computation is shifting again, with functions migrating outward to distant data centers reached through the Internet. The new regime is not quite a return to the hub-and-spoke topology of time-sharing systems, if only because there is no hub. A client computer on the Internet can communicate with many servers at the same time, some of which may also be exchanging information among themselves. However, even if we are not returning to the architecture of time-sharing systems, the sudden stylishness of the cloud paradigm marks the reversal of a long-standing trend. Where end users and corporate IT managers once squabbled over possession of computing resources, both sides are now willing to surrender a large measure of control to third-party service providers. What brought about this change in attitude?

For the individual, total control comes at a price. Software must be installed and configured, then updated with each new release. The computational infrastructure of operating systems and low-level utilities must be maintained. Every update to the operating system sets off a cascade of subsequent revisions to other programs. Outsourcing computation to an Internet service eliminates nearly all these concerns. Cloud computing also offers end users advantages in terms of mobility and collaboration.

For software vendors who have shifted their operations into the cloud, the incentives are similar to those motivating end users. Software sold or licensed as a product to be installed on the user’s hardware must be able to cope with a baffling variety of operating environments. In contrast, software offered as an Internet-based service can be developed, tested, and run on a comput-

for most applications,
the entire user
interface resides
inside a single window
in a Web browser.

ing platform of the vendor’s choosing. Updates and bug fixes are deployed in minutes. (But the challenges of diversity don’t entirely disappear; the server-side software must be able to interact with a variety of clients.)

Although the new model of Internet computing has neither hub nor spokes, it still has a core and a fringe. The aim is to concentrate computation and storage in the core, where high-performance machines are linked by high-bandwidth connections, and all of these resources are carefully managed. At the fringe are the end users making the requests that initiate computations and who receive the results.

Although the future of cloud computing is less than clear, a few examples of present practice suggest likely directions:

Wordstar for the Web. The kinds of productivity applications that first attracted people to personal computers 30 years ago are now appearing as software services. The Google Docs programs are an example, including a word processor, a spreadsheet, and a tool for creating PowerPoint-like presentations. Another undertaking of this kind is Buzzword, a Web-based word processor acquired by Adobe Systems in 2007.

Another recent Adobe product is Pho-toshop Express, which has turned the well-known image-manipulation program into an online service.

Enterprise computing in the cloud. Software for major business applications (such as customer support, sales, and marketing) has generally been run on corporate servers, but several companies now provide it as an on-demand service. The first was Salesforce.com, founded in 1999, offering a suite of on-line programs for customer relationship management and other business-oriented tasks; the company’s slogan is “No software!”

Cloudy infrastructure. It’s all very well to outsource the chore of building and maintaining a data center, but someone must still supply that infrastructure. Amazon.com has moved into this niche of the Internet ecosystem. Amazon Web Services offers data storage priced by the gigabyte-month and computing capacity by the CPU-hour. Both kinds of resources expand and contract according to need. IBM has announced plans for the “Blue Cloud” infrastructure. And Google is testing the App Engine, which provides hosting on Google server farms and a software environment centered on the Python programming language and the Bigtable distributed storage system.

The cloud OS. For most cloud-com-puting applications, the entire user interface resides inside a single window in a Web browser. Several initiatives aim to provide a richer user experience for Internet applications. One approach is to exploit the cloud-com-puting paradigm to provide all the facilities of an operating system inside a browser. The eyeOS system, for example, reproduces the familiar desktop metaphor—with icons for files, folders,

Information Technology
Gartner’s Seven IT Grand Challenges

What are the most important IT challenges for the next 25 years? At the recent Gartner Emerging Trends Symposium/I Txpo, Gartner analysts identified seven IT grand challenges that, if met, will have profound economic, scientific and societal impacts. They are:

˲ Eliminate the need to manu-
ally recharge wireless devices
˲ Parallel programming applica-
tions that fully exploit multicore
processors
˲ Non-tactile, natural comput-
ing interfaces
˲ Automated computer-to-hu-
man speech translation

˲ Reliable, long-term digital storage

˲ Increase programmer productivity by 100 percent

˲ Identify the financial consequences of I T investments

“IT leaders should always be looking ahead for the emerging technologies that will have

a dramatic impact on their business, and information on many of these future innovations are already in some public domain,” says Gartner VP Ken McGee. To find such information, Gartner suggests examining relevant research papers, patents, and production prototypes.