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+Title: What would it cost to store all phone calls in Norway?
+Tags: english, personvern, surveillance
+Date: 2015-05-01 18:40
+
+<p>Many years ago, a friend of mine calculated how much it would cost
+to store the sound of all phone calls in Norway, and came up with the
+cost of around 20 million NOK for all the calls in a year.  I got
+curious and wondered what the same calculation would look like today.
+To do so one need an idea of how much data storage is needed for each
+minute of sound, how many minutes all the calls in Norway sums up to,
+and the cost of data storage.</p>
+
+<p>The 2005 numbers are from
+<ahref="http://www.digi.no/analyser/2005/10/04/vi-prater-stadig-mindre-i-roret">digi.no</a>,
+the 2012 numbers are from
+<ahref="http://www.nkom.no/aktuelt/nyheter/fortsatt-vekst-i-det-norske-ekommarkedet">a
+NKOM report</a>, and I got the 2013 numbers after asking NKOM via
+email.</p>
+
+<p>The amount of data storage per minute sound depend on the wanted
+quality, and for phone calls it is generally believed that 8 Kbit/s is
+enough.  Se for example a
+<ahref="http://www.cisco.com/c/en/us/support/docs/voice/voice-quality/7934-bwidth-consume.html#topic1">summary
+from Cisco</a> for some alternatives.  8 Kbit/s is 60 Kbytes/min, and
+this can be multiplied with the number of call minutes to get the
+storage requirements.</p>
+
+<p>Storage prices varies a lot, depending on speed, backup strategies,
+availability requirements etc.  But a simple way to calculate can be
+to use the price of a TiB-disk (around 1000 NOK) and double it to take
+space, power and redundancy.  It could be much higher with high speed
+and good redundancy requirements.</p>
+
+<p>But back to the question, What would it cost to store all phone
+calls in Norway?  Not much.  Here is a small table showing the
+estimated cost, which is within the budget constraint of most medium
+and large organisations:</p>
+
+<table>
+<tr><th>Year</th><th>Minutes of calls</th><th>Size</th><th>Price in NOK</th></tr>
+<tr><td>2005</td><td>24 000 000 000</td><td>1.3 PiB</td><td>3 mill</td></tr>
+<tr><td>2012</td><td>18 000 000 000</td><td>1.0 PiB</td><td>2.2 mill</td></tr>
+<tr><td>2013</td><td>17 000 000 000</td><td>950 TiB</td><td>2.1 mill</td></tr>
+</table>
+
+<p>This is the cost of buying the storage.  Maintenance need to be
+taken into account too, but I leave that as an exercise for the
+reader. :)</p>