diff --git a/README.md b/README.md
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--- /dev/null
+++ b/README.md
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+The OpenXT synchronizers
+
+![Block diagram of the OpenXT Synchonizer](diagrams/Syncstruct.png)
+
+Synchronizer XT enables sysadmins and IT professionals to securely and
+easily manage a large number of XenClient laptops and the Windows VMs
+that run on them.
+
+This contains the client part of the OpenXT synchronizer. The code here (mainly 
+sync_client/client.py) is a python program that runs in a low privilege service VM,
+makes an HTTPS to a synchronizer web server which tells it what VMs it should be running.
+client.py then compares this to the current state of the machine, downloads disks, configures
+and starts VM as appropriate.
+
+Note that client.py is a short running process which maintains no state. It runs once
+to completion and then exits. Normally client.py is started by launcher.py which handles
+getting the configuring information for client.py and running it regularly, and handling exits.
+
+## Dependencies
+
+sync-client requires:
+
+* a synchronizer server to get target state and VHDs from (see https://github.com/openxt/sync-server/). In
+turn the synchronizer server will require:
+** sync-database, a schema and stored procedures
+** sync-cli, commnad line tools to access that database
+** sync-wui, an optional web user interface for administrators
+* icbinn (https://github.com/openxt/icbinn) to provide specific filesystem access to dom0 to write VHD files
+* Python 2, (http://python.org)
+* dbus-python (https://pypi.python.org/pypi/pydbus/0.2) 
+
+Normally sync-client is built as part of an OpenXT build via the recipe (OpenEmbedded makefile) at:
+
+  https://github.com/OpenXT/xenclient-oe/blob/master/recipes-openxt/xenclient/sync-client_git.bb
+
+## Getting help
+
+Start at:
+
+  http://www.openxt.org/
+
+for details of reaching the OpenXT community.
+
+
+## Authors
+
+This document was written by Dickon Reed, dickon@cantab.net, 20th
+February 2015. 
+
+The OpenXT synchronizer was written by a wider team, who may wish to add
+themselves to this README file.
+
diff --git a/diagrams/Syncstruct.dia b/diagrams/Syncstruct.dia
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+<tr><td></td><th>Date/Time</th><th>Dimensions</th><th>User</th><th>Comment</th></tr>
+<tr><td>current</td><td class='filehistory-selected' style='white-space: nowrap;'><a href="/images/1/1a/Syncstruct.dia">17:10, 11 April 2012</a></td><td> <span style="white-space: nowrap;">(4 KB)</span></td><td><a href="/index.php?title=User:Dickonr&amp;action=edit&amp;redlink=1" class="new mw-userlink" title="User:Dickonr (page does not exist)">Dickonr</a> <span style="white-space: nowrap;"> <span class="mw-usertoollinks">(<a href="/index.php?title=User_talk:Dickonr&amp;action=edit&amp;redlink=1" class="new" title="User talk:Dickonr (page does not exist)">Talk</a> | <a href="/index.php/Special:Contributions/Dickonr" title="Special:Contributions/Dickonr">contribs</a>)</span></span></td><td dir="ltr"></td></tr>
+<tr><td></td><td  style='white-space: nowrap;'><a href="/images/archive/1/1a/20120411171057%21Syncstruct.dia">14:26, 17 January 2012</a></td><td> <span style="white-space: nowrap;">(4 KB)</span></td><td><a href="/index.php?title=User:Apeace&amp;action=edit&amp;redlink=1" class="new mw-userlink" title="User:Apeace (page does not exist)">Apeace</a> <span style="white-space: nowrap;"> <span class="mw-usertoollinks">(<a href="/index.php?title=User_talk:Apeace&amp;action=edit&amp;redlink=1" class="new" title="User talk:Apeace (page does not exist)">Talk</a> | <a href="/index.php/Special:Contributions/Apeace" title="Special:Contributions/Apeace">contribs</a>)</span></span></td><td dir="ltr">Minor changes; change BED to Python.</td></tr>
