</div>
<div class="padding"></div>
+<div class="entry">
+ <div class="title">
+ <a href="../../../Using_bar_codes_at_a_computing_center.html">Using bar codes at a computing center</a>
+ </div>
+ <div class="date">
+ 2009-02-20 08:30
+ </div>
+
+ <div class="body">
+
+<p>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 "missing" computer.</p>
+
+<p>In the last issue of Linux Journal, I came across a project
+<a href="http://www.libdmtx.org/">libdmtx</a> to write and read bar
+code blocks as defined in the
+<a href="http://en.wikipedia.org/wiki/Data_Matrix">The Data Matrix
+Standard</a>. 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 <a href="http://www.terryburton.co.uk/barcodewriter/">a bar code
+writer written in postscript</a> capable of creating such bar codes,
+but this was the first time I found a tool to read these bar
+codes.</p>
+
+<p>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.</p>
+
+<p>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.</p>
+
+<p>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.</p>
+
+ </div>
+ <div class="tags">
+
+
+
+ Tags: <a href="../../../tags/english">english</a>, <a href="../../../tags/nuug">nuug</a>.
+
+ </div>
+</div>
+ <div class="padding"></div>
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