diff --git a/cbits/posix.c b/cbits/posix.c
--- a/cbits/posix.c
+++ b/cbits/posix.c
@@ -22,7 +22,7 @@
 	access = O_RDONLY;
 	break;
     case 1:
-	access = O_RDWR;
+	access = O_RDWR|O_CREAT;
 	break;
     case 2:
 	access = O_RDONLY;
@@ -30,7 +30,7 @@
     default:
 	return NULL;
     }
-    handle = (void *)open(filepath,access|O_SHLOCK,0666);
+    handle = (void *)open(filepath,access,0666);
     if( handle==(void*)(-1) ) {
 	//fprintf(stderr,"open errno %d\n",errno);
         return NULL;
diff --git a/cbits/win32.c b/cbits/win32.c
--- a/cbits/win32.c
+++ b/cbits/win32.c
@@ -20,17 +20,21 @@
     */
     void *handle = NULL;
     DWORD dwDesiredAccess;
+    DWORD dwCreationDisposition;
     if( !filepath )
         return NULL;
     switch(mode) {
         case 0:
             dwDesiredAccess = GENERIC_READ;
+            dwCreationDisposition = OPEN_ALWAYS;
             break;
         case 1:
             dwDesiredAccess = GENERIC_WRITE|GENERIC_READ;
+            dwCreationDisposition = CREATE_ALWAYS;
             break;
         case 2:
             dwDesiredAccess = GENERIC_READ;
+            dwCreationDisposition = OPEN_ALWAYS;
             break;
         default:
             return NULL;
@@ -39,7 +43,7 @@
                          dwDesiredAccess,
                          FILE_SHARE_READ|FILE_SHARE_WRITE|FILE_SHARE_DELETE,
                          NULL,
-                         OPEN_EXISTING,
+                         dwCreationDisposition,
                          FILE_ATTRIBUTE_NORMAL,
                          NULL);
     if( handle==INVALID_HANDLE_VALUE )
diff --git a/mmap.cabal b/mmap.cabal
--- a/mmap.cabal
+++ b/mmap.cabal
@@ -1,5 +1,5 @@
 Name: mmap
-Version: 0.1
+Version: 0.2
 Stability: alpha
 License: BSD3
 License-File: LICENSE
diff --git a/tests/CpTest.hs b/tests/CpTest.hs
new file mode 100644
--- /dev/null
+++ b/tests/CpTest.hs
@@ -0,0 +1,103 @@
+
+
+module Main where
+
+import System.IO.MMap
+import qualified Data.ByteString.Char8 as BSC
+import qualified Data.ByteString.Lazy as BSL
+import Data.Word
+import Foreign.ForeignPtr
+import Foreign.Storable
+import Foreign.Ptr
+import System.Mem
+import Control.Concurrent
+import Control.Exception as E
+import Text.Printf
+import Control.Exception
+import System.CPUTime                                                          
+import System.Environment
+import System.IO
+import Data.ByteString.Internal
+
+
+time :: String -> IO t -> IO t
+time txt a = do
+    printf "%s: " txt
+    start <- getCPUTime
+    v <- a
+    v `seq` return ()
+    end   <- getCPUTime
+    let diff = (fromIntegral (end - start)) / (10^12)
+    printf "%0.3f sec\n" (diff :: Double)
+    return v
+
+
+main = do
+    [filename] <- getArgs
+
+    time "Prelude copy" $ do
+        hin <- openBinaryFile filename ReadMode
+        hout <- openBinaryFile (filename ++ ".prelude") WriteMode
+        c <- hGetContents hin
+        hPutStr hout c
+        hClose hin
+        hClose hout
+
+    time "ByteString copy" $ do
+        hin <- openBinaryFile filename ReadMode
+        hout <- openBinaryFile (filename ++ ".bytestring") WriteMode
+        c <- BSC.hGetContents hin
+        BSC.hPutStr hout c
+        hClose hin
+        hClose hout
+
+    time "ByteString.Lazy copy" $ do
+        hin <- openBinaryFile filename ReadMode
+        hout <- openBinaryFile (filename ++ ".bytestringlazy") WriteMode
+        c <- BSL.hGetContents hin
+        BSL.hPutStr hout c
+        hClose hin
+        hClose hout
+
+    time "MMap copy" $ do
+        (mmapin,fin1,size) <- mmapFilePtr filename ReadOnly Nothing
+        let newname = filename ++ ".mmap"
+        writeFile newname ""
+        (mmapout,fin2,size) <- mmapFilePtr newname ReadWrite (Just (0,size))
+        memcpy mmapout mmapin (fromIntegral size)
+        fin1
+        fin2
+
+    time "MMap copy lazy" $ do
+        chunksin <- mmapFileByteStringLazy filename Nothing
+        let newname = filename ++ ".mmaplazy"
+        hout <- openBinaryFile newname WriteMode
+        BSL.hPutStr hout chunksin
+
+        {-
+    BSC.writeFile "test.bin" content
+    bs <- mmapFileByteString "test.bin" Nothing
+    BSC.putStrLn bs
+    print (bs == content)
+    bs2 <- mmapFileByteString "test.bin" (Just (5,5))
+    print (bs2 == BSC.take 5 (BSC.drop 5 content))
+
+    -- create 5 gigabyte file
+    let l = 1024*1024*1024*5
+    (f,s) <- mmapFileForeignPtr "test.bin" ReadWrite (Just (l,5))
+    withForeignPtr f $ \f -> poke (castPtr f) (64::Word8)
+
+    E.catch (do
+              bs3 <- mmapFileByteString "test.bin" Nothing
+              print (fromIntegral l==BSC.length bs3 + 5 ))
+          (\e -> print True -- exception here is also ok
+          )
+    bs4 <- mmapFileByteStringLazy "test.bin" Nothing
+    print (BSL.fromChunks [content] == BSL.take (fromIntegral $ BSC.length content) bs4)
+    bs5 <- mmapFileByteStringLazy "test.bin" (Just (5,5))
+    print (BSC.take 5 (BSC.drop 5 content) == BSC.concat (BSL.toChunks bs5))
+
+    System.Mem.performGC
+    threadDelay 10000
+
+          -}