Glossary of Terms
ActiveX
This set of technologies from Microsoft provides tools for linking desktop applications to the World Wide Web. Using a variety of programming tools—including Java, Visual Basic, and C++--developers can create interactive Web content. For instance, ActiveX technology can allow users to view Word and Excel documents directly in a browser.
AIFF
Audio Interchange File Format. This audio file format was developed by Apple Computer for storing high-quality sampled audio and musical instrument information. It is also used by Silicon Graphics and in several professional audio packages. Played by a variety of download able software on both the PC and the Mac.
Anonymous FTP
This is a method of file transfer that allows you to log in to an ftp server as an unregistered user. When you log in to an anonymous ftp site, you’re prompted for a login name and password and you have to enter the word anonymous as your login name and enter your email address as a password.
ANSI
American National Standards Institute. This organization of American industry groups works with the standards committees of other nations to develop standards to facilitate international trade and telecommunications. Some of ANSI’s greatest hits in the computing field include ASCII, SCSI, and the ANSI.SYS device driver.
Anti-Aliasing
On computer monitors the pixels themselves aren’t curved, but they have to show curves. Using polygons to simulate curves in alphanumeric characters or vector graphics makes the edges of objects appear jagged. The technique for smoothing out these jaggies is called anti-aliasing, and it usually takes the form of throwing in pixels of washed-out color along the curve. This actually makes text seem a little blurred but, strangely enough, more readable.
API
Application Programming Interface. An API is a series of functions that programs can use to make the operating system do their dirty work. Using Windows APIs, for example, a program can open windows, files, and message boxes—as well as perform more complicated tasks—by passing a single instruction. Windows has several classes of APIs that deal with telephony, messaging, and other issues.
Applet
Applet is a diminutive form of app (application), and it refers to simple, single-function programs that often ship with a larger product. Programs such as Windows’ Calculator, File Manager, and Notepad are examples of applets.
Archie
A long-established (read: antiquated) way to find files on the Internet, Archie is a system that gathers, indexes, and helps you find information anywhere on the Internet. Developed at McGill University, Archie started life as an indexed directory of files from archives. However, Archie is a slow boy, and his findings depend on how well maintained the Archie server he connects to is. Found files are retrieved using ftp (file transfer protocol).
ASCII
American Standard Code for Information Interchange Bland, unformatted text files are best saved in ASCII (pronounced “askee”) format. But ASCII is more than a text file format—it’s a standard developed by the American National Standards Institute (ANSI) to define how computers write and read characters. The ASCII set of 128 characters includes letters, numbers, punctuation, and control codes (such as a character that marks the end of a line). Each letter or other character is represented by a number: an uppercase A, for example, is the number 65, and a lowercase z is the number 122. Most operating systems use the ASCII standard, except for Windows NT, which uses the suitably larger and newer Unicode standard.
Asynchronous Communication
This term describes how your computer uses a modem to connect with other computers. Back in the days of teletypes and dumb terminals, computers sent data synchronously—they operated using a shared timer that marked the transmission of each character. This didn’t work very efficiently for large blocks of data over phone lines, however. So modern modems use asynchronous rules: instead of synching up to a time signal to mark a character, transmitting computers use a start bit, a stop bit, and an optional error-checking parity bit to indicate to receiving computers the boundary of each character. (The term is a bit of a misnomer, though, since all modems synch up with one another before they transmit data.)
ATM
Asynchronous Transfer Mode. This standard packet-switching protocol for transmitting and receiving data uses uniform 53-byte cells. (Each cell has a 5-byte address header and 48 bytes of data.) These short, standardized cells can be processed through a digital ATM switch very quickly, allowing for data transmission speeds surpassing 600 mbps. ATM was designed to support multiple services, including voice, graphics, data, and full-motion video. It also allows telephone and cable TV companies to dynamically assign bandwidth to individual customers.
Authentication
Authentication ensures that digital data transmissions are delivered to the intended receiver. Authentication also assures the receiver of the integrity of the message and its source (where or whom it came from). The simplest form of authentication requires a user name and password to gain access to a particular account. But authentication protocols can also be based on secret-key encryption, such as DES, or on public-key systems using digital signatures.
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Bandwidth
In a general sense, this term describes information-carrying capacity. It can apply to telephone or network wiring as well as system buses, radio frequency signals, and monitors. On a more human level, the term can describe a person’s capacity for dealing with multiple projects (“I’d like to update this database, but I don’t have the bandwidth.”). Bandwidth is most accurately measured in cycles per second, or hertz (Hz), which is the difference between the lowest and highest frequencies transmitted. But it’s also common to use bits or bytes per second instead.
