diff --git a/doc/devel/UML/eltorito.violet b/doc/devel/UML/eltorito.violet
index 4a5df24..b8a7d01 100644
--- a/doc/devel/UML/eltorito.violet
+++ b/doc/devel/UML/eltorito.violet
@@ -11,13 +11,18 @@
    </object> 
    <object class="java.awt.geom.Point2D$Double"> 
     <void method="setLocation"> 
-     <double>731.0</double> 
-     <double>193.0</double> 
+     <double>479.2699858975891</double> 
+     <double>226.94112549695433</double> 
     </void> 
    </object> 
   </void> 
   <void method="addNode"> 
    <object id="ClassNode1" class="com.horstmann.violet.ClassNode"> 
+    <void property="attributes"> 
+     <void property="text"> 
+      <string>block : uint32_t</string> 
+     </void> 
+    </void> 
     <void property="name"> 
      <void property="text"> 
       <string>ElToritoCatalog</string> 
@@ -26,8 +31,8 @@
    </object> 
    <object class="java.awt.geom.Point2D$Double"> 
     <void method="setLocation"> 
-     <double>474.0</double> 
-     <double>192.0</double> 
+     <double>472.58578643762684</double> 
+     <double>344.73506473629425</double> 
     </void> 
    </object> 
   </void> 
@@ -40,7 +45,8 @@ type : enum
 partition_type : enum
 load_seg : uint16
 load_size : uint16
-patch_isolinux : bool</string> 
+patch_isolinux : bool
+block: uint32_t</string> 
      </void> 
     </void> 
     <void property="name"> 
@@ -51,8 +57,8 @@ patch_isolinux : bool</string>
    </object> 
    <object class="java.awt.geom.Point2D$Double"> 
     <void method="setLocation"> 
-     <double>469.0</double> 
-     <double>329.0</double> 
+     <double>470.4142135623731</double> 
+     <double>487.3919189857866</double> 
     </void> 
    </object> 
   </void> 
@@ -67,8 +73,8 @@ images</string>
    </object> 
    <object class="java.awt.geom.Point2D$Double"> 
     <void method="setLocation"> 
-     <double>666.0</double> 
-     <double>301.0</double> 
+     <double>251.63542622468316</double> 
+     <double>429.69343417595167</double> 
     </void> 
    </object> 
   </void> 
@@ -87,8 +93,8 @@ images</string>
    </object> 
    <object class="java.awt.geom.Point2D$Double"> 
     <void method="setLocation"> 
-     <double>186.0</double> 
-     <double>186.0</double> 
+     <double>193.07106781186545</double> 
+     <double>334.49242404917493</double> 
     </void> 
    </object> 
   </void> 
@@ -135,64 +141,8 @@ node. This is needed when the image is written.</string>
    </object> 
    <object class="java.awt.geom.Point2D$Double"> 
     <void method="setLocation"> 
-     <double>347.0</double> 
-     <double>82.0</double> 
-    </void> 
-   </object> 
-  </void> 
-  <void method="addNode"> 
-   <object id="ClassNode5" class="com.horstmann.violet.ClassNode"> 
-    <void property="attributes"> 
-     <void property="text"> 
-      <string>block : uint32_t</string> 
-     </void> 
-    </void> 
-    <void property="name"> 
-     <void property="text"> 
-      <string>PreviousSessionImage</string> 
-     </void> 
-    </void> 
-   </object> 
-   <object class="java.awt.geom.Point2D$Double"> 
-    <void method="setLocation"> 
-     <double>539.0</double> 
-     <double>509.0</double> 
-    </void> 
-   </object> 
-  </void> 
-  <void method="addNode"> 
-   <object id="InterfaceNode0" class="com.horstmann.violet.InterfaceNode"> 
-    <void property="name"> 
-     <void property="text"> 
-      <string>«interface»
-DataSource</string> 
-     </void> 
