diff --git a/lib/spack/spack/architecture.py b/lib/spack/spack/architecture.py
index b1da8ae4a2..642a589f35 100644
--- a/lib/spack/spack/architecture.py
+++ b/lib/spack/spack/architecture.py
@@ -69,6 +69,25 @@ def compiler_strategy(self):
         else:
             return "PATH"
 
+    def to_dict(self):
+        print "to_dict"
+        d = {}
+        d['name'] = self.name
+        d['module_name'] = self.module_name
+        if self.architecture:
+            d['architecture'] = self.architecture
+        return d
+
+    @staticmethod
+    def from_dict(d):
+        print "from_dict"
+        target = Target.__new__(Target)
+        target.name = d['name']
+        target.module_name = d['module_name']
+        if 'architecture' in d:
+            target.architecture = d['architecture']
+        return target
+
     def __str__(self):
         return self.name
 
diff --git a/lib/spack/spack/spec.py b/lib/spack/spack/spec.py
index 3ba9c139a6..395faecde6 100644
--- a/lib/spack/spack/spec.py
+++ b/lib/spack/spack/spec.py
@@ -651,7 +651,7 @@ def to_node_dict(self):
         d = {
             'variants' : dict(
                 (name,v.enabled) for name, v in self.variants.items()),
-            'arch' : self.architecture,
+            'arch' : self.architecture.to_dict(),
             'dependencies' : dict((d, self.dependencies[d].dag_hash())
                                   for d in sorted(self.dependencies))
         }
@@ -680,7 +680,7 @@ def from_node_dict(node):
 
         spec = Spec(name)
         spec.versions = VersionList.from_dict(node)
-        spec.architecture = node['arch']
+        spec.architecture = spack.architecture.Target.from_dict(node['arch'])
 
         if node['compiler'] is None:
             spec.compiler = None