Computer Terms & Definitions

Do you ever feel like you know absolutely nothing about your computer?  When you have a problem and call for technical support, does it sound like the person on the other end of the line is speaking a foreign language?  Below you will find a list of common computer terms along with their definitions which should make you feel better the next time you find yourself in a conversation about computers. 

Applet- This a Java program that can be embedded in a Web page. The difference between a standard Java application and a Java applet is that applets can't access system resources on the local computer. System files and serial devices (modems, printers, scanners, etc.) cannot be called or used by the applet. This is for security reasons -- nobody wants their system wiped out by a malicious applet on some wacko's Web site. Applets have helped make the Web more dynamic and functional as well as giving an helpful boost to the Java programming language.

Bitmap-  Most pictures you see on your computer, including the ones found on the Internet, are composed of bitmaps. A bitmap is a really just a map of dots (or bits, hence the name) that looks like a picture as long as you're not like 2 inches from the screen. Common bitmap filetypes include BMP, JPEG, GIF, PICT, PCX, and TIFF. Because bitmap images are made up of a bunch of dots, if you zoom in on a bitmap, it gets all blocky. Vector graphics (created in programs such as Freehand, Illustrator, or CorelDraw) scale up much better without getting blocky.

Bookmark- Similar to a real-life bookmark, an Internet bookmark acts as a marker for a website. (In Internet Explorer, they're called "Favorites".) When using a web browser, you can simply select a bookmark from the browser's menu to go to a certain site. This way, you don't have to do the redundant typing-in of the URL every time you visit one of your favorite sites. Plus, who remembers those 200-character addresses anyway? In most browsers, to create a bookmark, you simply choose "Add Bookmark" from the Bookmarks menu when you're at a page which you'd like to bookmark.

BPS- Stands for "Bits Per Second." (The "b" is lowercase because it stands for bits, not bytes.) This is the standard way of measuring how fast data moves across a network or phone system. A 56K modem can transfer 56,700 bits per second.

Browser-  It's what you're probably using to read this right now. A browser, or web browser (same thing), is the program people use as their interface to the World Wide Web. It interprets HTML code including text, images, hypertext links, java applets, etc. allowing you to view web sites and navigate from one to another. Currently, the two most popular browsers are Microsoft Internet Explorer and Netscape Communicator.

Byte-  A byte is a set of bits that represent a single character in the computer's memory. Do not confuse this with "bite", which means something totally different. There are 8 bits in a byte. Bytes are typically used to measure hard disk storage and computer memory (megabytes, gigabytes, etc.) Abbreviation: "B".

Cache-  Pronounced like "cash", not "catch", and definitely not "cashé". There are many different types of caches but they all serve basically the same purpose. They store recently-used information in a place where it can be accessed extremely fast. For example, a web browser like Internet Explorer uses a cache to store the pages, images, sounds, and URLs of web sites you visit on your hard drive. With this neat strategy, when you visit a page you have recently been to, everything doesn't have to be downloaded to your computer all over again. Because accessing your computer's hard disk is much faster than accessing the Internet, this speeds up web browsing significantly.
Your computer also uses disk caching, which stores information you have recently read from your hard disk in the computer's RAM. Since accessing RAM is much faster than reading data off the hard disk, this helps speed up common functions on your computer. One more type of cache is a processor cache which stores small amounts of information on or next to the processor. This helps make the processing of common instructions much more efficient, thereby speeding up computation time.

Cookie-  In computer terminology, a cookie is data sent to your computer by a web server that records your actions on a certain web site. It's a lot like a preference file for a program on your computer. Whenever you visit the site after being sent the cookie, the site will load according to the information stored in the cookie. For example, some sites can remember information like your user name and password, so you don't have to re-enter it each time you visit the site. Cookies are what allow you to have personalized web sites like "My Excite" or "My Yahoo" in which you can customize what is displayed on the page.

Cyberspace- Unlike most computer terms, "cyberspace" doesn't have a standard, objective definition. Instead, it is used metaphorically to describe the virtual world of computers. For example, an object in cyberspace is just a block of data floating around on some computer system or network. With the advent of the Internet, cyberspace now also is used to refer to the global network of computers. So, after sending an e-mail to a friend, you could say you sent the message to him or her through cyberspace. However, use this term sparingly, as it is a popular newbie term and is already well overused.

