diff -r 2c38c3c3b49a -r f3ab6c20c1e1 Lib/test/test_os_jy.py
--- a/Lib/test/test_os_jy.py	Thu Feb 19 16:41:54 2015 -0700
+++ b/Lib/test/test_os_jy.py	Fri Feb 20 15:04:39 2015 -0800
@@ -58,6 +58,21 @@
             else:
                 self.assertTrue(False)
 
+    def test_issue2068(self):
+        os.remove(test_support.TESTFN)
+        for i in range(2):
+            fd = os.open(test_support.TESTFN, os.O_RDWR | os.O_CREAT | os.O_APPEND)
+            try:
+                os.write(fd, bytes('one'))
+                os.write(fd, bytes('two'))
+                os.write(fd, bytes('three'))
+            finally:
+                fd.close()
+
+        with open(test_support.TESTFN, 'rb') as f:
+            content = f.read()
+        self.assertEqual(content, 2 * b'onetwothree')
+
 
 class OSDirTestCase(unittest.TestCase):
 
diff -r 2c38c3c3b49a -r f3ab6c20c1e1 src/org/python/core/io/FileIO.java
--- a/src/org/python/core/io/FileIO.java	Thu Feb 19 16:41:54 2015 -0700
+++ b/src/org/python/core/io/FileIO.java	Fri Feb 20 15:04:39 2015 -0800
@@ -306,13 +306,22 @@
         checkClosed();
         checkWritable();
         try {
-            return !emulateAppend ? fileChannel.write(buf) :
-                    fileChannel.write(buf, fileChannel.position());
+            return emulateAppend ? appendFromByteBuffer(buf)    // use this helper function to advance the file channel's position post-write
+                                    : fileChannel.write(buf);   // this does change the file channel's position
         } catch (IOException ioe) {
             throw Py.IOError(ioe);
         }
     }
 
+    private int appendFromByteBuffer(ByteBuffer buf) throws IOException {
+        int written = fileChannel.write(buf, fileChannel.position());   // this does not change the file channel's position!
+        if (written > 0) {
+            // we need to manually update the file channel's position post-write
+            fileChannel.position(fileChannel.position() + written);
+        }
+        return written;
+    }
+
     /**
      * Write bytes from each of the specified ByteBuffers via gather
      * i/o.
@@ -344,7 +353,8 @@
             if (!buf.hasRemaining()) {
                 continue;
             }
-            if ((bufCount = fileChannel.write(buf, fileChannel.position())) == 0) {
+            bufCount = appendFromByteBuffer(buf);
+            if (bufCount == 0) {
                 break;
             }
             count += bufCount;