diff --git a/lib/spack/spack/platforms/darwin.py b/lib/spack/spack/platforms/darwin.py
index 4c3d38851f8..7901f82d06a 100644
--- a/lib/spack/spack/platforms/darwin.py
+++ b/lib/spack/spack/platforms/darwin.py
@@ -12,7 +12,11 @@ def __init__(self):
         super(Darwin, self).__init__('darwin')
         self.add_target(self.default, Target(self.default))
         mac_os = MacOsx()
+        
         self.default_os = mac_os.name
+        self.front_os = mac_os.name
+        self.back_os =  mac_os.name 
+
         self.add_operating_system(mac_os.name, mac_os)
 
     @classmethod
diff --git a/lib/spack/spack/platforms/linux.py b/lib/spack/spack/platforms/linux.py
index 3243a1dcdf0..18050ac79e1 100644
--- a/lib/spack/spack/platforms/linux.py
+++ b/lib/spack/spack/platforms/linux.py
@@ -13,6 +13,8 @@ def __init__(self):
         self.add_target(self.default, Target(self.default))
         linux_dist = LinuxDistro()
         self.default_os = linux_dist.name
+        self.front_os = linux_dist.name
+        self.back_os = linux_dist.name
         self.add_operating_system(linux_dist.name, linux_dist)
 
     @classmethod