Baud
Most people use baud to describe modem speeds in bits per second—but they’re wrong. They may say a 9,600-bps modem transmits at 9,600 baud, but really baud is a measure of how frequently sound changes on a phone line. Modern modems transmit more bits with fewer changes in sound, so baud and bps numbers aren’t equal. However, only editors, pedants, and communications engineers now care about the distinction. But if you run into members of these groups, use bps instead of baud.
BIOS
Basic Input/Output System. The BIOS is what’s coded into a PC’s ROM to provide the basic instructions for controlling system hardware. The operating system and application programs both directly access BIOS routines to provide better compatibility for such functions as screen display. Some makers of add-in boards such as graphics accelerator cards provide their own BIOS modules that work in conjunction with (or replace) the BIOS on the system’s motherboard.
Bit
Binary digit. A bit is the smallest unit of data in computing, with a value of either 0 or 1. Whenever you see a lowercase b associated with a number, it’s likely to be a bit. It can be prefixed with kilo-(for 1,024 bits, or 2 to the 10th power) or mega-(1,024 x 1,024 bits)—and sometimes finds its way into data transfer speeds (such as 14.4 kbps).
Bitmap
Any picture you see on the Web (or hot off a scanner, or on a page created with a desktop publishing application) is called a bitmap. As its name suggests, a bitmap is a map of dots—similar to what you see when you look at a newspaper photo under a strong magnifying glass—that looks like a picture when viewed from a distance. Bitmaps come in many file formats (GIF, JPEG, TIFF, BMP, PICT, and PCX, to name a few) and can be read by paint programs and image editors such as Adobe Potoshop. If you zoom in on or try to scale up a bitmap, it will look blocky. Digital pictures that you can easily scale up (such as those created in PostScript, CorelDraw, or CAD formats) are called vector graphics.
Boolean
English mathematician George Boole (1815-64) founded a field of mathematical and philosophical study called symbolic logic. His name is now used most often to describe a subset of symbolic logic: constructing database queries. Whenever you see a Web search tool or database query system that allows you to use AND, OR, and NOT to hone your search, the chances are it uses Boolean techniques. The most common Boolean operators are AND (you’re looking for all terms), OR (you’re looking for at least one of the terms), and NOT (you’re excluding a term). You’ll always see the operators referred to in uppercase letters, although you usually don’t need to enter them that way to make a Boolean search work properly. Also, the Boolean operator AND doesn’t work like a normal English and. For example, a Boolean search through a database of rock musicians for members of the Beatles AND Wings would turn up only Paul McCartney. For details on how to construct Boolean queries, read CNET’s Boolean search primer.
BPS
Bits Per Second. Your modem’s speed is measured by the number of bits it can transfer in a second. If your modem is rated at 9,600 bps or less, you’re behind the times. Modems rated in kilobits per second now rule: 14.4 kbps is the minimum acceptable, and 28.8 kbps is the premium modem speed.
Browser
If you can read this, it’s highly likely that you’re using a Web browser. In brief, a browser is your interface to the World Wide Web; it interprets hypertext links and lets you view sites and navigate from one Internet node to another. Among the companies that produce browsers are NCSA Mosaic, Netscape, and Microsoft, as well as commercial services like CompuServe, Prodigy, and America Online.
Byte
A byte usually denotes 8 bits (also called an octet or a word), which the computer treats as a single unit. Longer sequences like 16 and 32 bits are also possible. Abbreviated as uppercase B.
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Cache
Caches come in many types, but they all work the same way: they store information where you can get to it fast. A Web browser cache stores the pages, graphics, sounds, and URLs of online places you visit on your hard drive; that way, when you go back to the page, everything doesn’t have to be downloaded all over again. Since disk access is much faster than Internet access, this speeds things up. Of course, disk access is slower than RAM access, so there’s also disk caching, which stores information you might need from your hard disk in faster RAM.
CD-ROM
Compact Disc, read-only memory. A compact disc used to store and play back computer data instead of digital audio. CD-ROMs can contain up to 650MB of data (though they often contain a lot less). CD-ROMs have become a favorite medium for installing programs, since they cost only slightly more to manufacture than floppy disks, and most major software applications come on at least five floppies. Don’t sound hopelessly out of touch with technology: use the term CD-ROM to refer to the technology or the discs, but not to the hardware you play the discs on. That’s a CD-ROM drive.