-    </void> 
-   </object> 
-   <object class="java.awt.geom.Point2D$Double"> 
-    <void method="setLocation"> 
-     <double>746.5857864376269</double> 
-     <double>511.3380951166248</double> 
-    </void> 
-   </object> 
-  </void> 
-  <void method="addNode"> 
-   <object id="ClassNode6" class="com.horstmann.violet.ClassNode"> 
-    <void property="attributes"> 
-     <void property="text"> 
-      <string>block : uint32_t</string> 
-     </void> 
-    </void> 
-    <void property="name"> 
-     <void property="text"> 
-      <string>PreviousSessionCatalog</string> 
-     </void> 
-    </void> 
-   </object> 
-   <object class="java.awt.geom.Point2D$Double"> 
-    <void method="setLocation"> 
-     <double>287.0</double> 
-     <double>292.0</double> 
+     <double>57.81118318204312</double> 
+     <double>584.0458146424488</double> 
     </void> 
    </object> 
   </void> 
@@ -210,28 +160,8 @@ we can do may be wrong.</string>
    </object> 
    <object class="java.awt.geom.Point2D$Double"> 
     <void method="setLocation"> 
-     <double>644.3271028254218</double> 
-     <double>382.5643050695048</double> 
-    </void> 
-   </object> 
-  </void> 
-  <void method="addNode"> 
-   <object id="ClassNode7" class="com.horstmann.violet.ClassNode"> 
-    <void property="attributes"> 
-     <void property="text"> 
-      <string>path : char *</string> 
-     </void> 
-    </void> 
-    <void property="name"> 
-     <void property="text"> 
-      <string>LocalImage</string> 
-     </void> 
-    </void> 
-   </object> 
-   <object class="java.awt.geom.Point2D$Double"> 
-    <void method="setLocation"> 
-     <double>424.0</double> 
-     <double>511.0</double> 
+     <double>748.978906441031</double> 
+     <double>574.8973495522459</double> 
     </void> 
    </object> 
   </void> 
@@ -239,16 +169,137 @@ we can do may be wrong.</string>
    <object id="NoteNode3" class="com.horstmann.violet.NoteNode"> 
     <void property="text"> 
      <void property="text"> 
-      <string>Once we have support for all El-Torito features, namelly
-multiple boot images, this type is not needed, the info
-can be read and cached in a new catalog.</string> 
+      <string>The block in both Catalog and BootImage is needed
+for multissession images</string> 
      </void> 
     </void> 
    </object> 
    <object class="java.awt.geom.Point2D$Double"> 
     <void method="setLocation"> 
-     <double>52.325113060119634</double> 
-     <double>434.0605969759931</double> 
+     <double>629.3242465083424</double> 
+     <double>441.1316647878586</double> 
+    </void> 
+   </object> 
+  </void> 
+  <void method="addNode"> 
+   <object id="ClassNode5" class="com.horstmann.violet.ClassNode"> 
+    <void property="name"> 
+     <void property="text"> 
+      <string>File</string> 
+     </void> 
+    </void> 
+   </object> 
+   <object class="java.awt.geom.Point2D$Double"> 
+    <void method="setLocation"> 
+     <double>188.09040379562163</double> 
+     <double>172.5340546095176</double> 
+    </void> 
+   </object> 
+  </void> 
+  <void method="addNode"> 
+   <object id="ClassNode6" class="com.horstmann.violet.ClassNode"> 
+    <void property="name"> 
+     <void property="text"> 
+      <string>CatalogStream</string> 
+     </void> 
+    </void> 
+   </object> 
+   <object class="java.awt.geom.Point2D$Double"> 
+    <void method="setLocation"> 
