Distributed Net Applications Create Virtual Supercomputers

T he whole is greater than the sum of its parts. That, in some ways, explains the theory behind one of the most important new technological opportunities created by the Internet: distributed applications. In distributed Internet applications, functions are distributed online to dozens, thousands, or even millions of computers. These include distributed file-sharing applications, such as the controversial Napster, in which users share MP3 music files over the Internet, and Gnutella, an open-source application that lets users share all types of files. One increasingly important type of distributed application links a group of computers over the Internet to create a virtual supercomputer. The most computationally intensive long-term distributed Internet application on the planet, SETI@home, which analyzes signals in space looking for signs of intelligent life, runs on more than 2 million computers and processes an average aggregate of 12 teraflops, according to the project's chief scientist, Dan Wertheimer, an astronomer at the Uni-Distributed Internet applications are important because they utilize unused computer time to conduct the type of attacks on complex computing problems that used to require supercomputers, which are very expensive to use and inaccessible to most organizations. Running a complex computational problem costs about 1 percent as much to run on a distributed Internet application as on a supercomputer, said Scott Kurowski, founder and executive officer of Entropia, a provider of commercial and noncommercial distributed-Internet-computing services. The concept of distributed computing has been around for years but never took off because of past limitations in such areas as networking technologies. Now, however, more powerful processors , as well as faster communications technologies, are making it easier to link computers to perform complex distributed applications. And the increased demand for high-performance computing by a growing number of commercial and noncommer-cial organizations is driving demand for distributed applications. While the technology offers many benefits , proponents also face several important challenges and concerns. For example, researchers must develop ways to cope with such problems as digital Internet applications' high bandwidth consumption and the way Internet congestion influences the technology's effectiveness. In addition, security is a major concern for several reasons. For example, a network for rapidly distributing application code could also spread viruses and other malicious code. Nonetheless, proponents say, the technology has enormous promise. In fact, it has the potential to redefine the way we use the Internet, said Vern Paxson, a senior scientist at AT&T's Center for Internet …