07-05-2013, 02:30 PM
Parasitic computing Abstract
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Abstract
Parasitic computing is often confused with a different type of shared computer services, normally called cluster computing. Clusters are groups of computers linked voluntarily to provide capacity well beyond the capability of any single computer. In the 20th century, an example of cluster computers was thousands of public and private computers linked to calculate signal data from a search for extraterrestrial intelligent life (SETI), or signals from other planets. A radio telescope scanned portions of the sky and collected radio signal data, and the clustered computers shared computing time to analyze the data and look for patterns.
Negative parasitic computing can occur if a computer is infected with a virus or software called a Trojan horse. Viruses can be downloaded from emails or infected web sites, and in some cases will allow the computer to become a parasite for a hacker, providing a computer that can infect others repeatedly. Infected computers can also send multiple requests to a legitimate web site and overwhelm its servers, a technique called a "denial of service attack" that can shut down web sites.
A Trojan horse is a software packet that is carried along with a legitimate message or web site, and is usually invisible to any casual computer user. This is why it was named for the mythical horse that hid soldiers used to surprise and defeat an enemy. When the Trojan horse installs itself in a new computer, it can use some of that computer's resources to send unauthorized emails called "spam", or provide stolen computing power to another person.