+     <double>851.105100475371</double> 
+     <double>283.5127233261827</double> 
+    </void> 
+   </object> 
+  </void> 
+  <void method="addNode"> 
+   <object id="ClassNode7" class="com.horstmann.violet.ClassNode"> 
+    <void property="name"> 
+     <void property="text"> 
+      <string>FileStream</string> 
+     </void> 
+    </void> 
+   </object> 
+   <object class="java.awt.geom.Point2D$Double"> 
+    <void method="setLocation"> 
+     <double>743.4055403867466</double> 
+     <double>284.4253525880894</double> 
+    </void> 
+   </object> 
+  </void> 
+  <void method="addNode"> 
+   <object id="ClassNode8" class="com.horstmann.violet.ClassNode"> 
+    <void property="name"> 
+     <void property="text"> 
+      <string>TransformStream</string> 
+     </void> 
+    </void> 
+   </object> 
+   <object class="java.awt.geom.Point2D$Double"> 
+    <void method="setLocation"> 
+     <double>958.5987801403015</double> 
+     <double>279.8322618091961</double> 
+    </void> 
+   </object> 
+  </void> 
+  <void method="addNode"> 
+   <object id="InterfaceNode0" class="com.horstmann.violet.InterfaceNode"> 
+    <void property="name"> 
+     <void property="text"> 
+      <string>«interface»
+Stream</string> 
+     </void> 
+    </void> 
+   </object> 
+   <object class="java.awt.geom.Point2D$Double"> 
+    <void method="setLocation"> 
+     <double>847.6728065449973</double> 
+     <double>157.05765855361264</double> 
+    </void> 
+   </object> 
+  </void> 
+  <void method="addNode"> 
+   <object id="ClassNode9" class="com.horstmann.violet.ClassNode"> 
+    <void property="name"> 
+     <void property="text"> 
+      <string>IsoLinuxPatch</string> 
+     </void> 
+    </void> 
+   </object> 
+   <object class="java.awt.geom.Point2D$Double"> 
+    <void method="setLocation"> 
+     <double>968.73629022557</double> 
+     <double>384.6660889654818</double> 
+    </void> 
+   </object> 
+  </void> 
+  <void method="addNode"> 
+   <object id="NoteNode4" class="com.horstmann.violet.NoteNode"> 
+    <void property="text"> 
+     <void property="text"> 
+      <string>Generates the content of the catalog on-the-fly</string> 
+     </void> 
+    </void> 
+   </object> 
+   <object class="java.awt.geom.Point2D$Double"> 
+    <void method="setLocation"> 
+     <double>517.6021638285529</double> 
+     <double>107.48023074035522</double> 
+    </void> 
+   </object> 
+  </void> 
+  <void method="addNode"> 
+   <object id="NoteNode5" class="com.horstmann.violet.NoteNode"> 
+    <void property="text"> 
+     <void property="text"> 
+      <string>To apply the needed patch to isolinux
+images</string> 
+     </void> 
+    </void> 
+   </object> 
+   <object class="java.awt.geom.Point2D$Double"> 
+    <void method="setLocation"> 
+     <double>923.4814562296309</double> 
+     <double>509.1168824543143</double> 
     </void> 
    </object> 
   </void> 
@@ -275,18 +326,6 @@ can be read and cached in a new catalog.</string>
    <object idref="ClassNode1"/> 
    <object idref="NoteNode0"/> 
   </void> 
-  <void method="connect"> 
-   <object class="com.horstmann.violet.ClassRelationshipEdge"> 
-    <void property="bentStyle"> 
-     <object class="com.horstmann.violet.BentStyle" field="VHV"/> 
-    </void> 
-    <void property="endArrowHead"> 
-     <object class="com.horstmann.violet.ArrowHead" field="TRIANGLE"/> 
-    </void> 
-   </object> 
-   <object idref="ClassNode3"/> 
