Setting up Your Defenses

Maintaining Your Defenses

Defending Mobile Device

How Computers Work

Computer and Device Defense Database

Carlo On the Go
Carlo On the Go

Doctor Keen, Scout, and Carlo bring you tips for keeping your computer, mobile devices, and data safe. From the different parts of the computer to the different ways to connect to the Internet, they cover it all.

Computer and Device Maintenance and Defense

Here you will find information about the threats to your computer and devices and steps you can take to protect them.

Setting Up Your Defenses

Setting up Your Defenses
Tips for protecting your devices and data before entering Cyberspace.

Maintaining Your Defenses

Maintaining Your Defenses
Always be on your guard and keep your defenses strong to stay protected.

Defending Mobile Devices

Defending Mobile Devices
Smartphones and laptops need protection from malware and criminals too.

How Computers Work

Computers are a collection of hardware and software components working together to do a variety of tasks. Any of these components can wear out or break and cause your computer to malfunction.

On the How Computers Work page, you can learn more about what the different components do, what can happen when something goes wrong with them, and tips for taking care of them.

Computer and Device Defense Database

These and other cyber definitions can be found in the Cyberpedia.



A group of computers and devices connected by communications channels, either wired or wireless, which allows users to communicate and share resources, like peripherals, with each other.

Network Interface Card

A hardware card in your computer that lets you connect your computer to a network. Each network card has a unique address that identifies the computer on the network.

Learn more: How Computers Work



The software that allows you to interact with the computer and run the programs on it. It is like the computer's spine, connecting the "brain", the CPU, to the rest of the body, the programs and devices. The most common operating systems for desktop computers are Windows, Mac OS, and UNIX.

Learn more: How Computers Work


P2P Network

See Peer-to-Peer Network


A small chunk of data sent over a network.

Packet Sniffer

A device or software program that spies on packets traveling between networked computers, collecting them so a cyber criminal can look at them later. Packet sniffers run in the background collecting data but don’t actually send any data out, so they can be very hard to detect. They can be used in helpful ways, like to gain information about a network intrusion, but they can also be used in criminal ways, like to spy on other network users and collect personal information.

Learn more: Computer and Device Defense

Parental Controls

Software that your parent or trusted adult can use to help make your Internet experience more safe. These controls can let them set which games you can play, which programs you can use, which websites you can visit, and when. While this may sound like they are trying to control your online life, these controls are really to protect you from stumbling across content that might make you afraid or uncomfortable.

Learn more: Computer and Device Defense


A series of letters, numbers, and special characters that you use to get access to a protected computer, network, or software program. Passwords make sure that information is only accessed by people who are supposed to see it.

Learn more: Computer and Device Defense


A small software program designed to update a program or fix security vulnerabilities or bugs in it.

Learn more: Maintaining Your Defenses


Short for Personal Digital Assistant, an electronic mobile device that can be used to manage your personal information like your schedule, address book, and to-do list. Many PDAs now have some of the same functions as computers, mobile phones, and digital audio players and can access the Internet.

Learn more: Defending Mobile Devices

Peer-to-Peer Network

A type of network that allows computer users to share everything from files to network bandwidth with one another. A user must install software to access the network, then they can search through and download the files of any computer on the network. They can be risky because they give others direct access to your files, and many peer-to-peer programs don’t allow their users to have a firewall in place so they can leave your computer open for a malware infection.

Learn more: Computer and Device Defense


A device that is not necessary for a computer to function but that helps you use it and the Internet. These include: keyboards, mice, monitors, printers, scanners, external hard drives, USB flash drives, speakers, modems and routers.

Learn more: How Computers Work


A small computer program that adds features to a software program. Some popular plug-ins, like video and music players, work with web browsing software to add special features. Other plug-ins help to add extra security or make the program more efficient.

Learn more: How Computers Work


A web browser window that appears when you click a link or visit a website in another window. These pop-ups are frequently advertisements and can sometimes be caused by adware.

Learn more: Computer and Device Defense

Pop-up Blocker

Defensive software that prevents pop-ups from displaying. They are usually built into a web browser or can be added as a plug-in. Since not all pop-ups are risky and not all are advertisements, most pop-up blockers will let you know when they have blocked one and allow you to unblock it if you need to.

