Adware (ADvertising-supported softWARE) is software that generates advertisements, usually as banner ads or pop-up windows. Adware is usually bundled with other software and installed without your knowledge.
While usually not physically damaging or outright malicious, the intrusive behavior of adware can be annoying and waste system resources. Some particularly aggravating adware spawns new pop-up windows as quickly as you can close them &endash; causing your Internet connection to slow dramatically.
allocation unit
Antivirus programs are software that detect viruses and other malicious software, and then either removes or disables them. An antivirus can block infections from ever reaching your computer, and it can remove existing infections.
A buffer is used to temporarily hold data before transmitting it. A buffer helps compensate for differences in transfer or processing rates between two systems.
A buffer overflow, or buffer overrun, occurs when more data is put into the buffer than it can handle. This is a common result of Denial of Service attacks.
cache file
Cache files are used to store information on a temporary basis for quick access.
A common example of a cache file is a browser cache. Every time you open a Web page, your browser creates a cache file (a temporary copy) of the page's text and graphics. When you open the page again, your browser checks the Web site server for changes. If the page hasn't changed, your browser loads the page from cache on your hard drive, which is faster than originally loading it from the remote server.
A cluster, or allocation unit, is a unit of disk storage that the operating system uses to read or write information. A cluster is the smallest amount of disk space that can be allocated to hold a file.
Each cluster contains from 2 to 8 sectors, depending on the type and size of the disk.
A cookie is a small text file that some Web sites save to your local, hard drive while you are browsing the site. Cookies contain identifying information, such as log in and shopping cart information.
Cookies are useful for loading Web site preferences and login settings, but they can also contain information that can be passed to others without your knowledge, usually for advertising purposes.
cracking
See hacking/cracking.
Denial of Service (DoS) attack
A denial of service (DoS) attack is a type of attack that is designed to crash or disable a system by flooding it with useless traffic. A DoS attack can also destroy files.
A common form of denial of service attack is a buffer overflow attack.
defragment
See fragment/defragment.
A domain name is the text name corresponding to the numeric IP address of a computer on the Internet. Like the IP address, a domain name must be unique. Unlike the IP address, every computer on the Internet does not have to have a domain name.
A domain name has 2 or more parts, separated by dots.
drive-by download
Drive-by downloading is the automatic downloading of software when you visit a Web site, done without your consent and often without any notice. Drive-by-downloads typically exploit security holes or lowered security settings.
No glossary terms begin with this letter.
firewall
A firewall controls the information passing through an Internet connection. A firewall keeps a computer secure from unauthorized intruders by inspecting traffic and only allowing desired communication through.
A firewall can be software, hardware, or a combination of the two.
Over time, as you create, delete, and download files, your computer cannot store data as one unit and instead will split it up and store pieces in various drive locations. A fragmented hard drive has a large amount of such scattered data and can significantly slow PC performance.
Defragmenting reorganizes data so that components are stored closer to each other. Regularly defragmenting hard drives improves drive speed and extends the life of your computer.
No glossary terms begin with this letter.
Hacking is an attempt to gain unauthorized access into a computer or network. A person who makes such attempts is a hacker.
While "hacker" was originally used to describe a person highly skilled in computing, it is now more often used to describe a person who uses that skill for illegal or destructive purposes. Some instead use the term "cracking" for the act of breaching computer security with malicious intent.
Hijackers are a type of spyware that can alter browser settings, redirect Web searches, and replace Web content.
The Internet is a vast network that comprises an immense number of networks using TCP/IP protocols.
Note that the Internet is not synonymous with the World Wide Web. The Web is one of several means (examples of others are FTP and Telnet) for accessing information via the Internet.
Internet Explorer (IE)
Internet Explorer (also "IE") is the Web browser developed by Microsoft. Combined with an Internet connection, it allows you to search for and view information on the World Wide Web. Internet Explorer comes with Windows operating systems and can also be downloaded from Microsoft's Web site.
An IP (Internet Protocol) address is a unique number that identifies a computer or network on the Internet. Every computer or server connected to the Internet has its own IP address, and each Web site has an IP address.
The IP address is four numbers divided by periods, where each number can range from 0 to 255; for example: 216.239.51.100
See also: domain name
iolo
The word iolo is not an acronym, as some may believe. "Iolo" is an archaic Welsh name that is actually pronounced "YO-low." However, many people (including us) pronounce it "eye-OH-low." We've also been told that the word iolo means "to vibrate" in the native Hawaiian language.
No glossary terms begin with this letter.
A keylogger, or keystroke logger, is a Trojan that captures all keystrokes and then records that information to a log file.
With a keylogger, a hacker can capture your logins, passwords, credit card numbers, and any other confidential information that you type. Once collected, this information can be silently transmitted to the Trojan's creator for malicious purposes, such as credit card or bank fraud.
Note: A keylogger can also be a legitimate program that is intentionally and knowingly installed, such as by an employer tracking staff activity.
