diff --git a/Lib/test/test_array.py b/Lib/test/test_array.py
index 5b6b9f2..ff9026a 100755
--- a/Lib/test/test_array.py
+++ b/Lib/test/test_array.py
@@ -964,20 +964,21 @@
     minitemsize = 8
 
     def test_alloc_overflow(self):
+        from sys import maxsize
         a = array.array('d', [-1]*65536)
         try:
-            a *= 65536
+            a *= maxsize//65536 + 1
         except MemoryError:
             pass
         else:
-            self.fail("a *= 2**16 didn't raise MemoryError")
+            self.fail("Array of size > maxsize created - MemoryError expected")
         b = array.array('d', [ 2.71828183, 3.14159265, -1])
         try:
-            b * 1431655766
+            b * (maxsize//3 + 1)
         except MemoryError:
             pass
         else:
-            self.fail("a * 1431655766 didn't raise MemoryError")
+            self.fail("Array of size > maxsize created - MemoryError expected")
 
 tests.append(DoubleTest)
 
diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py
index a7f2322..f26e7bb 100644
--- a/Lib/test/test_threading.py
+++ b/Lib/test/test_threading.py
@@ -397,6 +397,12 @@
         import os
         if not hasattr(os, 'fork'):
             return
+        # Skip platforms with known problems forking from a worker thread.
+        # See http://bugs.python.org/issue3863.
+        if sys.platform in ('freebsd4', 'freebsd5', 'freebsd6', 'os2emx'):
+            print >>sys.stderr, ('Skipping test_3_join_in_forked_from_thread'
+                                 ' due to known OS bugs on'), sys.platform
+            return
         script = """if 1:
             main_thread = threading.current_thread()
             def worker():