CGI
Common Gateway Interface. The CGI standard lays down the rules for running external programs in a Web HTTP server. External programs are called gateways because they open up an outside world of information to the server.
CGI-bin
CGI binary. When you see this directory in your Web browser’s URL window, it’s a sign that you’re running a CGI program, such as a search tool.
CHAP
Challenge-Handshake Authentication Protocol. One of the two main authentication protocols used to verify a user’s name and password for PPP Internet connections. CHAP is more secure than PAP because it performs a three-way handshake during the initial link establishment between the home and remote machines. It can also repeat the authentication anytime after the link has been established.
Client
The customer side of a client/server setup. To confuse matters, when you log on to a server, the word client can refer to you, to your computer, or to the software running on your computer. For example, to download something from an ftp site, you use ftp client software.
COM port
Although it’s in all capital letters, COM is not an acronym. It’s a contraction of communications, and it’s used to describe the serial port on a PC. COM is generally used in conjunction with a number, as in COM1, COM2, COM3, or COM4.
Cookie
When you need to pass some snippet of information to another system to make it do something, how do you do it? If you’re on the Web or some other network, you use a cookie (also known as a magic cookie). The cookie is a text file saved in your browser’s directory or folder and stored in RAM while your browser is running. Most of the information in a cookie is pretty mundane stuff, but some Web sites use cookies to store personal preferences. (SEARCH.COM, MSN, and Netscape all have personalization processes that use cookies to store information). If you want to see what information is stored in your cookie file, use a text editor or a word processor to open a file called cookie.txt or MagicCookie in your browser’s folder or directory.
CPU
Central Processing Unit. Look for the most powerful microprocessor chip in your computer, and that’ll be the CPU. The Intel Pentium and Motorola 68040 chips, for example, handle the central management functions of a high-powered PC and Mac, respectively. Sometimes the term CPU is used to describe the whole box that contains the chip (along with the motherboard, expansion cards, disk drives, power supply, and so on). Both uses are widespread, but only the first is really accurate.
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Daemon
Pronounced “demon,” this Unix term refers to a specific type of program or agent designed to work in the background. Using a daemon, a program can simply hand off data to the smaller program and go on to more important things. For example, a print daemon could handle print requests from multiple users and applications, freeing them for other tasks.
DLL
Dynamic Link Library. When you’re trying to share functions or resources among Windows programs, you generally put them in DLLs. These libraries do all kinds of things, from holding icons (Windows 3.1’s moricons.dll) to enabling Visual Basic programs (vbrun3.dll) to creating network sockets that allow you to hook up to the Internet (winsock.dll).
Device Independence
When you’re developing a program, especially a game or multimedia title, the toughest element to deal with is the hardware that will run it. Complex animation, color-rich graphics, and video and sound can all clog up or choke because of conflicting hardware standards. Device independence is the developer’s ideal: you develop your application and let the operating system and its device drivers figure out how to make the hardware handle it. At the very least, device independence requires hardware standards such as VGA and decent drivers. APIs and hardware abstraction layer standards are a more robust approach todevice independence.
DNS
Domain Name System. When you send email or point a browser to an Internet domain such as cnet.com, the domain name system translates the names into Internet addresses (a series of numbers looking something like this: 123.123.23.2). The term refers to two things: the conventions for naming hosts and the way the names are handled across the Internet.
Domain Name
Looking for a domain name? You’ll find it to the right of the @ sign in an email address, or about ten characters into a URL. CNET’s domain name is cnet.com. The domain name of daemous@pentagon.io.com is io.com. Domain names are issued by the National Science Foundation (NSF), and they come with different extensions based on whether the domain belongs to a commercial enterprise (.com), an educational establishment (.edu), a government body (.gov), the military (.mil), a network (.net), or a nonprofit organization (.org). Some domains use a geographical notation too (such as the San Francisco, California-based well.sf.ca.us).
Duplex
If you have a printer that can print on both sides of a sheet of paper, it’s duplex. If you have a communications line that lets you send and receive data (or talk and listen) at the same time, it’s duplex. If you use a cheap speakerphone, you’ll notice that as soon as it picks up any noise at your end, it cuts off whatever was being said by the person on the other end. That speakerphone is not duplex.
