diff -r c72c6eafadc6 -r f9fc2a3f8f70 common/build.xml
--- a/common/build.xml	Wed Jan 20 12:34:36 2010 +0000
+++ b/common/build.xml	Tue Jan 26 12:13:01 2010 +0000
@@ -18,8 +18,20 @@
         </then>
     </if>
     
+    <!-- If we've not has a physical drive specified, then we'd better be able to work one out... -->
+    <if>
+        <not><isset property="sf.spec.job.root.drive"/></not>
+        <then>
+            <exec executable="perl" outputproperty="sf.spec.job.root.drive" logerror="true" failonerror="true">
+                <arg value="${sf.common.config.dir}/tools/findPhysicalDrive.pl"/>
+            </exec>
+        </then>
+    </if>
+    
     <!-- Import common properties -->
     <import file="${sf.common.config.dir}/common_props.ant.xml" />
+
+    <property name="sf.spec.job.rootdir" value="${sf.spec.job.root.drive}/${sf.spec.job.root.path}"/>
     
     <!-- setup Helium internal properties from their equivalent in the project spec -->
     <property name="build.name" value="${sf.spec.job.name}"/>