
 			device->UnmarkBusy(true);
 
+			_NotifyDeviceEvent(device, B_DEVICE_ADDED,
+				B_DEVICE_REQUEST_DEVICE_LIST);
+
 			if (newlyCreated)
 				*newlyCreated = true;
 
@@ -765,6 +810,7 @@ KDiskDeviceManager::NextDevice(int32* cookie)
 {
 	if (!cookie)
 		return NULL;
+
 	DeviceMap::Iterator it = fDevices->FindClose(*cookie, false);
 	if (it != fDevices->End()) {
 		KDiskDevice* device = it->Value();
@@ -787,7 +833,7 @@ KDiskDeviceManager::PartitionRemoved(KPartition* partition)
 {
 	if (partition && partition->PrepareForRemoval()
 		&& fPartitions->Remove(partition->ID())) {
-		// If adding the partition to the obsolete list fails (due to lack
+		// TODO: If adding the partition to the obsolete list fails (due to lack
 		// of memory), we can't do anything about it. We will leak memory then.
 		fObsoletePartitions->Insert(partition);
 		partition->MarkObsolete();
@@ -1091,8 +1137,14 @@ KDiskDeviceManager::_AddDevice(KDiskDevice* device)
 bool
 KDiskDeviceManager::_RemoveDevice(KDiskDevice* device)
 {
-	return (device && fDevices->Remove(device->ID())
-			&& PartitionRemoved(device));
+	if (device != NULL && fDevices->Remove(device->ID())
+		&& PartitionRemoved(device)) {
+		_NotifyDeviceEvent(device, B_DEVICE_REMOVED,
+			B_DEVICE_REQUEST_DEVICE_LIST);
+		return true;
+	}
+
+	return false;
 }
 
 
@@ -1433,6 +1485,8 @@ KDiskDeviceManager::_CheckMediaStatus()
 				dprintf("Media changed from %s\n", device->Path());
 				device->UpdateGeometry();
 				_ScanPartition(device, false);
+				_NotifyDeviceEvent(device, B_DEVICE_MEDIA_CHANGED,
+					B_DEVICE_REQUEST_DEVICE);
 			} else if (!device->HasMedia() && hadMedia) {
 				dprintf("Media removed from %s\n", device->Path());
 			}
@@ -1452,3 +1506,19 @@ KDiskDeviceManager::_CheckMediaStatusDaemon(void* self)
 {
 	return ((KDiskDeviceManager*)self)->_CheckMediaStatus();
 }
+
+
+void
+KDiskDeviceManager::_NotifyDeviceEvent(KDiskDevice* device, int32 event,
+	uint32 mask)
+{
+	char messageBuffer[512];
+	KMessage message;
+	message.SetTo(messageBuffer, sizeof(messageBuffer), B_DEVICE_UPDATE);
+	message.AddInt32("event", event);
+	message.AddInt32("id", device->ID());
+	message.AddString("device", device->Path());
+
+	fNotifications->Notify(message, mask);
+}
+
diff --git a/src/system/kernel/disk_device_manager/ddm_userland_interface.cpp b/src/system/kernel/disk_device_manager/ddm_userland_interface.cpp
index 965336eb32..60410dea19 100644
--- a/src/system/kernel/disk_device_manager/ddm_userland_interface.cpp
+++ b/src/system/kernel/disk_device_manager/ddm_userland_interface.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright 2003-2008, Haiku, Inc. All Rights Reserved.
+ * Copyright 2003-2009, Haiku, Inc. All Rights Reserved.
  * Distributed under the terms of the MIT License.
  *
  * Authors:
@@ -40,7 +40,6 @@ using namespace BPrivate::DiskDevice;
 // TODO: Add user address checks and check return values of user_memcpy()!
 
 
-// ddm_strlcpy
 /*! \brief Wrapper around user_strlcpy() that returns a status_t
 	indicating appropriate success or failure.
 