DVD
Digital Versatile Disc. These high-capacity optical discs are capable of storing everything from massive computer applications to full-length movies. While similar in physical size and appearance to a compact disc or a CD-ROM, DVD is a huge leap from its predecessor’s 650MB of storage. A standard single-layer, single-sided DVD disc can store a whopping 4.7GB of data. But it doesn’t stop there—DVD also has a two-layer standard that boosts the single-sided capacity to 8.5GB. And there’s more! DVD discs can be double-sided, ramping up the maximum storage on a single disc to 17GB. Unfortunately, to use DVD discs, you’ll have to buy a new drive, but that new hardware will also read your older CD-ROMs and audio CDs.
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Encryption
Encryption is the process of changing data into a form that can be read only by the intended receiver. To decipher the message, the receiver of the encrypted data must have the proper decryption key. In traditional encryption schemes, the sender and the receiver use the same key to encrypt and decrypt data. Public-key encryption schemes use two keys: a public key, which anyone may use, and a corresponding private key, which is possessed only by the person who created it. With this method, anyone may send a message encrypted with the owner’s public key, but only the owner has the private key necessary to decrypt it. PGP (Pretty Good Privacy) and DES (data encryption standard) are two of the most popular public-key encryption schemes.
Ethernet
Ethernet is a standard for connecting computers into a local area network (LAN). The most common form of Ethernet is called 10BaseT, which denotes a peak transmission speed of 10 mbps using copper twisted-pair cable.
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FAQ
Frequently Asked Questions. These text files are supposed to answer all the questions a newcomer to an online site might have. Designed to cut down on basic tech support queries, FAQ can be organized in virtually any structure, and they often cover a far wider range of subjects than just basic site orientation. You can either pronounce it “facks” or sound out each letter.
Fast Ethernet
Fast Ethernet is an upgraded standard for connecting computers into a local area network (LAN). It works just like regular Ethernet except that it can transfer data at a peak rate of 100 mbps. Also referred to as 100BaseT, fast Ethernet is more expensive and less common than its slower 10BaseT sibling.
Fat Binary
When you see a download or another program labeled “fat binary,” it means that the program is a little larger than a regular app. The reason? A fat binary program can take full advantage of two hardware platforms: the Macintosh and the Power Mac.
Fiber-Optic Cable
Fiber-optic cables consist of thin filaments of glass (or other transparent materials), which can carry beams of light. A laser transmitter encodes frequency signals into pulses of light and sends them down the optical fiber to a receiver, which translates the light signals back into frequencies. Less susceptible to noise and interference than other kinds of cables, optical fibers can transmit data greater distances without amplification. But because the glass filaments are fragile, optical fiber must be run underground rather than overhead on telephone poles.
Finger
Finger is a program that you point at the user name of someone on a networked system. It uncovers that person’s full name, most recent log-in time, and other information. It’s also used as a verb, meaning to apply the program to a user name.
Firewall
If you want to protect any networked server from damage (intentional or otherwise) by those who log in to it, you put up a firewall. This could be a dedicated computer equipped with security measures such as a dial-back feature, or it could be software-based protection called defensive coding.
FPU
Floating-Point Unit. Your computer’s CPU is geared toward dealing with integer mathematics. When you throw floating-point math at it, the CPU shucks off the responsibility to the FPU (if the computer has one), which is designed to handle floating-point math more efficiently. Once called a numeric (or math) coprocessor, the FPU can be either a separate chip (such as Intel’s 80387 or Motorola’s 68881), or it can be integrated into the CPU, such as the Pentium or 68040 processors. Just as 1994’s flawed Pentiums could be induced to perform floating-point operations (by running a program to disable the FPU), your CPU can, too—but it won’t do it as quickly as an FPU.
Freeware
Freeware is a class of software that you can download, pass around, and distribute without payment. However, it’s still copyrighted, so you can’t turn around and decompile it or sell it as your own (as you can with a public domain program). Freeware was originally a trademark of Andrew Fluegelman, the founder of shareware, but ironically the word has passed into the public domain.
FTP
File Transfer Protocol. This Internet protocol is used to copy files between computers—usually a client and an archive site. It’s old-fashioned, it’s a bit on the slow side, it doesn’t support compression, and it uses cryptic Unix command parameters. But the good news is that you can download shareware or freeware apps that shield you from the complexities of Unix, and you can connect to ftp sites using a Web browser.