Learn more: Setting Up Your Defenses

Proxy Server

See Server, Proxy



Isolating malware discovered during a scan by anti-malware software into a special area of the hard drive so it can't infect other files in the computer.

Learn more: Computer and Device Defense



Short for Random Access Memory, a type of computer memory that is used for short-term data storage. In most computers, it is a circuit board installed in the motherboard. Random Access means that the stored data can be accessed in any order, regardless of where it is physically stored on the board. It is like a bucket to store data in, whenever you need to retrieve it, you just reach in the bucket and grab it. Also see SAM.

Learn more: How Computers Work

Remote Backup

A service that lets users back up and store their data on a distant server. Some remote services will regularly back up data without a user needing to do anything.

Learn more: Back Up Your Data

Rogue iFrames

When a cyber criminal hacks into a website that contains an iFrame, special HTML code that inserts outside content into a website, and inserts their own iFrame content that contains malware. Since the object appears on a trusted website, users are much more likely to click on the hackerís content.

Learn more: Setting Up Your Defenses

Rogue Security Software

Software that claims to protect your computer but actually infects it with all kinds of malware.

Learn more: Computer and Device Defense


A device that connects one network with another and decides how to best transmit information between them to make sure that it gets to its destination quickly and accurately.

Learn more: How Computers Work



Short for Serial Access Memory, a type of computer memory that is used for short-term data storage. It is slower than RAM because it has to be accessed in the order it was stored in, like a cassette tape. SAM is useful for long connected bits of data that don't need to be accessed randomly, like a video buffer.

Learn more: How Computers Work


A type of malware that tries to scare victims into downloading something, usually through a fake pop-up. Sometimes the download can be harmless but sometimes it is rogue security software or contains malware.

Learn more: Computer and Device Defenses


A computer on a network that provides services, like email, online games, and website hosting, to clients.

Server, Mail

A server that is dedicated to providing email services.

Server, Proxy

A server that has a job to do with information travelling between a computer and another server on the network. Some proxy servers protect users' personal information by encrypting their connection, others block certain websites or scan for malware before the data is delivered. They can also be used for bad purposes, like to access a website that someone does not have permission to access.

Server, Web

A server that is dedicated to hosting websites.


Software that you can download from the Internet that is normally free for a period of time. Before you can use it, you must accept the licensing agreement, which will tell you how long you can use the program for free before needing to pay for it. This can be a length of time, like a week or a month, or it could be after opening the program a certain number of times. Also see Freeware.

Learn more: Be Careful With Files


An electronic mobile device that combines the features of a phone and a PDA and can access the Internet through the phone service.

Learn more: Defending Mobile Devices


A set of instructions written in computer code that tells your device's hardware what to do, the computer's "programs." The kind of software you can use on a device is limited by the kind of hardware you have.

Learn more: How Computers Work

Sound Card

A hardware card in your computer that processes and outputs sound. It can work with both the internal and external speakers to provide sound.

Learn more: How Computers Work


The Internet version of junk mail, a cyber crime where someone sends the same message to several people, usually to advertise something. Spammers collect email addresses for their attacks by illegally scanning cookies or looking for addresses on websites.

Learn more: Cyber Crimes and Criminals

Spam Filter

Software that filters spam out of your email.

Learn more: Setting Up Your Defenses


A type of malware that spies on what you do on the Internet and can steal information about you from your computer.

Learn more: Maintaining Your Defenses

Surge Protector

An extension for an electrical outlet that allows you to plug multiple devices into one outlet and also protects those devices from power "surges."

Learn more: How Computers Work


Tablet PC

A portable personal computer with a touchscreen. You usually use an onscreen keyboard and stylus rather than a keyboard and mouse to interact with a tablet PC.

Thumb Drive

See USB Flash Drive

Trojan Horse

A type of malware disguised as legitimate software. Attackers can either attach a Trojan horse to useful software, or trick you into thinking the Trojan horse itself is useful software. Trojan horses are different from viruses and worms because they cannot replicate themselves.

Learn more: Maintaining Your Defenses



Sending files from a computer or device to a server or computer somewhere on the Internet.


Short for Universal Serial Bus, a type of port on your computer that you can plug devices into.

Learn more: How Computers Work

USB Flash Drive

A portable hard drive that plugs into a USB port.

Learn more: How Computers Work



Software or hardware that is announced years before an actual release date is planned, and sometimes it is never released.