-   <object idref="ClassNode4"/> 
-  </void> 
   <void method="connect"> 
    <object class="com.horstmann.violet.ClassRelationshipEdge"> 
     <void property="bentStyle"> 
@@ -346,18 +385,108 @@ can be read and cached in a new catalog.</string>
      <object class="com.horstmann.violet.ArrowHead" field="TRIANGLE"/> 
     </void> 
    </object> 
+   <object idref="ClassNode3"/> 
    <object idref="ClassNode5"/> 
-   <object idref="ClassNode2"/> 
   </void> 
   <void method="connect"> 
    <object class="com.horstmann.violet.ClassRelationshipEdge"> 
+    <void property="bentStyle"> 
+     <object class="com.horstmann.violet.BentStyle" field="VHV"/> 
+    </void> 
     <void property="endArrowHead"> 
-     <object class="com.horstmann.violet.ArrowHead" field="V"/> 
+     <object class="com.horstmann.violet.ArrowHead" field="TRIANGLE"/> 
+    </void> 
+   </object> 
+   <object idref="ClassNode5"/> 
+   <object idref="ClassNode4"/> 
+  </void> 
+  <void method="connect"> 
+   <object class="com.horstmann.violet.ClassRelationshipEdge"> 
+    <void property="bentStyle"> 
+     <object class="com.horstmann.violet.BentStyle" field="VHV"/> 
+    </void> 
+    <void property="endArrowHead"> 
+     <object class="com.horstmann.violet.ArrowHead" field="TRIANGLE"/> 
     </void> 
     <void property="lineStyle"> 
      <object class="com.horstmann.violet.LineStyle" field="DOTTED"/> 
     </void> 
    </object> 
+   <object idref="ClassNode8"/> 
+   <object idref="InterfaceNode0"/> 
+  </void> 
+  <void method="connect"> 
+   <object class="com.horstmann.violet.ClassRelationshipEdge"> 
+    <void property="bentStyle"> 
+     <object class="com.horstmann.violet.BentStyle" field="VHV"/> 
+    </void> 
+    <void property="endArrowHead"> 
+     <object class="com.horstmann.violet.ArrowHead" field="TRIANGLE"/> 
+    </void> 
+    <void property="lineStyle"> 
+     <object class="com.horstmann.violet.LineStyle" field="DOTTED"/> 
+    </void> 
+   </object> 
+   <object idref="ClassNode7"/> 
+   <object idref="InterfaceNode0"/> 
+  </void> 
+  <void method="connect"> 
+   <object class="com.horstmann.violet.ClassRelationshipEdge"> 
+    <void property="bentStyle"> 
+     <object class="com.horstmann.violet.BentStyle" field="VH"/> 
+    </void> 
+    <void property="endArrowHead"> 
+     <object class="com.horstmann.violet.ArrowHead" field="V"/> 
+    </void> 
+    <void property="endLabel"> 
+     <string>1</string> 
+    </void> 
+    <void property="startArrowHead"> 
+     <object class="com.horstmann.violet.ArrowHead" field="BLACK_DIAMOND"/> 
+    </void> 
+   </object> 
+   <object idref="ClassNode8"/> 
+   <object idref="InterfaceNode0"/> 
+  </void> 
+  <void method="connect"> 
+   <object class="com.horstmann.violet.ClassRelationshipEdge"> 
+    <void property="bentStyle"> 
+     <object class="com.horstmann.violet.BentStyle" field="VHV"/> 
+    </void> 
+    <void property="endArrowHead"> 
+     <object class="com.horstmann.violet.ArrowHead" field="TRIANGLE"/> 
+    </void> 
+    <void property="lineStyle"> 
+     <object class="com.horstmann.violet.LineStyle" field="DOTTED"/> 
+    </void> 
+   </object> 
+   <object idref="ClassNode6"/> 
+   <object idref="InterfaceNode0"/> 
+  </void> 
+  <void method="connect"> 
+   <object class="com.horstmann.violet.NoteEdge"/> 
+   <object idref="ClassNode1"/> 
+   <object idref="NoteNode3"/> 