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Gateway
A gateway is a program or piece of hardware that passes data between networks. You’ll see this term most often when you either log in to an Internet site or when you’re passing email between different servers.
GIF
Graphics Interchange Format. Almost every color graphic image and background you see on the Web is likely to be a GIF file. This compact format is ideal for graphics that use only a few colors, and it was once the most popular file format for online color photos. However, GIF is losing some ground to JPEG in the online photo stakes: while GIF images are limited to 256 colors, JPEG files can look almost as good as photographs and can contain up to 16 million colors. GIF files can be viewed using a variety of download able software on both the PC and the Mac.
Gigabyte
This year’s minimum hard disk size is one gigabyte, or 1,073,741,824 bytes, which should be enough for Windows 95 and other modern operating systems—for a few months at least. Abbreviated as GB.
Gopher
Named after a college mascot--and for its ability to “go for” information—Gopher is a text-based information retrieval system for the Internet. Equipped with a Gopher client, you can use Gopher servers to search databases around the globe for keywords or subjects. Because Web browsers include Gopher client capabilities, the Web is superseding Gopher for document retrieval. One advantage of searching with Gopher is that you can read stuff directly from the servers—no need to copy or save the files to your system first.
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Handshake
You want some data? I’ll transmit it to your machine. If it’s coming in too fast, you tell me to wait so you can catch up. The protocol for doing this is called a handshake, and it usually takes place over a pair of wires on the serial port’s RS-232 interface. The computer uses one of the wires to stop or start the transfer of data from the modem, and the modem uses the other wire to start or stop transfer from the computer. The wires used are called CTS and RTS.
Half Duplex
Twenty years ago, modem communication was either asynchronous full duplex (one character at a time sent in both directions at once) or synchronous half duplex (a block of characters at a time, but sent in only one direction). These days, modems are all synchronous half duplex. Why? Because it’s more efficient: at 28.8 kbps, 2 modems can send and receive 25 packets of data every second. That looks like duplex transfer to a casual observer, but if you’re counting in milliseconds, the duplex is only half full.
Helper Applications
The only type of media a Web browser absolutely has to handle is hypertext. Graphics, sounds, and multimedia are luxuries that many browsers shuck off to helper applications. The big advantage to using helper apps is that you can add them to the MIME standard to cover new file types as they come along and upgrade to more capable viewers for existing file types without changing your browser. Sometimes called a viewer.
Home Page
Web sites are by nature tangled groups of interconnected pages. To make them easier to navigate, the sites have one or more home pages that you can use for orientation. A home page serves as the site’s introduction, starting point, and guide.
HTML
Hypertext Markup Language. As its name suggests, HTML is a collection of formatting commands that create hypertext documents—Web pages, to be exact. When you point your Web browser to a URL, the browser interprets the HTML commands embedded in the page and uses them to format the page’s text and graphic elements. HTML commands cover many types of text formatting (bold and italic text, lists, headline fonts in various sizes, and so on), and also have the ability to include graphics and other non text elements. Development and maintenance of HTML standards is coordinated by the World Wide Web Consortium.
HTTP
Hypertext Transfer Protocol. At the beginning of every URL, you see these four letters. They tell the Web server how your browser intends to communicate with it. (Two computers need to establish a communications protocol right away, or they’ll never get around to exchanging data.) When you connect to a World Wide Web server, both systems use this protocol to transfer the document from the server to your system.
Hub
This chunk of hardware is used to network computers together (usually over an Ethernet connection). It serves as a common wiring point so that information can flow through one central location to any other computer on the network.
Hypermedia
One step ahead of hypertext, hypermedia integrates text, images, video, and sound into its documents. The elements of hypermedia documents are linked in an interactive way. The best way to describe hypermedia is by example—and the most common examples are the sound-laden pages of the World Wide Web.
Hypertext
Hypertext is a nonsequential way of presenting information. Hypertext links information in a complex web of associations, powered by hyperlinks. Essentially a way of browsing information, hypertext is a way to describe how you learn information from a well-designed CD-ROM encyclopedia or from the World Wide Web.
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Interlaced
When you watch television, you’re looking at an interlaced video display. On TVs as on computer monitors, the whole screen is drawn line by line. But because early television tubes couldn’t draw the whole screen before the top began to fade, TV engineers implemented a system called interlacing, which skips every second line on the first pass and fills in those lines on a second pass. This system might result in a little flicker, but it avoids having the bottom of the screen perpetually brighter than the top. It also gets away with refreshing the screen half as often. Most normal-resolution PC and Mac monitors aren’t interlaced, but lower-quality display adapters pushed into high resolutions and high color sometimes do interlace. It’s not a pretty sight up close, however. Avoid it when you can.
