document: How closely can a personal computer clock track the UTC timescale via the Internet ? Nowadays many software packages allow you to keep the clock of your personal computer synchronized to time servers spread over the internet . We present how a didactic laboratory can evaluate , in a statistical sense , the minimum synch error of this process -LRB- the other extreme , the maximum , is guaranteed by the code itself -RRB- . The measurement set-up utilizes the global positioning system satellite constellation in ` common view ' between two similar timing stations : one acts as a time server for the other , so the final timing difference at the second station represents the total synch error through the internet . Data recorded over batches of 10000 samples show a typical RMS value of 35 ms. This measurement configuration allows students to obtain a much better understanding of the synch task and pushes them , at all times , to look for an experimental verification of data results , even when they come from the most sophisticated ` black boxes ' now readily available off the shelf
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extractive_keyphrases: personal computer clock utc timescale internet software packages time servers didactic laboratory statistical sense global positioning system satellite constellation final timing difference synch error black boxes