and applications—all living in a browser window. Another solution would
bypass the Web browser, substituting
a more-capable software system that
runs as a separate application on the
client computer and communicates directly with servers in the cloud. This is
the idea behind AIR (formerly Apollo)
being tested by Adobe Systems. Open-Laszlo, an open-source project, works
in much the same way.
For those deploying software out in
the cloud, scalability is a major issue—
the need to marshal resources in such a
way that a program continues running
smoothly even as the number of users
grows. It’s not just that servers must respond to hundreds or thousands of requests per second; the system must also
coordinate information coming from
multiple sources, not all of which are
under the control of the same organization. The pattern of communication is
many-to-many, with each server talking
to multiple clients and each client invoking programs on multiple servers.
The other end of the cloud-comput-ing transaction—the browser-based
user interface—presents challenges
of another kind. The familiar window-and-menu layer of modern operating
systems has been fine-tuned over decades to meet user needs and expectations. Duplicating this functionality
inside a Web browser is a considerable
feat. Moreover, it has to be done in a
comparatively impoverished development environment. A programmer
creating a desktop application for Windows or one of the Unix variants can
choose from a broad array of programming languages, code libraries, and
application frameworks; major parts
of the user interface can be assembled
from pre-built components. The equivalent scaffolding for the Web computing platform is much more primitive.
A major challenge of moving applications to the cloud is the need to master multiple languages and operating
environments. In many cloud applications a back-end process relies on a relational database, so part of the code is
written in SQL or other query language.
On the client side, program logic is
embedded within HTML documents.
Standing between the database and the
client is a server application that might
be written in a scripting language (such
as PHP, Java, and Python). Information
exchanged between the various layers
is likely to be encoded in some variation of XML.
Even though the new model of remote computing seems to reverse the
1980s “liberation” movement that gave
individual users custody over programs
and data, the shift does not necessarily
restore control to managers in the corporate IT department.
To the extent that cloud computing succeeds, it represents an obvious
competitive challenge to vendors of
shrink-wrap software. Ironically, the
open-source movement could also
have a tough time adapting to the new
computing model. It’s one thing to create and distribute an open-source word
processor competing with Microsoft
Word; not so obvious is how a consortium of volunteers would create a Web
service to compete with Google Docs.
Finally, cloud computing raises
questions about privacy, security, and
reliability—a major subject of discussion at a workshop held last January
at the Center for Information Technology Policy at Princeton University.
Allowing a third-party service to take
custody of personal documents raises
awkward questions about control and
ownership: If you move to a competing
service provider, can you take your data
with you? Could you lose access to your
documents if you fail to pay your bill?
Do you have the power to expunge documents that are no longer wanted?
The issues of privacy and confidentiality are equally perplexing. In one
frequently cited scenario, a government agency presents a subpoena or
search warrant to the third party that
has possession of your data. If you had
retained physical custody, you might
still have been compelled to surrender
the information, but at least you would
have been able to decide for yourself
whether or not to contest the order.
The third-party service is presumably
less likely to go to court on your behalf.
In some circumstances you might not
even be informed that your documents
have been released. It seems likely that
much of the world’s digital information will be living in the clouds long before such questions are resolved.
Brian hayes writes about science and technology from
A Fly’s Life
A team of Swiss and U.S.
researchers have developed
an interactive virtual-reality
display system that enables
them to better understand
fruit flies’ behavior and
movement in response to
their visual environment,
New Scientist reports.
Led by Steven Fry of the
Institute of Neuroinformatics
in Zurich, the Swiss-U.S. team
built a wind tunnel in which
changing scenes or images are
projected onto its walls. A camera
tracks a fruit fly in 3D, making
the scenes or images move in
response to the animal’s
activity inside the wind tunnel.
Previous research had involved
tethered flies which, Fry
said, “is very unnatural and
it becomes very difficult to
interpret the data because
of the strong interference by
The team’s research, which
has implications for animal
behavior and biomimetic design
control, can be readily reproduced,
according to Fry. “Being based on
standard hardware and software
techniques, our methods
provide an affordable, easy to
replicate, and general solution
for a broad range of behavioral
applications in freely moving
animals,” he says.
The conductor paths in sensor
systems have traditionally
consisted of thin wires—until now.
Researchers at the Fraunhofer
Institute for Manufacturing
Engineering and Applied
Materials Research in Bremen,
Germany, have developed a new
technique that prints conductor
paths, using a contactless
aerosol ink with nano-sized silver
particles. In tests conducted with
the Institute for Microsensors,
Actuators and Systems at the
University of Bremen, the printed
conductor paths have proven
to be nearly 500 times thinner
than wire bonds, and the sensors
provide significantly more