typedef struct _OBJECT_DIRECTORY
{
     POBJECT_DIRECTORY_ENTRY HashBuckets[37];
     EX_PUSH_LOCK Lock;
     PDEVICE_MAP DeviceMap;
     ULONG SessionId;
     PVOID NamespaceEntry;
     ULONG Flags;
} OBJECT_DIRECTORY, *POBJECT_DIRECTORY;

Windows Vista Kernel Structures