Four years ago, I did a back of the envelope calculation on how much it would cost to store audio recordings of all the phone calls in Norway, and came up with NOK 2.1 million / EUR 250 000 for the year 2013. It is time to repeat the calculation using updated numbers. The calculation is based on how much data storage is needed for each minute of audio, how many minutes all the calls in Norway sums up to, multiplied by the cost of data storage.
The number of phone call minutes for 2018 was fetched from the NKOM statistics site, and for 2018, land line calls are listed as 434 238 000 minutes, while mobile phone calls are listed with 7 542 006 000 minutes. The total number of minutes is thus 7 976 244 000. For simplicity, I decided to ignore any advantages in audio compression the last four years, and continue to assume 60 Kbytes/min as the last time.
Storage prices still varies a lot, but as last time, I decide to take a reasonable big and cheap hard drive, and double its price to include the surrounding costs into account. A 10 TB disk cost less than 4500 NOK / 450 EUR these days, and doubling it give 9000 NOK per 10 TB.
So, with the parameters in place, lets update the old table estimating cost for calls in a given year:
| Year | Call minutes | Size | Price in NOK / EUR |
|---|---|---|---|
| 2005 | 24 000 000 000 | 1.3 PiB | 1 170 000 / 117 000 |
| 2012 | 18 000 000 000 | 1.0 PiB | 900 000 / 90 000 |
| 2013 | 17 000 000 000 | 950 TiB | 855 000 / 85 500 |
| 2018 | 7 976 244 000 | 445 TiB | 401 100 / 40 110 |
Both the cost of storage and the number of phone call minutes have dropped since the last time, bringing the cost down to a level where I guess even small organizations can afford to store the audio recording from every phone call taken in a year in Norway. Of course, this is just the cost of buying the storage equipment. Maintenance, need to be included as well, but the volume of a single year is about a single rack of hard drives, so it is not much more than I could fit in my own home. Wonder how much the electricity bill would raise if I had that kind of storage? I doubt it would be more than a few tens of thousand NOK per year.
