computerized documents from power blackouts, store them on Internet,
says UC Berkeley researcher
Catherine Zandonella, Media Relations
- For those who worry that California's rolling blackouts
will wipe out their bank statements and other computerized
records, a computer scientist at the University of California,
Berkeley, is designing a solution: A data storage system so
vast and powerful it will encompass the entire Earth.
is a data storage system tough enough to withstand a fire,
a hacker attack or even a botched electricity deregulation
attempt. By chopping data into encrypted pieces and storing
them on computers scattered throughout the Internet, OceanStore
expands storage capacity and makes data disaster-proof and
available any time, anywhere.
is to make data storage not only secure and available, but
downright impervious to disaster," said OceanStore's inventor,
John Kubiatowicz. The professor is part of UC Berkeley's proposed
Center for Information Technology Research in the Interest
of Society (CITRIS), a joint program with UC Davis and UC
Santa Cruz that will create innovations to improve people's
one chunk of data in Chicago and another in Taipei? Stowing
encrypted data throughout the Internet protects it from regional
events like power shortages, credit card number theft and
crippling "denial of service" attacks where Internet servers
are overwhelmed by bogus requests.
isn't all OceanStore has to offer. With more people creating
Web pages and snapping digital photographs, an Earth-sized
storage facility will be needed. A recent study by UC Berkeley
researchers found that the world's total yearly production
of print, film, optical and magnetic content requires roughly
1.5 billion gigabytes of storage, the textual content of billions
will be easy to access from almost anywhere, a crucial feature
as computing becomes increasingly mobile. Instead of carrying
around a heavy hard drive inside a laptop computer, one can
simply download data via wireless modem.
also will make possible so-called ubiquitous computing, where
every object has a computer in it, from athletic shoes to
toasters. Pervasive information flow is a goal of UC Berkeley's
Endeavor project, an initiative to enhance the interaction
between humans and technology.
will reduce the memory requirements of computerized devices
and provide a much-needed backup if the device fails. "If
you store your data in a ballpoint pen and then you lose the
pen, that is a disaster," said Kubiatowicz. OceanStore is
a key step in UC Berkeley's initiative to create Smart Dust,
miniature sensors the size of dust motes that can be used
to monitor bridges for seismic stability, or to sense and
respond to the heating needs of a building's occupants. These
tiny sensors will generate huge volumes of data that only
a widespread system like OceanStore could handle. OceanStore
and Smart Dust sensors are components of CITRIS, the UC Berkeley
the most important and unique feature of OceanStore is data
security. To ensure a document cannot be read by anyone but
its owner, OceanStore makes several copies of the data, encodes
them using a special coding mechanism, and then chops each
one into various-sized fragments.
track of these billions of bits of information, OceanStore
generates for each document a permanent, globally unique identification
(G.U.I.D.) tag. The document is then split into fragments,
which are sent out via the Internet to OceanStore servers.
OceanStore also creates a map showing the possible paths between
the interconnected Web servers.
a chopped-up 1989 tax return, for example, OceanStore sends
a team of messengers onto the Internet looking for its G.U.I.D.
As the messengers search, they leave behind trails of digital
breadcrumbs so that, the next time, the messenger can find
the data more quickly.
data from, say, China, could take a lot longer than getting
it from a desktop hard drive. OceanStore gets around this
by storing often-used documents on nearby servers. OceanStore
also can analyze patterns of usage so that the system can
fetch the data more quickly. Its software acts like a handyman,
constantly checking data segments and making minor adjustments
OceanStore world, no server can be trusted. Instead, the data
is distributed among multiple clusters of servers in a redundant
way so that, if one goes down, the data can be reassembled
using only one-fourth of the original fragments. "This storage
mechanism is very much like a hologram, where you only need
a certain subset of the data to recreate the entire image,"
all these bits of data floating around the Internet, Kubiatowicz
envisions a system not unlike our current telephone company
model. Each user would pay a monthly data storage fee to a
data service provider, such as an Internet service provider,
or I.S.P. The I.S.P. then arranges to store the user's data
on another I.S.P.'s Internet server for a small fee. The I.S.P.s
can then swap data amongst themselves, trading fees for using
each other's infrastructure and file servers.
for storage space growing and the reliability of local electricity
in question, technology companies are rushing to back OceanStore.
They include industry giants like I.B.M. Corp., Nortel Networks
Corp. and the data storage company EMC Corp. as well as federal
agencies like the National Science Foundation and the Defense
Advanced Research Projects Agency.