A destructive program that masquerades as a benign application. Unlike viruses, Trojan horses do not replicate themselves but they can be just as destructive. One of the most insidious types of Trojan horse is a program that claims to rid your computer of viruses but instead introduces viruses onto your computer.

The term comes from a story in Homer's Iliad, in which the Greeks give a giant wooden horse to their foes, the Trojans, ostensibly as a peace offering. But after the Trojans drag the horse inside their city walls, Greek soldiers sneak out of the horse's hollow belly and open the city gates, allowing their compatriots to pour in and capture Troy.

An error or defect in software or hardware that causes a program to malfunction. Often a bug is caused by conflicts in software when applications try to run in tandem. According to folklore, the first computer bug was an actual bug. Discovered in 1945 at Harvard, a moth trapped between two electrical relays of the Mark II Aiken Relay Calculator caused the whole machine to shut down.

Short for keyboard, video, mouse switch, a hardware device that enables a single keyboard, video monitor and mouse to control more than one computer one at a time.

KVM switches are popular among users who have upgraded their home PC systems and want to still use their old computers but do not want to invest in a second keyboard, monitor and mouse. KVM switches are also used by business to save money when one person uses more than one computer and in server farms where it is only necessary to periodically access each separate server in the farm one at a time.

Any machine or component that attaches to a computer. Examples of devicesinclude disk drives, printers, mice, and modems. These particular devices fall into the category of peripheral devices because they are separate from the main computer.

Most devices, whether peripheral or not, require a program called a device driver that acts as a translator, converting general commands from an application into specific commands that the device understands.

Refers to objects that you can actually touch, like disks, disk drives,display screens, keyboards, printers, boards, and chips. In contrast, software is untouchable. Software exists as ideas, concepts, and symbols, but it has no substance.

Books provide a useful analogy. The pages and the ink are the hardware, while the words, sentences, paragraphs, and the overall meaning are the software. A computer without software is like a book full of blank pages -- you need software to make the computer useful just as you need words to make a book meaningful.

Also spelled "Webring," a series of Web sites linked together in a .ring. that by clicking through all of the sites in the ring the visitor will eventually come back to the originating site. All of the sites within the ring share a similar topic or purpose. There are Web rings on topics such as computer games and technology, hobbies such as quilting or stamp collecting, sports, traveling, pop culture, music, cars, etc.

Web rings are a way for sites to generate more traffic by encouraging users to visit the other sites within the ring. Sites in the ring typically have an icon or graphic that indicates that it is part of a specific Web ring and visitors have the option of choosing the .next. or .previous. site in the ring.

An identifier for a computer or device on a TCP/IP network. Networks using the TCP/IP protocol route messages based on the IP address of the destination. The format of an IP address is a 32-bit numeric address written as four numbers separated by periods. Each number can be zero to 255. For example, 1.160.10.240 could be an IP address. Within an isolated network, you can assign IP addresses at random as long as each one is unique. However, connecting a private network to the Internet requires using registered IP addresses (called Internet addresses) to avoid duplicates.

The four numbers in an IP address are used in different ways to identify a particular network and a host on that network. Three regional Internet registries -- ARIN, RIPE NCC and APNIC -- assign Internet addresses from the following three classes.

• Class A - supports 16 million hosts on each of 126 networks
• Class B - supports 65,000 hosts on each of 16,000 networks
• Class C - supports 254 hosts on each of 2 million networks
  
  The number of unassigned Internet addresses is running out, so a new classless scheme called CIDR is gradually replacing the system based on classes A, B, and C and is tied to adoption of IPv6.

An agreed-upon format for transmitting data between two devices. The protocol determines the following:

• the type of error checking to be used data compression method, if any
• how the sending device will indicate that it has finished sending a message
• how the receiving device will indicate that it has received a message
  
  There are a variety of standard protocols from which programmers can choose. Each has particular advantages and disadvantages; for example, some are simpler than others, some are more reliable, and some are faster.
  
  From a user's point of view, the only interesting aspect about protocols is that your computer or device must support the right ones if you want to communicate with other computers. The protocol can be implemented either in hardware or in software.

Recorded evidence of a system intrusion, typically as part of an intrusion detection system (IDS). When a malicious attack is launched against asystem, the attack typically leaves evidence of the intrusion in the system.s logs. Each intrusion leaves a kind of footprint behind (e.g., unauthorized software executions, failed logins, misuse of administrative privileges, file and directory access) that administrators can document and use to prevent the same attacks in the future. By keeping tables of intrusion signatures and instructing devices in the IDS to look for the intrusion signatures, a system.s security is strengthened against malicious attacks. Because each signature is different, it is possible for system administrators to determine by looking at the intrusion signature what the intrusion was, how and when it was perpetrated, and even how skilled the intruder is.

(v.) (1) To deliberately post derogatory or inflammatory comments to a community forum, chat rooms, newsgroup, and/or a blog in order to bait other users into responding.
(2) To surf the Internet.
(3) To hang around a chat room reading the posts instead of contributing to the chat.
(n.) One who performs any of the above actions.

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