A type of malware that can modify, delete or steal your files, make your system crash or take over your machine. Viruses can infect your computer if you use a file containing one, called a "host file." Once you release a virus, it can infect other files just like a real virus spreads to other people and cells.

Learn more: Maintaining Your Defenses


Security holes or weaknesses in a piece of software that a cyber criminal can take advantage of.

Learn more: Maintaining Your Defenses



A video camera that can be used as a peripheral device for your computer. Webcams feed video in real-time rather than recording it to a storage device.

Web Server

See Server, Web.


Short for Wireless Fidelity, a way to connect to the Internet using radio waves to connect devices instead of using wires and cables.

Learn more: Defending Mobile Devices

WiFi Hotspot

A location where a WiFi wireless network is available to connect to.


A way to connect to the Internet with a wireless network interface card or mobile device, using radio waves instead of wires and cables. There must be a WiFi, WiMax, or cellular network in range of the device, and connection speeds vary a lot, depending on the device, the distance from the access point, and the strength of the signal.


A type of malware that copies itself and uses a computer network to send these copies to other computers on the network. Unlike viruses, they do not require you to open a file in order to spread. Worms can consume bandwidth on a network and install other malware that gives hackers access and helps them create zombie computers for a botnet.

Learn more: Maintaining Your Defenses


ZIP File

A data compression and archive format. A ZIP file contains one or more files that have usually been compressed to reduce file size.




A type of malware that makes advertisements appear on your computer. Adware is usually included with other programs, so that when you install the program you want, you also install the adware.

Learn more: Maintaining Your Defenses

Anti-Malware Software

Defensive software that protects your computer from malware like viruses, spyware, and Trojan horses. It scans your computer for malware and removes any that it finds. It can also run continuously in the background and catch malware infections right when they happen. Anti-Malware software needs to be updated regularly to be able to catch the latest malware.

Learn more: Computer and Device Defense

Anti-Spyware Software

Anti-Malware software that focuses on protecting your computer from spyware.

Learn more: Computer and Device Defense

Anti-Virus Software

Anti-Malware software that focuses on protecting your computer from viruses.

Learn more: Computer and Device Defense


A file that is attached to an email message. You can tell that an email has an attachment if it has a paper clip icon. Attachments can be text files, pictures or music, and they can also contain malware.

Learn more: Be Careful With Files



Copying the data from your hard drive to a storage device like a CD, DVD, external hard drive or thumb drive. Backing up your data regularly will help reduce the damage when something bad happens to your computer, like a malware infection or hardware failure.

Learn more: Back Up Your Data

Banner Ads

A type of online advertisement that is "embedded" or part of the webpage. They come in a variety of sizes, but are usually a rectangular box. Banner ads can look like games, have video or sound, and can even appear to float on top of the webpage. They are designed to tempt you away from the site you are visiting by looking fun and exciting.


Short for "binary digit," the smallest unit of computer data storage. A bit represents either a one (1) or zero (0), which a computer reads as "on" or "off."

There are 8 bits in a byte. A bit is like a letter and a byte like a word. Each individual letter carries information ("on" or "off") but no real meaning. When these letters are combined to form words, however, they can be used to convey a variety of information.


A data-writing format that uses a blue-violet laser to write data to a disc. Since the blue-violet laser has a shorter wavelength than a traditional red laser, it is more accurate and data can be stored in smaller packets. A Blu-ray disc can hold as much as 500 gigabytes, which is as much data as 28 top-quality DVDs.


A type of Internet connection that uses cable television or DSL lines. Broadband connections have a "broad" bandwidth and are up to 70 times faster than dial-up connections. They allow you to stay connected to the Internet all the time, so they can put your computer at a higher risk for malware infection.

Learn more: Disconnect Your Computer to Protect It

Browser Hijacker

A type of malware that changes the behavior of your web browser. Some of the things browser hijackers can do include replacing your browserís home page, adding new bookmarks or favorites, redirecting you to a website you didn't want to go to, and covering your desktop with pop-ups.

Learn more: Computer and Device Defense


Allows data to continue to be downloaded to you computer while a program plays the first part of the file that's already been downloaded. Buffers let you watch a streaming video or listen to a song without skips and jumps because the program never has to stop playing in order to download more.


