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[homepage.git] / blog / archive / 2009 / 02 / 02.rss

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+       <item>
+               <title>Using bar codes at a computing center</title>
+               <link>../../../Using_bar_codes_at_a_computing_center.html</link>        
+               <guid isPermaLink="true">../../../Using_bar_codes_at_a_computing_center.html</guid>
+                <pubDate>Fri, 20 Feb 2009 08:30:00 +0100</pubDate>
+               <description>
+&lt;p&gt;At work with the University of Oslo, we have several hundred computers
+in our computing center.  This give us a challenge in tracking the
+location and cabling of the computers, when they are added, moved and
+removed.  Some times the location register is not updated when a
+computer is inserted or moved and we then have to search the room for
+the &quot;missing&quot; computer.&lt;/p&gt;
+
+&lt;p&gt;In the last issue of Linux Journal, I came across a project
+&lt;a href=&quot;http://www.libdmtx.org/&quot;&gt;libdmtx&lt;/a&gt; to write and read bar
+code blocks as defined in the
+&lt;a href=&quot;http://en.wikipedia.org/wiki/Data_Matrix&quot;&gt;The Data Matrix
+Standard&lt;/a&gt;.  This is bar codes that can be read with a normal
+digital camera, for example that on a cell phone, and several such bar
+codes can be read by libdmtx from one picture.  The bar code standard
+allow up to 2 KiB to be written in the tag.  There is another project
+with &lt;a href=&quot;http://www.terryburton.co.uk/barcodewriter/&quot;&gt;a bar code
+writer written in postscript&lt;/a&gt; capable of creating such bar codes,
+but this was the first time I found a tool to read these bar
+codes.&lt;/p&gt;
+
+&lt;p&gt;It occurred to me that this could be used to tag and track the
+machines in our computing center.  If both racks and computers are
+tagged this way, we can use a picture of the rack and all its
+computers to detect the rack location of any computer in that rack.
+If we do this regularly for the entire room, we will find all
+locations, and can detect movements and removals.&lt;/p&gt;
+
+&lt;p&gt;I decided to test if this would work in practice, and picked a
+random rack and tagged all the machines with their names.  Next, I
+took pictures with my digital camera, and gave the dmtxread program
+these JPEG pictures to see how many tags it could read.  This worked
+fairly well.  If the pictures was well focused and not taken from the
+side, all tags in the image could be read.  Because of limited space
+between the racks, I was unable to get a good picture of the entire
+rack, but could without problem read all tags from a picture covering
+about half the rack.  I had to limit the search time used by dmtxread
+to 60000 ms to make sure it terminated in a reasonable time frame.&lt;/p&gt;
+
+&lt;p&gt;My conclusion is that this could work, and we should probably look
+at adjusting our computer tagging procedures to use bar codes for
+easier automatic tracking of computers.&lt;/p&gt;
+</description>
+       </item>
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