@@ -61,7 +60,6 @@ ddm_strlcpy(char *to, const char *from, size_t size,
 }
 
 
-// copy_from_user_value
 template<typename Type>
 static inline status_t
 copy_from_user_value(Type& value, const Type* userValue)
@@ -76,7 +74,6 @@ copy_from_user_value(Type& value, const Type* userValue)
 }
 
 
-// copy_to_user_value
 template<typename Type>
 static inline status_t
 copy_to_user_value(Type* userValue, const Type& value)
@@ -91,7 +88,6 @@ copy_to_user_value(Type* userValue, const Type& value)
 }
 
 
-// UserStringParameter
 template<bool kAllowsNull>
 struct UserStringParameter {
 	char*	value;
@@ -144,7 +140,6 @@ struct UserStringParameter {
 };
 
 
-// UserMemoryParameter
 template<typename Type, bool kAllowsNull>
 struct UserMemoryParameter {
 	Type*	value;
@@ -190,7 +185,6 @@ struct UserMemoryParameter {
 
 
 #if 0
-// move_descendants
 static void
 move_descendants(KPartition *partition, off_t moveBy)
 {
@@ -203,7 +197,6 @@ move_descendants(KPartition *partition, off_t moveBy)
 }
 
 
-// move_descendants_contents
 static status_t
 move_descendants_contents(KPartition *partition)
 {
@@ -228,7 +221,6 @@ move_descendants_contents(KPartition *partition)
 #endif // 0
 
 
-// _user_get_next_disk_device_id
 partition_id
 _user_get_next_disk_device_id(int32 *_cookie, size_t *neededSize)
 {
@@ -262,7 +254,6 @@ _user_get_next_disk_device_id(int32 *_cookie, size_t *neededSize)
 }
 
 
-// _user_find_disk_device
 partition_id
 _user_find_disk_device(const char *_filename, size_t *neededSize)
 {
@@ -293,7 +284,6 @@ _user_find_disk_device(const char *_filename, size_t *neededSize)
 }
 
 
-// _user_find_partition
 partition_id
 _user_find_partition(const char *_filename, size_t *neededSize)
 {
@@ -362,7 +352,6 @@ _user_find_file_disk_device(const char *_filename, size_t *neededSize)
 }
 
 
-// _user_get_disk_device_data
 /*!	\brief Writes data describing the disk device identified by ID and all
 		   its partitions into the supplied buffer.
 
@@ -454,7 +443,6 @@ _user_get_disk_device_data(partition_id id, bool deviceOnly,
 }
 
 
-// _user_register_file_device
 partition_id
 _user_register_file_device(const char *_filename)
 {
@@ -475,7 +463,6 @@ _user_register_file_device(const char *_filename)
 }
 
 
-// _user_unregister_file_device
 status_t
 _user_unregister_file_device(partition_id deviceID, const char *_filename)
 {
@@ -520,7 +507,6 @@ _user_get_file_disk_device_path(partition_id id, char* buffer,
 }
 
 
-// _user_get_disk_system_info
 status_t
 _user_get_disk_system_info(disk_system_id id, user_disk_system_info *_info)
 {
@@ -539,7 +525,6 @@ _user_get_disk_system_info(disk_system_id id, user_disk_system_info *_info)
 }
 
 
-// _user_get_next_disk_system_info
 status_t
 _user_get_next_disk_system_info(int32 *_cookie, user_disk_system_info *_info)
 {
@@ -562,7 +547,6 @@ _user_get_next_disk_system_info(int32 *_cookie, user_disk_system_info *_info)
 }
 
 
-// _user_find_disk_system
 status_t
 _user_find_disk_system(const char *_name, user_disk_system_info *_info)
 {
@@ -585,7 +569,6 @@ _user_find_disk_system(const char *_name, user_disk_system_info *_info)
 }
 
 
-// _user_defragment_partition
 status_t
 _user_defragment_partition(partition_id partitionID, int32* _changeCounter)
 {
@@ -640,7 +623,6 @@ _user_defragment_partition(partition_id partitionID, int32* _changeCounter)
 }
 
 
-// _user_repair_partition
 status_t
 _user_repair_partition(partition_id partitionID, int32* _changeCounter,
 	bool checkOnly)
@@ -696,7 +678,6 @@ _user_repair_partition(partition_id partitionID, int32* _changeCounter,
 }
 