Default- This is the default term used to describe a preset value for some option in a computer program. It is used when a setting is not specified by the user.  Typically default settings in programs are set to what most people would choose, so there's no big reason to change them. However, if you're one of those people who has to customize everything and can't stand having a single option set to default, feel free to do whatever you want.
The term default can also be used as a verb. If a custom setting won't work for some reason, the program will "default" to the default setting. If that's not enough, default can also be used as an adjective. For example, say you're working on computer that is on a network and you print something when there is no printer specified. If you don't get some nasty error about how you should have selected a printer, your work will be printed on a default printer.

Defragment-  Defragmenting your hard drive is a great way to boost the performance of your computer. Though the term "defragment" sounds painfully abrasive, it is a rather simple and helpful process. A defragmented hard drive is a happy hard drive.
Adding and deleting files from your hard drive is about as common of a computer task as there is. Unfortunately, this process isn't always done very efficiently. For example, when you delete a bunch of little files and add a new large file, the file may get broken up into multiple sections on the hard drive. The computer will still read the newly added file as a single, valid file, but it will have to scan various parts of the drive to read the file in. Because hard disk seek time is one of the biggest bottlenecks in a computer's performance, this can drag your computer's speed down quite a bit. If you have a ton of "fragmented" files on your hard disk, you might hear a bunch of extra grinding, sputtering, and other weird noises coming from your computer.
You computer doesn't like having fragmented files any more than you do. This is why defragmenting your hard drive is such a good idea. When you start to hear extra grinding sounds, or your computer doesn't seem to open files as quickly, it's time to defragment. With Windows, you can use the pre-installed Intel defragment program to defragment your hard drive. You can also use a commercial software program like Norton Utilities to defragment your hard drive more efficiently and with more options. For Mac users, Norton Utilities or another hard drive utility option is the only way to go. If you use your computer daily, defragmenting your hard drive once a month should keep the fragment-fiends away.

DIMM- Stands for "Dual In-Line Memory Module." It is a type of computer memory. A DIMM is a small circuit board that holds memory chips. It uses a 64-bit bus to the memory, whereas a single in-line memory module (SIMM) only has a 32-bit path. Because DIMMs have faster data transfer capabilities than SIMMs, they have pretty much replaced SIMMs.

DLL- Stands for "Dynamic Link Library." A .dll file contains a library of functions and other information that can be accessed by a Windows program. When the program is launched, a link to the .dll file is created. If a static link is created, the .dll file will be in use as long as the program is active. If a dynamic link is created, the .dll file will only be used when needed. Because of this, .dll files allow programs to use resources, such as memory and hard drive space, more efficiently.
DLL files can also be used by more than one program. In fact, they can even be used by multiple programs at the same time. Amazing, isn't it? Some DLLs come with the Windows operating system while others are added when new programs are installed. You typically don't want to open a .dll file directly, since the program that uses it will automatically load it if needed. Though DLL filenames usally end in ".dll", they can also end in .exe, .drv, and .fon, just to make things more confusing, of course.

DNS- Stands for "Domain Name System." The primary purpose of DNS is to keep Web surfers sane. Without DNS, we'd have to remember the IP address of every site we wanted to visit, as opposed to just the name. Now, I have some computer science friends who might prefer this, but for normal people, names are much easier to remember. The reason for the Domain Name System is that web sites are actually located by their IP addresses. So, when you type in "http://www.adobe.com", the computer doesn't immediately know that it should look for Adobe's web site. Instead, it sends a request to the nearest DNS server, which matches an IP address to the domain name and then connects you to the server with that IP number. And we just take it for granted.

Domain Name- This is the name that identifies an web site. For example, "apple.com" is the domain name of Apple Computer's web site. A single web server may have more than one domain name, but a single domain name points to only one machine. To use Apple Computer as an example again, www.apple.com, support.apple.com, and store.apple.com could be served on one to three machines. It is also possible, and quite common, for a domain name to be registered, but not be connected to an actual machine. The reason for this is usually so that a company or group can have e-mail addresses at a certain domain without having to maintain a web site. In these cases, there still must be a machine to handle the mail of the listed domain name.

Download- This is the process in which data is sent to your computer. Whenever you get information off the Internet, you are downloading it to your computer. For example, you might have to download an upgrade for your computer's operating system in order to play a new game (especially if you're using Windows). The opposite of this process, sending information to another computer, is called uploading.