Intranet
A play on the word Internet, an intranet is a restricted-access network that works like the Web, but isn’t on it. Usually owned and managed by a corporation, an intranet enables a company to share its resources with its employees without confidential information being made available to everyone with Internet access.
IP
Internet Protocol. The Internet protocol defines how information gets passed between systems across the Internet.
IP Address
Internet Protocol address. This address is a unique string of numbers that identifies a computer on the Internet. These numbers are usually shown in groups separated by periods, like this: 123.123.23.2. All resources on the Internet must have an IP address--or else they’re not on the Internet at all.
IPX
Internetwork Packet Exchange. NetWare’s network-layer protocol handles networking addressing, routing, and packets. The most common of all networking protocols, IPX loads when you log on to a network.
IRC
Internet Relay Chat. IRC is a way of hooking up with other Net users to exchange written comments—live and in real time. To do this, you need an IRC client and an IRC server. Once connected to the server, you join a channel, or discussion group, which can include people from all over the world. IRC channels may hold discussions about anything under the sun (and some topics that shouldn’t see the light of day). IRC can be accessed by a variety of download able software on both the PC and Mac.
ISDN
Integrated Services Digital Network. The plain old telephone system doesn’t handle large quantities of data, and the phone companies realized this a long time ago. So the ISDN spec was hammered out in 1984 to allow for wide-bandwidth digital transmission using the public switched telephone network. Under ISDN, a phone call can transfer 64 kilobits of digital data per second. But it’s not always easy to adopt.
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Java
Sun Microsystems’ Java is a programming language for adding animation and other action to Web sites. The small applications (called applets) that Java creates can play back on any graphical system that’s Web-ready, but your Web browser has to be Java-capable for you to see it. According to Sun’s description, Java is a “simple, object-oriented, distributed, interpreted, robust, secure, architecture-neutral, portable, high-performance, multithreaded, dynamic, buzzword-compliant, general-purpose programming language.” And Sun should know.
JPEG
Joint Photographic Experts Group. This file format for color-rich images was developed by the Joint Photographic Experts Group committee. JPEG compresses graphics of photographic color depth better than competing file formats like GIF, and it retains a high degree of color fidelity. This makes JPEG files smaller and therefore quicker to download. You can choose how much to compress a JPEG file, but since it is a lossy format, the smaller you compress the file, the more color information will be lost. JEPG files can be viewed by a variety of download able software on both the PC and Mac.
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Kermit
This is a protocol for transferring files during direct dial-up communications that’s named after a Muppet (seriously). Kermit is sound but old and can be very slow--slower than Xmodem, Ymodem, and much slower than Zmodem.
Kilobyte
Although kilo is Greek for a thousand, a kilobyte actually contains 1,024 bytes (that’s 2 to the 10th power). In other words, a thousand bytes is actually less than a kilobyte. Remember that the next time you download a file. Abbreviated as K.
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LAN
Local Area Network. A local area network is a short-distance network used to link a group of computers together within a building. 10BaseT ethernet is the most commonly used form of LAN. A piece of hardware called a hub serves as the common wiring point, enabling data to be sent from one machine to another over the network. LANs are typically limited to distances of less than 500 meters and provide low-cost, high-bandwidth networking capabilities within a small geographical area.
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Megabyte
Although mega is Greek for a million, a megabyte actually contains 1,048,576 bytes (1,024 x 1,024 bytes). In other words, a million bytes is actually less than a megabyte. Remember that the next time you buy a hard disk or try to fit files onto a floppy disk. Abbreviated as MB.
MFLOPS
Mega-Floating Point Operations Per Second. Used as a measure of how powerful your computer is, MFLOPS gauge the capability of your system to deal with floating-point math instead of raw instructions.
MIDI
Musical Instrument Digital Interface. Pronounced “middy,” this connectivity standard enables you to hook together computers, musical instruments, and synthesizers to make and orchestrate digital sound. The term is used to describe the standard itself, the hardware that supports the standard, and files that store information that the hardware can use. MIDI files are like digital sheet music—they contain instructions for musical notes, tempo, and instrumentation—and are widely used in game soundtracks and recording studios.
