Configuration = set of program options. <br>
The program options of all components running to operate the telescope
can be set via <ul> 
<li> database</li>
<li> setup-file, e.g. program.rc</li>
<li> or command line option</li>
</ul>

A history of the configuration inserted into the database is kept.
Therefore, the configuration of the telescope at any time can be
viewed,  and configurations of different timestamps can be compared.
<br>
<br>

<u>The display</u>: 
<ul>
<li> additional (new) program options on the right side are displayed
in <font color='green'>green</font></li>
<li> additional (old) program options on the left side are displayed in
<font color='red'>red</font></li>
<li> program options where only the value has changed, are displayed in
<font color='blue'>blue</font></li>
<li> by default program, key, value and type are displayed. You can
display additional columns (for the two configurations independently).</li>
<li> for the time stamp, you can select between the 'pulldown' menus or
a 'text input' where you can enter the timestamp. 
<li> in case the timestamp is empty, the current configuration is
shown.</li>
<li> 'next/prev time stamp' and 'reset dates' directly issue the
display and comparison of the configurations. When you select a
timestamp by hand, you have to click 'show / compare'</li>
<li> a subset of program options can be view by specifying the program
and/or the key. </li>
</ul>
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