Autres/Rivendellaudio
1
0
Fork 0
mirror of https://github.com/ElvishArtisan/rivendell.git synced 2025-10-11 09:03:40 +02:00
Code Issues Projects Releases Wiki Activity

2021-10-28 Fred Gleason <fredg@paravelsystems.com>

Browse Source 
* Added a 'Daylight Saving Time' section to the 'Automating Tasks
	with RDCatch' chapter of the Operations Guide.

Signed-off-by: Fred Gleason <fredg@paravelsystems.com>
This commit is contained in:
Fred Gleason
2021-10-29 13:07:36 -04:00
parent 3a102c03e6
commit e7bc828a0a
2 changed files with 99 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

96
docs/opsguide/rdcatch.xml
View File

@@ -392,7 +392,103 @@
follow, but these are less important for understanding the
operation of RDCatch.
</para>
<sect3 xml:id="sect.rdcatch.the_event_list.daylight_saving_time_considerations">
<title>Daylight Saving Time Considerations</title>
<para>
Many governmental jurisdictions have promulgated regulations
dictating that local clocks be adjusted at certain times of
the year --e.g. during summertime or certain religious events.
Commonly known as &quot;Daylight Saving Time&quot;,
&quot;Summer Time&quot; or &quot;Ramadan Time&quot;,
special care must be taken
when configuring events that occur near or during a transition
from &quot;standard&quot; time to &quot;daylight saving time&quot;
and vice-versa. There are two basic types of such transitions; a
&quot;spring forward&quot; transition, during which the local clock
is advanced some period of time (typically an hour) and a
&quot;fall back&quot; transition, during which the local clock is
set back some period of time (again, typically an hour).
</para>
<sect4 xml:id="sect.rdcatch.the_event_list.daylight_saving_time_considerations.spring_forward_transitions">
<title>Spring Forward Transitions</title>
<para>
When &quot;springing forward&quot;, the local clock will simply
skip past certain time values. For example, imagine that we have
a transition where, at 02:00:00 exactly (2:00:00 AM), the clock
will be advanced 1 hour. A digital clock counting through this
transition would show values like:
</para>
<literallayout>
[...]
01:59:57
01:59:58
01:59:59
03:00:00
03:00:01
03:00:02
[...]
</literallayout>
<para>
In this example, the entire 2 AM hour simply
<emphasis>doesn't exist</emphasis>. Hence, any RDCatch events
that reference such events will <emphasis>not</emphasis> be
executed.
</para>
<warning>
This applies not only to configured &lt;start-time&gt; values,
but also to &lt;end-time&gt; ones as well.
If <emphasis>any</emphasis>
configured times in an event fall into a &quot;skipped&quot;
time period, then the entire event will be skipped.
</warning>
</sect4>
<sect4 xml:id="sect.rdcatch.the_event_list.daylight_saving_time_considerations.fall_back_transitions">
<title>Fall Back Transitions</title>
<para>
&quot;Fall-back&quot; transitions have the exact opposite behavior.
Specifically, the time period over which the transition occurs
is <emphasis>duplicated</emphasis>. For example, imagine
that we have a transition where, at 02:00:00 exactly (2:00:00 AM),
the clock will be set back 1 hour. A digital clock counting
through this transition would show values like:
</para>
<literallayout>
[...]
01:59:57
01:59:58
01:59:59
01:00:00
01:00:01
01:00:02
[...]
</literallayout>
<para>
The end of the <emphasis>second</emphasis> 1 AM hour then proceeds
normally:
</para>
<literallayout>
[...]
01:59:57
01:59:58
01:59:59
02:00:00
02:00:01
02:00:02
[...]
</literallayout>
<para>
When dealing with a transition of this sort, RDCatch will treat
times that occur within the transition as belonging to the
<emphasis>first pass</emphasis>; with the all times in the
<emphasis>second pass</emphasis> being ignored.
</para>
</sect4>
</sect3>
</sect2>
<sect2 xml:id="sect.rdcatch_the_button_area">
<title>The Button Area</title>
<para>