Scientists calculate total data stored to date: 295+ exabytes

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 one per cent 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 per cent of stored data, audio cassette tapes made up 12 per cent and photography accounted for eight per cent.

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

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

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

The majority of our technological memory has been in digital format since the early 2000s, with 94 per cent 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.

Hilbert explained the study's findings in a short video found here .

The study found that data storage grew 23 per cent annually between 1986 and 2007.

General computing capacity from 1986 through 2007, grew at an annual rate of 58 per cent, the report said.

The world's capacity for bidirectional telecommunication through devices like cell phones, grew at 28 per cent per year. Overall, the world shared 65 exabytes of information through telecommunication devices.

At the same time, worldwide growth of unidirectional information through broadcast channels and the like, grew at only six per cent a year during the period. Even so, in 2007 humankind broadcast 1.9 zettabytes, or 1,900 exabytes, of information through technology such as televisions and GPS devices. "That's equivalent to every person in the world reading 174 newspapers every day," the study said.

The telecommunications business has been dominated by digital technologies since 1990, with 99.9 per cent of it in digital format in 2007.

Also in 2007, all the general-purpose computers in the world computed 6.4 x 10^18 instructions per second, the same general order of magnitude as the number of nerve impulses executed by a single human brain. "Doing these instructions by hand would take 2,200 times the period since the Big Bang," the study stated.

"These numbers are impressive , but still minuscule compared to the order of magnitude at which nature handles information," Hilbert said in a statement. "Compared to nature, we are but humble apprentices. However, while the natural world is mind-boggling in its size, it remains fairly constant. In contrast, the world's technological information-processing capacities are growing at exponential rates."

Lucas Mearian covers storage, disaster recovery and business continuity, financial services infrastructure and health care IT for Computerworld. Follow Lucas on Twitter at @lucasmearian , or subscribe to Lucas's RSS feed . His e-mail address is lmearian@computerworld.com .

Read more about storage in Computerworld's Storage Topic Center.

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