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+++ b/buildframework/helium/doc/src/manual/sysdef3.rst	Tue Apr 27 08:33:08 2010 +0300
@@ -0,0 +1,81 @@
+System Definition v3 support
+============================
+
+Helium is now supporting System Definition v3 to achieve build. This document explains how to configure Helium and 
+ how input files are handled in the tool.
+ 
+
+How to configure the feature?
+-----------------------------
+
+In order to enable the support you first need to define the **new.schema** property to true. Then define a resource ant element to either 
+point to root definition file or package_definition.xml file.
+
+e.g:
+::
+   
+   <path id="system.definition.files">
+      <pathelement path="${build.drive}/sf_sytem_definition.xml" />
+      <fileset dir="${build.drive}" includes="root/*/*/package_definition.xml" />
+   </path>
+
+
+The previous example shows how you can configure your build to includes packages pointed by the sf_sytem_definition.xml, and a
+set of additional packages directly referenced (root system definition will then be generated automatically, see package_map.xml section).
+
+
+Package_map.xml
+---------------
+
+The package_map.xml provides mapping information between the package and it physical location under the build environment. The following
+example show how to write a package_map.xml file for a package that should be placed under sf/mw:
+
+::
+   
+   <?xml version="1.0"?>
+   <PackageMap root="sf" layer="mw" />
+   
+This information is also required to build from package_definition.xml file directly, so a valid root system model file can be generated
+automatically.
+
+
+The package_map.xml must be placed under the root directory of the package. **package_definition.xml** without package_map.xml are considered
+as invalid by the copying step and the automatic root system definition file generation. Only exception to that rule is for the virtual package
+which must be placed exactly two level under the root of the package.
+
+Example of package structure:
+::
+   
+   + <root>
+        + <layer>
+             + <package>
+                      - package_definition.xml
+                      - package_map.xml
+                      + component
+                              + nokia_<component>_metadata
+                                  - package_definition.xml  
+
+
+
+Canonical system definition generation workflow
+-----------------------------------------------
+The following diagram describes the workflow of the canonical System Definition file generation.
+
+.. image:: sysdefv3_workflow.png
+    :align: center
+
+The input of the workflow is the Ant resource identified by the **system.definition.files** id. Its content is then divided in two parts:
+ * package_definition.xml files
+ * other files considered as root system definition file.
+ 
+The package_definition.xml (and package_map.xml) will be used to generated a root system file, which will be used
+as any other root system definition file. The package_definition.xml will then be ignored from other operations.
+
+Then workflow converges into the following regular operations:
+ * joining each root system definition file into standalone model.
+ * merging each root files.
+ 
+The order of merging is defined by the order inside the resource, so to guaranty that order it is advised to use Ant path
+element rather than filesets. Also the generated model is always included at then end. 
+
+ 
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