Distributed Denial Of Service (DDoS) Attack
A distributed denial-of-service (DDoS) attack is an attack in which multiple compromised computer systems attack a target, such as a server, website or other network resource, and cause a denial of service for users of the targeted resource. The flood of incoming messages, connection requests or malformed packets to the target system forces it to slow down or even crash and shut down, thereby denying service to legitimate users or systems.
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Web Application Firewall (WAF) Definition
Web Application Firewall (WAF) Definition
A Web application firewall (WAF) is a firewall that monitors, filters or blocks data packets as they travel to and from a Web application. A WAF can be either network-based, host-based or cloud-based and is often deployed through a proxy and placed in front of one or more Web applications. Running as a network appliance, server plug-in or cloud service, the WAF inspects each packet and uses a rule base to analyze Layer 7 web application logic and filt...
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Point-of-Presence (POP) Definition
Point-of-Presence (POP) Definition
On the Internet, a point-of-presence (POP) is an access point from one place to the rest of the Internet. (POP also stands for the e-mail Post Office Protocol; see POP3.) A POP necessarily has a unique Internet Protocol (IP) address. Your Internet service provider (ISP) or online service provider (such as AOL) has a point-of-presence on the Internet and probably more than one. The number of POPs that an ISP or OSP has is sometimes used as a measure of its si...
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ISP (Internet service provider) Definition
ISP (Internet service provider) Definition
An ISP (Internet service provider) is a company that provides individuals and other companies access to the Internet and other related services such as Web site building and virtual hosting. An ISP has the equipment and the telecommunication line access required to have a point-of-presence on the Internet for the geographic area served. The larger ISPs have their own high-speed leased lines so that they are less dependent on the telecommunication p...
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Laser Definition
Laser Definition
A laser is a coherent and focused beam of photons; coherent, in this context, means that it is all one wavelength, unlike ordinary light which showers on us in many wavelengths.
The acronym laser stands for "light amplification by stimulated emission of radiation." Lasers work as a result of resonant effects. The output of a laser is a coherent electromagnetic field. In a coherent beam of electromagnetic energy, all the waves have the same frequency and phase.
In a basi...
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Multisession CD Definition
Multisession CD Definition
A multisession CD is a recordable CD format (like a CD-R) that allows the recording of a compact disk to be conducted in more than one recording session. If there is free space left on the CD after the first session, additional data can be written to it at a later date. Each session has its own lead in, program area, and lead out. This takes up about 20 megabytes of space, and therefore, is less efficient than recording data all at once.
Multisession CDs ...
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Optical Media Definition
Optical Media Definition
Optical media - such as the compact disk (CD) - are storage media that hold content in digital form and that are written and read by a laser; these media include all the various CD and DVD variations, as well as optical jukeboxes and autochangers. Optical media have a number of advantages over magnetic media such as the floppy disk. Optical disk capacity ranges up to 6 gigabytes; that's 6 billion bytes compared to the 1.44 megabytes (MB) - 1,440,000 bytes - of the flo...
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Load Balancing Definition
Load Balancing Definition
What is Load Balancing? Load Balancing Definition Explained
What is load balancing? A load balancer is a piece of hardware (or virtual hardware) that acts like a reverse proxy to distribute network and/or application traffic across different servers. A load balancer is used to improve the concurrent user capacity and overall reliability of applications. A load balancer helps to improve these by distributing the workload across multiple servers, decreasing the ov...
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Pervasive Computing (ubiquitous computing)
Pervasive Computing (ubiquitous computing)
Pervasive computing (also called ubiquitous computing) is the growing trend towards embedding microprocessors in everyday objects so they can communicate information. The words pervasive and ubiquitous mean "existing everywhere." Pervasive computing devices are completely connected and constantly available.
Pervasive computing relies on the convergence of wireless technologies, advanced electronics and the Internet. The goal of researchers working...
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Parallel Processing Definition
Parallel Processing Definition
In computers, parallel processing is the processing of program instructions by dividing them among multiple processors with the objective of running a program in less time. In the earliest computers, only one program ran at a time. A computation-intensive program that took one hour to run and a tape copying program that took one hour to run would take a total of two hours to run. An early form of parallel processing allowed the interleaved execution of both progra...
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