A malfunction of a software program. Bugs can be caused by something as simple as a typo in the program's code, or by many complicated procedures running at the same time, or even intentionally caused by hackers and cyber criminals.


The second-smallest unit of computer data storage. There are 8 bits in a byte.

See also Kilobyte, Megabyte, and Gigabyte



Short for Compact Disc, a data storage device. CDs are round, shiny plastic discs that a computer can use a red laser to write data to. An average CD can hold about 700 megabytes of data.

Learn more: Back Up Your Data

Cloud Computing

Using computing services and programs through a network. With cloud computing, instead of being stored on your computer's hard drive, your data and programs are stored on servers located far away, or "in the cloud." You use your computer and Internet connection to access those servers and a web browser to run programs like word processors and email programs.


Small text files that websites save in your web browser to store information like your username and password. Some malware can scan your cookies to get information about you. You can set your browser to not accept cookies from any website or to warn you before you accept them.

Learn more: Computer and Device Defense


Short for Central Processing Unit, a chip that functions as the brains of the computer. The CPU performs the majority of the millions of calculations the computer needs to make in order to function.

Learn more: How Computers Work


Data Compression

Storing information using fewer bytes than the original file used. A .ZIP file is a common data compression type.

Data Rot

Also known as bit rot, the gradual decay of information stored on any device. For example, if you leave a USB flash drive alone for several years and then try to use it, you might find that some of the files cannot be accessed.


Also called "defragging," a process that helps your computer run better. As you use and save files on your computer, it has to find new places on the hard drive to put them. Sometimes it breaks them down into pieces, or "fragments", and puts them in different locations. This slows down your computer because it has to find all the right pieces before anything can run. Defragging helps speed things up by taking the scattered fragments and reorganizing them closer together.

Learn more: How Computers Work

Device Driver

A software program that controls a hardware component or device attached to your computer. It acts as a translator for the operating system, converting the operating system's instructions into messages that the device can understand.

Learn more: How Computers Work


The slowest and least expensive way to connect to the Internet, uses a modem and transfers data through the telephone line. You have to dial in to connect and hang up to disconnect, and connections can also be easily disrupted by noise on the line.


Getting information from a computer or server somewhere on the Internet and transferring it to your computer or device.

Learn more: Be Careful With Files


Short for Digital Subscriber Line, a way to connect to the Internet that uses a modem and transfers data through the telephone line. DSL signals use a higher frequency than dial-up signals and so can be sent through the telephone line at the same time as phone signals.


Short for Digital Versatile Disc, a data storage device. DVDs are round, shiny plastic discs that a computer can use a red laser to write data to. An average DVD can hold about 4.7 gigabytes of data.

Learn more: Back Up Your Data



Transforming text or data into an unreadable form so that only people with access to the right software can "decrypt", or decode it. Encrypting data makes it harder for cyber criminals to use it for cyber crimes.

Learn more: Setting Up Your Defenses


A portable electronic device for reading digital books and magazines.

Learn more: Defending Mobile Devices


An inexpensive networking method commonly used for LANs, or local area networks. A basic ethernet network has two or more computers with a network interface card installed, a networking hub that sends data to and from the machines on the network, and cables that connect each computer to the hub.



A collection of bytes of data that remains available for software programs to use again even after the current program has finished using it.

File Attachment

See Attachment.

File Compression

See Data Compression.

Fiber Optics

A way to connect to the Internet that uses lines made from flexible, transparent fibers and transmits data with light pulses rather than with electrical signals like dial-up and DSL. Fiber optic lines can cover longer distances and handle more traffic than copper telephone lines, but they are not available everywhere and frequently must be installed in order to bring service to an area.


A defensive software program that acts like a security guard and monitors and controls the traffic coming into and out of your machine from a network. Firewalls can help protect your computer from malware and intruders.

Learn more: Setting Up Your Defenses


Short for File Transfer Protocol, the rules and formats that apply to copying files from one computer to another over a network. With FTP, files are uploaded and downloaded from a person's computer to a server.



A unit of computer data storage. There are 1024 megabytes in 1 gigabyte.

Graphics Card

A hardware card in your computer that processes and outputs images to the computer's monitor. The graphics card receives information from the CPU about what to display, decides how to use the pixels on the screen to display that image, and sends that information to the monitor. For 3-D images, it first creates everything out of straight lines, called a "wireframe," and then fills in all the lighting, texture and color. In a fast-paced game, it has to do this around sixty times per second.