+<tr><td></td><td  style='white-space: nowrap;'><a href="/images/archive/1/1a/20120117142602%21Syncstruct.dia">16:44, 11 January 2012</a></td><td> <span style="white-space: nowrap;">(4 KB)</span></td><td><a href="/index.php?title=User:Dickonr&amp;action=edit&amp;redlink=1" class="new mw-userlink" title="User:Dickonr (page does not exist)">Dickonr</a> <span style="white-space: nowrap;"> <span class="mw-usertoollinks">(<a href="/index.php?title=User_talk:Dickonr&amp;action=edit&amp;redlink=1" class="new" title="User talk:Dickonr (page does not exist)">Talk</a> | <a href="/index.php/Special:Contributions/Dickonr" title="Special:Contributions/Dickonr">contribs</a>)</span></span></td><td dir="ltr">change language for sync-client </td></tr>
+<tr><td></td><td  style='white-space: nowrap;'><a href="/images/archive/1/1a/20120111164404%21Syncstruct.dia">16:06, 10 January 2012</a></td><td> <span style="white-space: nowrap;">(4 KB)</span></td><td><a href="/index.php?title=User:Dickonr&amp;action=edit&amp;redlink=1" class="new mw-userlink" title="User:Dickonr (page does not exist)">Dickonr</a> <span style="white-space: nowrap;"> <span class="mw-usertoollinks">(<a href="/index.php?title=User_talk:Dickonr&amp;action=edit&amp;redlink=1" class="new" title="User talk:Dickonr (page does not exist)">Talk</a> | <a href="/index.php/Special:Contributions/Dickonr" title="Special:Contributions/Dickonr">contribs</a>)</span></span></td><td dir="ltr">relabel database </td></tr>
+<tr><td></td><td  style='white-space: nowrap;'><a href="/images/archive/1/1a/20120110160626%21Syncstruct.dia">14:34, 10 January 2012</a></td><td> <span style="white-space: nowrap;">(4 KB)</span></td><td><a href="/index.php?title=User:Dickonr&amp;action=edit&amp;redlink=1" class="new mw-userlink" title="User:Dickonr (page does not exist)">Dickonr</a> <span style="white-space: nowrap;"> <span class="mw-usertoollinks">(<a href="/index.php?title=User_talk:Dickonr&amp;action=edit&amp;redlink=1" class="new" title="User talk:Dickonr (page does not exist)">Talk</a> | <a href="/index.php/Special:Contributions/Dickonr" title="Special:Contributions/Dickonr">contribs</a>)</span></span></td><td dir="ltr"></td></tr>
+<tr><td></td><td  style='white-space: nowrap;'><a href="/images/archive/1/1a/20120110143401%21Syncstruct.dia">14:27, 10 January 2012</a></td><td> <span style="white-space: nowrap;">(4 KB)</span></td><td><a href="/index.php?title=User:Dickonr&amp;action=edit&amp;redlink=1" class="new mw-userlink" title="User:Dickonr (page does not exist)">Dickonr</a> <span style="white-space: nowrap;"> <span class="mw-usertoollinks">(<a href="/index.php?title=User_talk:Dickonr&amp;action=edit&amp;redlink=1" class="new" title="User talk:Dickonr (page does not exist)">Talk</a> | <a href="/index.php/Special:Contributions/Dickonr" title="Special:Contributions/Dickonr">contribs</a>)</span></span></td><td dir="ltr">dia source</td></tr>
+</table>
+
+</div>
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diff --git a/diagrams/Syncstruct.png b/diagrams/Syncstruct.png
new file mode 100644
index 0000000..e6b155d
Binary files /dev/null and b/diagrams/Syncstruct.png differ

	Date/Time	Dimensions	User	Comment
current	17:10, 11 April 2012	(4 KB)	Dickonr (Talk \| contribs)
	14:26, 17 January 2012	(4 KB)	Apeace (Talk \| contribs)	Minor changes; change BED to Python.
	16:44, 11 January 2012	(4 KB)	Dickonr (Talk \| contribs)	change language for sync-client
	16:06, 10 January 2012	(4 KB)	Dickonr (Talk \| contribs)	relabel database
	14:34, 10 January 2012	(4 KB)	Dickonr (Talk \| contribs)
	14:27, 10 January 2012	(4 KB)	Dickonr (Talk \| contribs)	dia source