No glossary terms begin with this letter.
Malware (MALicious softWARE) is a generic term covering a range of software programs that are designed to damage computers or to obtain unauthorized information from computers.
Specific types of malware include viruses, worms, and Trojans.
MB (megabyte)
A megabyte (MB) is a standard unit used to measure the storage capacity of a disk and the amount of computer memory. A megabyte (colloquially, "meg") is equal to approximately one million bytes.
MHz (megahertz)
Megahertz (MHz) is the common measure of the operating speed of a computer's processor. One MHz is equal to one million cycles per second.
The higher the MHz, the better the performance.
network
A network is a group of computers (two or more) and other devices connected by a communications link. A network enables all the computers and devices to interact with each other.
Networks can be small or large, permanently connected through wires or cables, or temporarily connected through phone lines or wireless transmissions.
The largest network is the Internet, which is a worldwide group of networks.
An operating system is the software that controls and manages computer hardware and basic system operations. The operating system loads programs into the computer’s memory, runs these programs, and manages peripherals like disks and printers.
Information is transmitted across the Internet in packets. A packet bundles information so that it can be routed.
A packet consists of a header (which has information on the source, the destination, and how the packet should be handled) and the actual data being transmitted.
Windows uses page files (or, in early versions of Windows, "swap files") as temporary storage when additional memory is needed. A page file creates virtual memory that is saved on your hard drive.
This virtual memory allows Windows to process other programs and services, while reserving RAM for the program in use. The size of the page file is based on the size of the RAM, such as 1.5 or 2 times the amount of installed RAM.
A partition is a section of a hard, physical disk that functions as though it were a physically separate disk.
With Microsoft Windows, the standard scheme is to have a single C: drive where the operating system, applications, and user files reside.
Some users prefer to create additional partitions, so that they can store the operating system separately from other data or run more than one operating system. Partitioning can also increase disk space efficiency and data integrity (if one partition becomes corrupted the rest of the drive is not affected).
A PING (Packet Internet Groper) is used to test whether a system is reachable on an IP network. It is formally called an ICMP Echo.
The computer making an incoming connection attempt sends an ICMP Echo Request packet to the target computer and waits for a response. If the target system responds with an Echo Reply, then the original system knows that computer is reachable.
POP3
POP3 (Post Office Protocol Version 3) is an email protocol that many email programs use to retrieve email messages. This protocol most often transmits on TCP port 110.
port (hardware)
A port is a connection point on a computer that allows you to connect devices that pass data into and out of the computer.
For example, a printer and a modem are connected to a computer through a port. Sample types of ports are parallel, serial, and USB.
A port is an address associated with a program or process on a computer; different applications listen and transmit on different ports. The port number directs packets to the appropriate application.
Ports are assigned to standard protocols such as HTTP and SMTP so that programs know which port to use for a connection. The most well-known port is 80, which transmits HTTP traffic over the World Wide Web.
Prefetching is the movement of data from memory to a cache in anticipation of future access. Examples:
Prefetch files are used by the Windows XP operating system (and later) to start programs faster. By monitoring the files that are used when you start your computer and start applications, the operating system loads the programs it "thinks" you need before you ask for them yourself. This can decrease the time needed to start programs.
Link prefetching is a browser mechanism that pre-loads Web pages that you might visit in the near future. This can speed up browsing by providing a faster response time.
A protocol is a set of standard rules that establish how data is transmitted between computers.
A proxy server is a server located on a network between client software and another server.
A proxy server can be used to regulate Internet communications, by inspecting traffic and determining if anything should be denied transmission.
No glossary terms begin with this letter.
Random access memory is the working memory of a computer where data is temporarily stored for various processes.
A higher amount of RAM means there is more space available for temporary data storage, which can speed processing.
RAT (remote access Trojan, or Remote Administration Tool)
A remote access Trojan (RAT) is a malicious software program that gives someone remote access to and control of a computer.
With a RAT, imposters can send email messages that will appear to be from you; read, modify, or destroy your documents; and use your PC to attack and infect other computers.
The registry is a database that holds configuration settings used by your Windows operating system. The registry is vital to your computer's ability to run correctly. It stores key data that Windows requires and continually references, such as user profiles and settings for installed software and hardware.
The Recycle Bin is where Windows stores deleted files. You can restore files you deleted in error, or you can empty the Recycle Bin to create more disk space and increase your level of protection.
Registry Editor is an advanced tool for viewing and changing settings in your Windows registry. It displays a hierarchical view of your registry contents.
Only manually edit the registry if you know what you are doing; making inaccurate modifications can severely damage your computer. Always back up the registry prior to making any changes.
A router is a networking device that forwards packets across a network to their destinations. A router acts as a junction between two or more networks to transfer data packets among them.
A sector is a portion of the data storage area on a disk. Sectors are the smallest physical storage units on a disk.