Driver- A driver is a small file that helps the computer communicates with a certain hardware device. It contains information needed to recognize and control the device which the computer does not already have. In Windows-based PCs, a driver is often packaged as a dynamic link library (DLL) file; in Macs, most hardware devices don't need drivers, but the ones that do usually come with a software driver in the form of a System Extension.

DSL- Stands for "Digital Subscriber Line." It's basically another medium for sending data over regular phone lines. However, a DSL circuit is much faster than a regular phone connection, even though the wires it uses are copper like your typical phone lines. An asymmetric DSL (ADSL) connection allows download speeds of up to about 1.5 megabits (not megabytes) per second, and upload speeds of 128 kilobits per second. That is why it's called ADSL and not just DSL (because of the asymmetric speeds). There is also a "Symmetric Digital Subscriber Line" (SDSL) which is similar to ADSL, but allows data transfer speeds of 384 Kilobits per second in both directions. Theoretically, this type of connection allows download speeds of up to 9 megabits per second and upload speeds of up to 640 kilobits per second. The difficult part in establishing an DSL circuit is that it must be configured to connect two specific locations, unlike a regular phone line or cable modem. DSL is often seen as a better alternative to the older ISDN standard.

E-Commerce- E-commerce (electronic-commerce) refers to business over the Internet. Web sites such as Amazon.com, Outpost.com, and eBay are all e-commerce sites. The two major forms of e-commerce are Business-to-Consumer (B2C) and Business-to-Business (B2B). While companies like Amazon.com cater mostly to consumers, other companies provide goods and services exclusively to other businesses. The terms "e-business" and "e-tailing" are often used synonymously with e-commerce. They refer to the same idea; they are just used to confuse people trying to learn computer terms.

E-Mail-  It's hard to remember what our lives were like without e-mail. Ranking up there with the Web as one of the most useful features of the Internet, e-mail has become one of today's standard means of communication. In fact, billions and billions of messages are sent each year. If you're like most people these days, you probably have more than one e-mail address. After all, the more addresses you have, the more sophisticated you look...
E-mail is part of the standard TCP/IP package of protocols. Sending messages is typically done by SMTP (Simple Mail Transfer Protocol) and receiving messages is handled by POP3 (Post Office Protocol 3), or IMAP (Internet Message Access Protocol). IMAP is the newer protocol, allowing you to view and sort messages on the mail server, without downloading them to your hard drive.
Though e-mail was originally developed for sending simple text messages, it has become more robust in the last few years. Now, HTML-based e-mail can use the same code as Web pages to incorporate formatted text, colors, and images into the message. Also, documents can be attached to e-mail messages, allowing files to be transferred via the e-mail protocol. However, since e-mail was originally not designed to handle large file transfers, transferring large documents (over 5 MB, for example) can cause problems. So remember to keep your attachments small!

Encryption-  This is the coding or scrambling of information in a file so that it can only be decoded and read by someone who has the correct decoding key. Encryption is commonly used in e-mail and other data transferring so that if someone were to intercept the message or data they would not be able to read it. So if you were sending a message over the office network to your co-worker about how much you hate your job, your boss, and the whole dang company, it would be a good idea to encrypt the message first.

Ethernet- Ethernet is the most common type of connection computers use in a local area network (LAN). The two most widely-used forms of Ethernet are called 10BaseT and 100BaseT. In a 10BaseT Ethernet, data transfer speeds can reach 10 mbps (megabits per second) through a copper cable. In a 100BaseT Ethernet, transfer speeds can get up to 100 mbps.  There is also a new technology called "Gigabit" Ethernet, employed by some of the latest Apple Power Macs, where data transfer rates peak at 1000 mbps.

FAQ- Stands for "Frequently Asked Questions," and is pronounced "F-A-Q". These text files, which are found all over the Internet, are created to answer the majority of questions a newcomer to a web site might have. Web sites will often refer visitors to the FAQ before telling them to e-mail their questions, which helps cut down on tech support. However, FAQs aren't just about web sites. There are thousands of FAQs out there for topics like company information, computer hardware, technology standards, and video games as well.

Firewall- A firewall is used to protect a networked server from damage by those who log in to it. This can either be a computer equipped with security features, software protection (called defensive coding), or both. A firewall allows only certain messages from the Internet to flow in and out of the internal network.

