How much information is there in the world? University of Southern California researchers calculated that the world has access to enough data-storage capacity to hold 295 exabytes (295 followed by 20 zeros) of information.
reports aplenty about technology driving a data explosion. University of
Southern California researchers actually sat down and calculated that humans
can store, communicate and compute about 295 exabytes of information, or about
404 billion CDs.
In a study
published Feb. 10 in Science Express
, an electronic journal that provides
select Science articles ahead of print, researchers examined data from more
than 1,000 sources to calculate how much data-storage capacity exists. The
study, which looked at data from 1986 to 2007, did not try to calculate exactly
how much data actually existed.
"This is the
first study to quantify humankind's ability to handle information and how it
has changed in the last two decades," said lead author Martin Hilbert, a doctoral
candidate at the USC Annenberg School for Communication and Journalism.
his team calculated the figure by first estimating the amount of data held on
60 analog and digital technologies during the period from 1986 to 2007. They
considered everything from computer hard drives to obsolete floppy discs, and
X-ray film to microchips on credit cards, he said.
technological information-processing capacities are growing at exponential
rates," Hilbert said. General-purpose computing capacity is growing at about 58
percent per year, the study said. Telecommunications grew by 28 percent
annually, and storage capacity grew by 23 percent, according to the study.
what you can do with information is transmit it through space, and we call that
communication. You can transmit it through time; we call that storage. Or you
can transform it, manipulate it, change the meaning of it and we call that
computation," Hilbert said.
total, 295 exabytes refers to storage capacity in 2007, according to the
researchers. This is about 80 times more information per person than was ever
stored in the historic Library of Alexandria in Egypt, Hilbert told eWEEK. The
actual number for 2011 is likely to be much higher.
1.9 zettabytes of information through broadcast technology such as televisions
and GPS during that 21-year period, the study found. That's equivalent to every
person in the world receiving 174 newspapers every day or every television in
the world running for three hours a day, Hilbert said.
More than 65
exabytes of information was shared over two-communications technology, such as
cell phones and e-mail. Communications have increased by an average of 28 percent
every year since 1986. About 65 exabytes of information was shared in 2007, or
the equivalent of every single person sending out the contents of six
newspapers every day.
word-based chat, one would need to chat for two months and three weeks nonstop
to communicate the information that the average person telecommunicates through
multimedia content in one day only," Hilbert said.
All this feels
like unimaginable numbers. Just for comparison, an exabyte is equivalent to
1,000 petabytes, or a million terabytes. An exabyte has 20 zeros following the
number. A zettabyte is 1,000 exabytes.
performing calculations, the researcher discovered the digital age "began" in
2002, the first year there was more data stored on digital storage than on
analog, Hilbert said. About 75 percent of stored information was in an analog
format such as videocassettes and books in 2000. By 2007, the flip was nearly
complete, with 94 percent of information stored in digital form, Hilbert said.
storage types examined read like a list of forgotten devices. In 1986, "vinyl long-play
records" made up 14 percent of storage and audiocassettes made up 12 percent,
according to the study. Digital storage first became a significant factor in
2000, when it accounted for 25 percent of total storage capacity. The
proportion of paper-based storage such as books and newspapers declined, from a
mere 0.33 percent in 1986 to 0.007 percent in 2007. However, that didn't mean
information from paper sources declined, since in absolute terms, paper grew
from 8.7 to 19.4 optimally compressed petabytes, the study estimated.
of the Open University of Catalonia co-authored the study with Hilbert. Hilbert
said a copy of the Science article
is available on his