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Scientists calculate total data stored to date: 295+ exabytes

USC report calculates amount of stored data grew by 23% a year between 1986 and 2007

February 14, 2011 06:00 AM ET

Computerworld - Humankind has stored more than 295 billion gigabytes (or 295 exabytes) of data since 1986, according to a new report based on research by scientists at the University of Southern California.

The scientists also concluded that 2002 should be considered the beginning of the digital age because it was the first year digital storage capacity overtook total analog capacity worldwide.

The study, published this week in the Science Express journal, stated that "if a single star is a bit of information, there's a galaxy of information for every person in the world. But it's still less than 1% of the information stored in all the DNA molecules of a human being."

The study tracked some 60 analog and digital technologies from 1986 to 2007, calculating the amount of data stored, communicated and computed. In 2007, 2.9 X 10^20 optimally compressed bytes were stored, almost X 10^21 bytes were communicated and 6.4 x 10^18 instructions per second were run on general purpose computers.

The study includes information gleaned from IT research firms, such as IDC.

For example, it cites IDC's estimate that in 2007 "all the empty or usable space on hard drives, tapes, CDs, DVDs, and memory (volatile and nonvolatile) in the market equaled 264 exabytes. However, using their own methodology, the USC scientists said they counted 276 "optimally compressed" exabytes on digital devices, which occupy 363 exabytes of digital hardware.

Before the digital revolution, the report said, the lions share of information was stored in analog videotapes, such as VHS cassettes and the like. In 1986, along with VHS tapes, vinyl LP records accounted for 14% of stored data, audio cassette tapes made up 12% and photography accounted for 8%.

It was not until 2000 that digital storage made a significant contribution, contributing 25% to the data storage total in 2000.

Beginning in 1986, the share of paper-based storage mediums began decreasing, from 33% that year to .007% in 2007.

In 2007, hard disk drives held 52% of all stored data, optical storage devices held 28%, and digital tape about 11%.

The majority of our technological memory has been in digital format since the early 2000s, with 94% of data stored in that format in 2007, the report indicated.

"We live in a world where economies, political freedom and cultural growth increasingly depend on our technological capabilities," said the report's lead author, Martin Hilbert, a Provost fellow at USC's Annenberg School for Communication & Journalism. "This is the first study to quantify humankind's ability to handle information and how it has changed in the last two decades."

Hilbert co-authored the study with Priscila Lopez of the Open University of Catalonia in Barcelona.



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