Learn more: How Computer Work


Short for Graphical User Interface, a type of interface used for operating systems that allows users to see files and manipulate them with a mouse or stylus. Before GUIs, most operating systems displayed the computerís data as lines of text and files were manipulated by entering complicated lines of text, or "command lines."

Learn more: How Computers Work


Hard Drive

The hardware component of a computer where it stores data for long-term use. It contains a hard, disk-shaped platter made of a magnetic material, and uses magnets to store digital data on the platter. The magnetic material allows the computer to easily erase and rewrite the data whenever it needs to.

Learn more: How Computers Work


The physical components of a computer, usually contained within the computer's main case or tower.

Learn more: How Computers Work


The web server that a website's files are stored on.



A small image that represents a website, software program or file in a GUI.


A network that connects millions of computers around the world.


An internal, secured network that functions like the Internet but doesn't actually connect to the Internet. Intranets operate through a LAN and are used by companies to securely and easily share information and devices from anywhere within the business. Usually, only employees who work for that company can access its intranet, and sometimes only from a company computer.



Changing the limitations of a device so you can do something that the manufacturer didn’t want you to do. People jailbreak mobile devices so that they can change settings or download programs that are normally unavailable to them. Although it is not illegal to jailbreak a device, it usually voids your warranty, so if something happens to it, the manufacturer doesn’t have to replace it. It can also make it easier for hackers to break into your mobile device.

Learn more: Defending Mobile Devices

Joke Programs

Prank software programs that cause your computer to behave strangely or display fake error messages that trick you into thinking something is wrong. They can change the appearance of your computer's desktop or mouse cursor, or even make it look like your hard drive has been erased. Joke programs are not malware because they do not harm your computer, but they can make it difficult to use.

Learn more: Computer and Device Defense


Key Logger

Software that records the letters and characters you type on the keyboard. Key loggers can be used for parental controls, in the workplace to make sure employees are doing what they are supposed to, and during testing to see what causes errors in a program. Some malware also uses key loggers to capture people's passwords and personal information as they type them.

Learn more: Computer and Device Defenses


A unit of computer data storage. There are 1024 bytes in 1 kilobyte.



Short for Local Area Network, a computer network that covers a relatively small area, like a building. Each computer in a LAN can access and share data with any other device in the network. This allows a group of people to share information and peripherals, such as printers, and to communicate with each other through the network by sending messages or chatting.


Malicious Search Results

Fake websites that show up in a search engine's results that can actually take you to risky websites that infect your computer with malware. Sometimes cyber criminals fill these websites with common keywords or phrases people search for to trick them into visiting the site.

Learn more: Computer and Device Defense


Short for Malicious Software, software that harms your computer or steals your data.

Learn more: Computer and Device Defense


A unit of computer data storage. There are 1024 kilobytes in 1 megabyte.

Memory Leaks

When a program doesn't properly clear the memory after closing, making it unusable for other programs. Over time, this memory loss can lead to a slower computer or even a computer that constantly crashes. Most memory leaks are caused by malware or bugs.

Learn more: Computer and Device Defense


The chip that contains a computer's CPU.

Learn more: How Computers Work

Misleading Applications

A type of malware that mimics anti-malware software. They can install themselves when you are browsing the Internet, or they can trick you into installing them by imitating system alert messages.

Learn more: Computer and Device Defense

Mobile Hotspot

A device that can act as a wireless router, allowing nearby devices to connect to the Internet as if they were connecting to any other wireless network. Smart phones, USB modems, and some cars can act as hot spots.

Learn more: Defending Mobile Devices

Mobile Device

A portable electronic device. Many mobile devices can use wireless or cell phone networks to connect to the Internet.

Learn more: Defending Mobile Devices


A peripheral device that converts analog signals into digital signals, and vice versa. To connect to the Internet over a telephone, cable or DSL line, which are made out of metal wires, you need a modem to convert your computer's digital signal into an analog signal that it can send over the wires. The modem translates the analog data it receives back into a digital signal that your computer can understand.

Learn more: How Computers Work


Also called a logic board or mainboard, a board with electrical circuits printed on it that holds many components essential for a computerís function, like the CPU and graphics card. The electrical circuits on the board allow the components to receive power and communicate with each other.

Learn more: How Computers Work