A self-extracting file is a compressed file that decompresses itself when executed. Self-extracting files are often used to transmit software over the Internet because they conserve disk space and reduce download time.
A server is a computer that delivers information and software to other computers linked by a network.
Servers come in many forms; for example: application servers, Web servers, database servers, and mail servers.
SMTP
SMTP (Simple Mail Transport Protocol) is an email protocol that many email programs use to send email messages. This protocol most often transmits on TCP port 25.
Spyware is tracking software that is installed on your computer without your notice or consent. It sends information about your computing activities back to its source, usually for advertising purposes, but sometimes for more dangerous purposes such as identity theft or credit card fraud.
The effect of spyware varies depending on what its creator's intentions are and can include consumption of valuable system resources, random lockups, crashes, or slowdowns; Web browser Home page or search page redirection; unwanted software installation; and random or incessant pop-up ads.
SYN is a packet used to synchronize sequence numbers on two connecting computers. A SYN packet is sent when a computer is attempting to connect to a remote computer; the SYN is acknowledged by a SYN/ACK packet sent by the responding computer.
The system tray is located in the Windows taskbar (usually at the bottom of the screen, next to the clock) and contains icons that allow easy access to system functions.
The taskbar contains the Windows Start button, buttons for every open application, and the system tray.
The taskbar generally appears on the bottom of your computer screen, but it can be dragged to either side of the screen or the top of the screen.
The TCP (Transmission Control Protocol) converts data messages generated by an application into packets that can be sent over the IP protocol.
Unlike UDP, TCP is a connection-oriented protocol. TCP guarantees delivery of data and also guarantees that packets are delivered in the same order in which they were sent.
TCP/IP (Transmission Control Protocol/Internet Protocol) is a suite of protocols that form the foundation of Internet communication. It is a standard for transmitting data over networks and enabling communication between a variety of systems.
A trickler is software designed to install or reinstall software by downloading slowly in the background so that the download is less noticeable. Tricklers are typically used to enable a spyware program to silently install or to reinstall itself after a user has removed components of the program from his or her computer.
A Trojan, or Trojan horse, is a software program that appears to be desirable or useful, but intentionally does something you do not expect.
The effects of Trojans can range from simply displaying pop-up ads to destroying files or enabling the theft of data.
Trojans are distributed in executable files, such as through email attachments, CDs, and Internet downloads. People can be lured into installing a Trojan because it appears that it will serve a legitimate purpose. Unlike viruses and worms, a Trojan is not designed to make automatic copies of itself. However, Trojans can carry viruses and other malicious software within them.
Some specific types of Trojans include keyloggers and RATs.
The UDP (User Datagram Protocol) converts data messages generated by an application into packets that can be sent over networks.
Unlike TCP, UDP is a connection-less protocol. It does not verify that a connection has been established with the receiving system.
UDP is often used for streaming video and audio.
A computer virus is a software program designed to alter the operation of a computer.
Most viruses are malicious and intended to cause damage, but even a benign virus can harm a system. Viruses can damage files, software programs, the registry, and hardware.
Viruses are distributed in executable files, such as through email attachments, CDs, and Internet downloads. A virus infection occurs when the infected file is run. A virus also automatically replicates, or makes copies of itself, by secretly embedding its programming code into other programs.
The term "virus" is often used as a generic, collective reference that includes other types of malicious programs, such as worms and Trojans.
A virus definition is a file that contains virus signatures (see below) and other information used by an antivirus to detect, remove and repair known viruses. When an antivirus scans your computer, it is searching for qualities that match information in its definition files.
Keeping the virus definitions up-to-date is vital to protecting your computer.
A virus signature is a unique string of code that makes up of all or part of a computer virus, worm, or other malicious code. The virus signature is like a fingerprint that can be used to identify specific viruses. Virus signatures are saved in a virus definition (see above).
Windows Explorer
Windows Explorer (also "Explorer") displays a hierarchical view of the drives, folders, and files on your computer. Using Windows Explorer, you can open, copy, move, rename, and search for files and folders. Windows Explorer is an application that is part of Windows operating systems.
The World Wide Web, or simply "Web", is the largest and most commonly used network on the Internet. The Web uses the HTTP protocol to transmit Web pages and other information.
Note that the World Wide Web is not synonymous with the Internet. The Web is one of several means for accessing information via the Internet.
A computer worm is a software program designed to reproduce and spread among computers.
Most worms are malicious and intended to overwhelm system memory or network bandwidth. Worms can crash an entire network of computers or an individual computer.
Worms are generally distributed in email attachments or through unprotected Internet activity. A worm spreads very rapidly because it is self-contained. It replicates itself and, unlike viruses, a worm does not need to infect another program to spread.
No glossary terms begin with this letter.
No glossary terms begin with this letter.
zombie
A zombie is computer that has had its security compromised and is remotely controlled, such as by a RAT.