Flash- When you see the word "Flash" on the Web, it most likely refers to Macromedia's Web animation technology. By using Flash, Web developers can incorporate colorful animations with text, shapes, and images into their Web pages. Because the Flash technology is mainly vector-based, the animations typically don't take up a lot of disk space, which means a large animation can load relatively quickly. To view Flash content in your Web browser, you need to have the Flash plug-in. Fortunately, it comes standard with most browsers today. If you don't have the Flash plug-in, you can get it directly from Macromedia.

FTP- Stands for "File Transfer Protocol." It is a common and efficient method of transferring files via the Internet from one computer to another. Some common FTP programs are "Fetch", for the Mac, and "CuteFTP", for Windows.

Gateway- A gateway can be either hardware or software that acts as a bridge between two applications or networks so that data can be transferred between a number of computers. For example, when e-mail gets sent between two servers or when you log in to a web site, there is a gateway that allows the connection take place. In a completely unrelated story, Gateway is also the name of a popular direct-order PC manufacturer.

GIF- The letters "GIF" actually stand for "Graphics Interchange Format." GIFs are compressed graphics files and use a compression formula originally developed by CompuServe. GIFs you see on the Web use indexed color, or a palette of a certain number of colors (at most 256), which greatly helps reduce their file size. These compressed files can be quickly transmitted over a network or the Internet. GIF files are great for little icons and for animated images, but they lack the color range to be used for high-quality photos.

Gigabyte- A gigabyte consists of roughly 1 billion bytes. To be exact, there are 1024 megabytes or 1,073,741,824 bytes in a gigabyte, but no one really cares. Because of the large size of today's hard disks, storage capacity is usually measured in gigabytes. Abbreviation: "GB".

Home Page- The starting point, or main page of a web site. This page usually has some sort of table of contents on it and describes the purpose of the site.

Host- This is a computer that acts as a server for other computers on the network. It can be a web server, an e-mail server, an FTP server, etc. For instance, a web host is what provides the content of web pages to the computers that access it.

HTML- Stands for "Hyper-Text Markup Language." Today's software programs are created mostly in C/C++; today's web pages are created in HTML. Also known as hypertext documents, web pages must conform to the rules of the the HTML language in order to be displayed correctly in a web browser. The HTML syntax is based on a list of tags that describe the format and what is displayed on web pages.

HTTP:  Stands for "HyperText Transfer Protocol." It is the protocol used to transfer data over the World Wide Web. Yes, that's why all web site addresses begin with "http://". Whenever you type a URL into your browser and hit Enter, your computer sends an HTTP request to a Web server. The Web server then sends to you the requested HTML page.

Hub- A little device that is used to network multiple computers together. It is a central connection for all the computers in a network, which is usually Ethernet-based. Information sent to the hub can flow to any other computer on the network. So basically, if you're planning on connecting more than two computers together, go get a hub. If you only need to network two computers together, a simple crossover Ethernet cable will work and you don't even need a hub.

Icon- Icons are a visual representation of something on your computer. For example, a blue "e" on your screen most likely represents the Internet Explorer program. An icon that looks like a sheet of paper is likely a text document. By clicking and dragging icons, you can move the actual files they represent to various locations on your computer's hard drive. By double-clicking an application icon, you can open the program. Icons make computing much more user-friendly than having to enter text commands to accomplish anything. Some Unix nerds would beg to differ, but I'm talking about normal people here.

Internet- Believe it or not, the Internet was created in 1969, during the Cold War, by the United States military. It was meant to be a "nuke-proof" communications network. Today, it consists of countless networks and computers all over the world, allowing millions of people to share information. Information on the Internet is transferred on huge lines known collectively as the Internet backbone.
Many people think the Internet and the World Wide Web are the same thing. They're not. The World Wide Web is what you are browsing right now -- it is only part of the Internet.

Intranet- Contrary to popular belief, this is not simply a misspelling of "Internet". An Intranet is an internal or private Internet used strictly within the confines of a company, university, etc.
Up until the last few years, most corporations used networks composed of expensive proprietary hardware and software. Now, using basic Internet technology, intranets have made internal communication much easier and less expensive. Intranets use a TCP/IP connection, just like the average home Internet user does. The documents in an Intranet are also HTML-based, which is what allows them to be accessed using a web browser like Internet Explorer.

IP- Stands for "Internet Protocol." This is what allows for data to be transferred between systems over the Internet. It provides a standard set of rules for sending and receiving data via the Internet.

