--- Modules/fcntlmodule.c	2011-11-02 15:56:19.000000000 +0000
+++ /Users/alex/Downloads/modified/Python-2.6.7/Modules/fcntlmodule.c	2011-11-02 16:00:31.000000000 +0000
@@ -534,6 +534,12 @@
 #ifdef F_FULLFSYNC
     if (ins(d, "F_FULLFSYNC", (long)F_FULLFSYNC)) return -1;
 #endif
+/* OS X defaults to caching files as 'inactive memory' for large files 
+ * this can result in significantly degraded system performance, F_NOCACHE
+ * allows control over whether data caching is enabled/disabled. */
+#ifdef F_NOCACHE
+    if (ins(d, "F_NOCACHE", (long)F_NOCACHE)) return -1;
+#endif
 
 /* For F_{GET|SET}FL */
 #ifdef FD_CLOEXEC