 
-// _user_resize_partition
 status_t
 _user_resize_partition(partition_id partitionID, int32* _changeCounter,
 	partition_id childID, int32* _childChangeCounter, off_t size,
@@ -792,7 +773,6 @@ _user_resize_partition(partition_id partitionID, int32* _changeCounter,
 }
 
 
-// _user_move_partition
 status_t
 _user_move_partition(partition_id partitionID, int32* changeCounter,
 	partition_id childID, int32* childChangeCounter, off_t newOffset,
@@ -834,7 +814,6 @@ return B_BAD_VALUE;
 }
 
 
-// _user_set_partition_name
 status_t
 _user_set_partition_name(partition_id partitionID, int32* _changeCounter,
 	partition_id childID, int32* _childChangeCounter, const char* _name)
@@ -915,7 +894,6 @@ _user_set_partition_name(partition_id partitionID, int32* _changeCounter,
 }
 
 
-// _user_set_partition_content_name
 status_t
 _user_set_partition_content_name(partition_id partitionID,
 	int32* _changeCounter, const char* _name)
@@ -975,7 +953,6 @@ _user_set_partition_content_name(partition_id partitionID,
 }
 
 
-// _user_set_partition_type
 status_t
 _user_set_partition_type(partition_id partitionID, int32* _changeCounter,
 	partition_id childID, int32* _childChangeCounter, const char* _type)
@@ -1056,7 +1033,6 @@ _user_set_partition_type(partition_id partitionID, int32* _changeCounter,
 }
 
 
-// _user_set_partition_parameters
 status_t
 _user_set_partition_parameters(partition_id partitionID, int32* _changeCounter,
 	partition_id childID, int32* _childChangeCounter, const char* _parameters,
@@ -1139,7 +1115,6 @@ _user_set_partition_parameters(partition_id partitionID, int32* _changeCounter,
 }
 
 
-// _user_set_partition_content_parameters
 status_t
 _user_set_partition_content_parameters(partition_id partitionID,
 	int32* _changeCounter, const char* _parameters, size_t parametersSize)
@@ -1201,7 +1176,6 @@ _user_set_partition_content_parameters(partition_id partitionID,
 }
 
 
-// _user_initialize_partition
 status_t
 _user_initialize_partition(partition_id partitionID, int32* _changeCounter,
 	const char* _diskSystemName, const char* _name, const char* _parameters,
@@ -1276,7 +1250,6 @@ _user_initialize_partition(partition_id partitionID, int32* _changeCounter,
 }
 
 
-// _user_uninitialize_partition
 status_t
 _user_uninitialize_partition(partition_id partitionID, int32* _changeCounter)
 {
@@ -1328,7 +1301,6 @@ _user_uninitialize_partition(partition_id partitionID, int32* _changeCounter)
 }
 
 
-// _user_create_child_partition
 status_t
 _user_create_child_partition(partition_id partitionID, int32* _changeCounter,
 	off_t offset, off_t size, const char* _type, const char* _name,
@@ -1404,7 +1376,6 @@ _user_create_child_partition(partition_id partitionID, int32* _changeCounter,
 }
 
 
-// _user_delete_child_partition
 status_t
 _user_delete_child_partition(partition_id partitionID, int32* _changeCounter,
 	partition_id childID, int32 childChangeCounter)
@@ -1473,3 +1444,20 @@ _user_delete_child_partition(partition_id partitionID, int32* _changeCounter,
 
 	return B_OK;
 }
+
+
+status_t
+_user_start_watching_disks(uint32 eventMask, port_id port, int32 token)
+{
+	KDiskDeviceManager* manager = KDiskDeviceManager::Default();
+	return manager->Notifications().UpdateUserListener(eventMask, port, token);
+}
+
+
+status_t
+_user_stop_watching_disks(port_id port, int32 token)
+{
+	KDiskDeviceManager* manager = KDiskDeviceManager::Default();
+	return manager->Notifications().RemoveUserListeners(port, token);
+}
+