+  </void> 
+  <void method="connect"> 
+   <object class="com.horstmann.violet.NoteEdge"/> 
+   <object idref="ClassNode2"/> 
+   <object idref="NoteNode3"/> 
+  </void> 
+  <void method="connect"> 
+   <object class="com.horstmann.violet.NoteEdge"/> 
+   <object idref="ClassNode2"/> 
+   <object idref="NoteNode2"/> 
+  </void> 
+  <void method="connect"> 
+   <object class="com.horstmann.violet.ClassRelationshipEdge"> 
+    <void property="bentStyle"> 
+     <object class="com.horstmann.violet.BentStyle" field="HVH"/> 
+    </void> 
+    <void property="endArrowHead"> 
+     <object class="com.horstmann.violet.ArrowHead" field="V"/> 
+    </void> 
+   </object> 
    <object idref="ClassNode5"/> 
    <object idref="InterfaceNode0"/> 
   </void> 
@@ -370,30 +499,54 @@ can be read and cached in a new catalog.</string>
      <object class="com.horstmann.violet.ArrowHead" field="TRIANGLE"/> 
     </void> 
    </object> 
+   <object idref="ClassNode9"/> 
+   <object idref="ClassNode8"/> 
+  </void> 
+  <void method="connect"> 
+   <object class="com.horstmann.violet.ClassRelationshipEdge"> 
+    <void property="endArrowHead"> 
+     <object class="com.horstmann.violet.ArrowHead" field="V"/> 
+    </void> 
+   </object> 
+   <object idref="ClassNode1"/> 
+   <object idref="InterfaceNode0"/> 
+  </void> 
+  <void method="connect"> 
+   <object class="com.horstmann.violet.ClassRelationshipEdge"> 
+    <void property="bentStyle"> 
+     <object class="com.horstmann.violet.BentStyle" field="HVH"/> 
+    </void> 
+    <void property="endArrowHead"> 
+     <object class="com.horstmann.violet.ArrowHead" field="V"/> 
+    </void> 
+   </object> 
+   <object idref="ClassNode2"/> 
+   <object idref="InterfaceNode0"/> 
+  </void> 
+  <void method="connect"> 
+   <object class="com.horstmann.violet.ClassRelationshipEdge"> 
+    <void property="bentStyle"> 
+     <object class="com.horstmann.violet.BentStyle" field="VH"/> 
+    </void> 
+    <void property="endArrowHead"> 
+     <object class="com.horstmann.violet.ArrowHead" field="V"/> 
+    </void> 
+    <void property="lineStyle"> 
+     <object class="com.horstmann.violet.LineStyle" field="DOTTED"/> 
+    </void> 
+   </object> 
    <object idref="ClassNode6"/> 
    <object idref="ClassNode1"/> 
   </void> 
   <void method="connect"> 
    <object class="com.horstmann.violet.NoteEdge"/> 
-   <object idref="ClassNode5"/> 
-   <object idref="NoteNode2"/> 
-  </void> 
-  <void method="connect"> 
-   <object class="com.horstmann.violet.ClassRelationshipEdge"> 
-    <void property="bentStyle"> 
-     <object class="com.horstmann.violet.BentStyle" field="VHV"/> 
-    </void> 
-    <void property="endArrowHead"> 
-     <object class="com.horstmann.violet.ArrowHead" field="TRIANGLE"/> 
-    </void> 
-   </object> 
-   <object idref="ClassNode7"/> 
-   <object idref="ClassNode2"/> 
+   <object idref="ClassNode6"/> 
+   <object idref="NoteNode4"/> 
   </void> 
   <void method="connect"> 
    <object class="com.horstmann.violet.NoteEdge"/> 
-   <object idref="ClassNode6"/> 
-   <object idref="NoteNode3"/> 
+   <object idref="ClassNode9"/> 
+   <object idref="NoteNode5"/> 
   </void> 
  </object> 
 </java> 
diff --git a/doc/devel/UML/eltorito.violet.png b/doc/devel/UML/eltorito.violet.png
index 07fd2b9..adc195c 100644
Binary files a/doc/devel/UML/eltorito.violet.png and b/doc/devel/UML/eltorito.violet.png differ