IP Address- Also known as an IP number, it is a code made up of numbers separated by 4 dots that identifies a particular computer on the Internet. Every computer, whether it be a web server or the computer you're using right now, requires an IP address to connect to the Internet.  If you have a standard dial-up account with an Internet Service Provider (ISP), you will either be assigned a static IP address (which is always the same), or you will be given a dynamic IP address, (which changes every time you log on). ISPs typically assign users a dynamic IP address each time they sign on because it cuts down on the number of IP addresses they must register. However, if you connect to the Internet through a network, it is very likely that you have a static IP address.
 

IRC- Stands for "Internet Relay Chat." IRC makes it possible for people using the Internet to converse with each other in real time by typing messages back and forth. For IRC to work, there needs to be an IRC server. When you and others connect to the server, you can join a channel and talk with the other people on the channel. Usually, channels have a specific topic like "teenchat", "macusers", or "basketweaving". To connect to an IRC server, you'll need a software program like Ircle (Mac) or mIRC (Windows). Most IRC programs also let you transfer files with other users.

ISDN- Stands for "Integrated Services Digital Network." ISDN is a data transfer technology, created in 1984, that allows for faster transfer rates than modems do. Basically, ISDN enables wide-bandwidth digital transmission over the public telephone network. Using ISDN, you can transfer 64K or 128K of data per second.

ISP- Stands for "Internet Service Provider." It's how just about all homes are connected to the Internet. Most ISPs are made up of a network of servers, including Web, e-mail, and news servers. When your modem dials your ISP, a point-to-point protocol (PPP) connection is established with another modem on the ISP's end. From there, you are connected to routers which route you to the Internet "backbone." From there, you can access stuff from anywhere around the world.

Java- Java is a computer programming language developed by Sun Microsystems. The syntax it uses is much like that of C/C++, but it's structured around classes instead of functions. It can also be used for programming applets -- small programs that can be embedded in web sites.

JavaScript- Like Java, this is a programming language designed by Sun Microsystems (in conjunction with Netscape) that can be integrated into standard HTML pages. It is based off the Java programming language, but is used mainly to create interactive web pages. Because of the usefulness of JavaScript, many professional web sites incorporate it in the HTML of their web pages to make them more dynamic and interactive.

JPEG- The term actually stands for "Joint Photographic Experts Group," because that is the name of the committee that developed the format. A JPEG is a compressed graphic file format. JPEG compression is much better for compressing graphics with photographic color depth than GIF compression is. So, if you see a really colorful image on the web, it is most likely in JPEG format. JPEGs are not limited to a palette of 256 colors like GIFs are, but JPEG is a "lossy" format, which means some quality is lost when the image is compressed. Like GIFs, JPEGs are cross-platform, meaning the same file can be viewed equally on both a Mac and PC.

Kbps- Stands for "Kilobits Per Second." Try not to confuse this with Kilobytes per second (which is 8 times more data per second). This term is most often used in describing modem speeds. For example, two common modem speeds are 33.6 Kbps and 56 Kbps.

Kilobyte- A kilobyte consists of 1024 bytes of computer data. ( "But 'kilo' means one thousand!" you exclaim. Right, but in the computer world, rules and guidelines don't really have the same influence as they do in most other cases. Just ask any computer programmer. However, because 1024 is so close to 1000, in most cases a kilobyte is rounded off to 1000 bytes. Common download speeds with a 56K modem are 3 to 5 kilobytes/sec. Abbreviation: "K".

LAN- Stands for "Local Area Network."  It's a computer network limited to a single building or small area. Most large office buildings today use LANs, making it easy for employees to share information. Currently, the most common type of LANs are Ethernet-based and use software from Novell or Oracle.

Link- When you're browsing the Web and you see a highlighted and underlined word or phrase on a page, there's a good chance you're looking at a link. These friendly little guys allow you to "jump" to another web site, another frame, or another part of the page you're currently viewing.

Linux- Pronounced "lihnuks", this is an operating system similar to Unix, created by Linus Torvalds. He freely distributed his OS, helping it to gain popularity. The current supported hardware platforms are Intel, PowerPC, DEC Alpha, Sun Sparc, and Motorola.

Login- Unlike the words "brush", "comb", and "e-mail", this term should not be used as both a noun and a verb. It should only be used as a noun, (You don't login to a server, you log in to it) and it refers to a username, or a code that identifies you to a certain server. It is often used in conjunction with a password to verify who is accessing the server. For example, when trying to access some forbidden top secret documents, you'll often encounter a screen that says, "Please enter your login and password."