diff --git a/basis/windows/com/com.factor b/basis/windows/com/com.factor
index bdc055f787..b69189786f 100644
--- a/basis/windows/com/com.factor
+++ b/basis/windows/com/com.factor
@@ -1,6 +1,6 @@
 USING: alien alien.c-types alien.destructors windows.com.syntax
 windows.ole32 windows.types continuations kernel alien.syntax
-libc destructors accessors alien.data ;
+libc destructors accessors alien.data classes.struct windows.kernel32 ;
 IN: windows.com
 
 LIBRARY: ole32
@@ -31,6 +31,47 @@ COM-INTERFACE: IDropTarget IUnknown {00000122-0000-0000-C000-000000000046}
     HRESULT DragLeave ( )
     HRESULT Drop ( IDataObject* pDataObject, DWORD grfKeyState, POINTL pt, DWORD* pdwEffect ) ;
 
+COM-INTERFACE: ISequentialStream IUnknown {0C733A30-2A1C-11CE-ADE5-00AA0044773D}
+    HRESULT Read ( void* pv, ULONG cb, ULONG* pcbRead )
+    HRESULT Write ( void* pv, ULONG cb, ULONG* pcbWritten ) ;
+
+STRUCT: STATSTG
+    { pwcsName LPOLESTR }
+    { type DWORD }
+    { cbSize ULARGE_INTEGER }
+    { mtime FILETIME }
+    { ctime FILETIME }
+    { atime FILETIME }
+    { grfMode DWORD }
+    { grfLocksSupported DWORD }
+    { clsid CLSID }
+    { grfStateBits DWORD }
+    { reserved DWORD } ;
+
+CONSTANT: STGTY_STORAGE   1
+CONSTANT: STGTY_STREAM    2
+CONSTANT: STGTY_LOCKBYTES 3
+CONSTANT: STGTY_PROPERTY  4
+
+CONSTANT: STREAM_SEEK_SET 0
+CONSTANT: STREAM_SEEK_CUR 1
+CONSTANT: STREAM_SEEK_END 2
+
+CONSTANT: LOCK_WRITE     1
+CONSTANT: LOCK_EXCLUSIVE 2
+CONSTANT: LOCK_ONLYONCE  4
+
+COM-INTERFACE: IStream ISequentialStream {0000000C-0000-0000-C000-000000000046}
+    HRESULT Seek ( LARGE_INTEGER dlibMove, DWORD dwOrigin, ULARGE_INTEGER* plibNewPosition )
+    HRESULT SetSize ( ULARGE_INTEGER* libNewSize )
+    HRESULT CopyTo ( IStream* pstm, ULARGE_INTEGER* cb, ULARGE_INTEGER* pcbRead, ULARGE_INTEGER* pcbWritten )
+    HRESULT Commit ( DWORD grfCommitFlags )
+    HRESULT Revert ( )
+    HRESULT LockRegion ( ULARGE_INTEGER libOffset, ULARGE_INTEGER cb, DWORD dwLockType )
+    HRESULT UnlockRegion ( ULARGE_INTEGER libOffset, ULARGE_INTEGER cb, DWORD dwLockType )
+    HRESULT Stat ( STATSTG* pstatstg, DWORD grfStatFlag )
+    HRESULT Clone ( IStream** ppstm ) ;
+
 FUNCTION: HRESULT RegisterDragDrop ( HWND hWnd, IDropTarget* pDropTarget ) ;
 FUNCTION: HRESULT RevokeDragDrop ( HWND hWnd ) ;
 FUNCTION: void ReleaseStgMedium ( LPSTGMEDIUM pmedium ) ;
@@ -52,6 +93,4 @@ FUNCTION: void ReleaseStgMedium ( LPSTGMEDIUM pmedium ) ;
 
 DESTRUCTOR: com-release
 
-! XXX interfaces used by other libraries that should be fleshed out
-C-TYPE: IStream