MIME
Multipurpose Internet Mail Extensions. MIME has absolutely nothing to do with Marcel Marceau. It’s a way to extend the power of Web browsers to handle graphics, sound, multimedia—anything but text. (Remember, HTML handles nothing but text—everything else is an extension.) MIME is also used for binary email attachments. Browsers recognize MIME types in categories and file types, separated by a slash (such as image/gif). If you’ve registered a MIME type, the browser decodes the file and launches a helper application.
MIPS
Millions of Instructions Per Second. Used as a measure of how powerful your computer is, MIPS gauge the capability of your system to handle instructions.
Mirror Site
Because the Internet population has exploded in recent years, a lot of archive servers can’t cope with the load. One solution is to create an exact copy of a server--a process called mirroring. Mirror sites divert some of the traffic from the original site. It’s not unusual to find a dozen or more mirrors of busy ftp sites.
Modem
A modem is an external box or internal circuitry that converts computer data into sound that can be transmitted over phone lines. First used to send telegrams, early modems alternated between two different tones. This is called modulation, and the process of modulating (and demodulating at the receiving end) gave the modem its name. These days modems transmit data with lots of different tones, signals, and complex mathematical processing, so modem is a bit of a misnomer.
Motherboard
Every system has one: The motherboard is the largest printed circuit board in your computer. It generally houses the CPU chip, the controller circuitry, the bus, and sockets for additional boards, which are called daughterboards. If you have a horizontal-style computer, the motherboard is generally the one at the bottom of the computer’s box. If you have a ower-configuration box, it’s along one of the vertical sides.
MPEG
Moving Pictures Experts Group. MPEG is a standard for compressing sound and movie files into an attractive format for downloading—or even streaming—across the Internet. The MPEG-1 standard streams video and sound data at 150 kilobytes per second (kBps)—the same rate as a single-speed CD-ROM drive—which it manages by taking key frames of video and filling only the areas that change between the frames. MPEG files are usually smaller than QuickTime or Video for Windows files, though the quality isn’t always as good. Popular MPEG players include MPEGPlay and VMPEG for Windows and Sparkle for the Mac.
MUD
Multiple-User Dimension. Originally known as a Multi-User Dungeon, a MUD is a text-based virtual environment in which users’ “characters” interact in real time. Characters can navigate rooms described by text; type to other characters; create shared objects; and engage in games, puzzles, or combat. Most MUDs involve some level of role-playing, where characters adopt personas from books or medieval times, for example. A MUD can be accessed via Telnet or using a special MUD client.
Multicasting
When you send out data (like television or radio programming) to anyone who cares to tune in, it’s broadcasting. When you send out data (such as your voice on a Web phone) to a few receivers you’ve identified and selected, it’s calledmulticasting.
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NetWare
Created by Novell to run on Intel-based computers, NetWare is the most widely used network operating system on that platform.
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OCR
Optical Character Recognition. When your computer gets a fax or scans in text, all it sees are graphical bits on a virtual page. That text is not usable, searchable, or editable. If you pass the page through an OCR program, the software converts the shapes on it into a text document. However, few documents are perfectly recognized and the errors are frequent if the type is small or the scan unclear. But the conversion is often faster than typing text manually.
Optical fiber
Optical fiber cables consist of thin filaments of glass (or other transparent materials), which can carry beams of light. A laser transmitter encodes frequency signals into pulses of light and sends them down the optical fiber to a receiver, which translates the light signals back into frequencies. Less susceptible to noise and interference than other kinds of cables, optical fibers can transmit data greater distances without amplification. But because the glass filaments are fragile, optical fiber must be run underground rather than overhead on telephone poles.
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PAP
Password Authentication Protocol. If you want to verify a user’s name and password for PPP Internet connections, you have two choices: PAP and CHAP. PAP is not as secure as CHAP, since it works only to establish the initial link. PAP is also more vulnerable to attack because it sends authentication packets throughout the network. Nevertheless, PAP is more commonly used than CHAP to log in to a remote host like an Internet service provider.
Parity
This is an obsolete method of detecting communication errors. These days, communication ports are almost always set to No Parity, and the modem’s internal error detection and correction are used to provide reliable communication.
Perl
Practical Extraction and Report Language. The programming language of choice for writing Web server applications, Perl is used for creating interactive forms and a slew of other CGI programs. This free-licensed language comes in versions for Windows NT, Novell NetWare, and Unix. Perl scripts are available free of charge all over the Internet. Pixel picture element The image displayed on monitors or in a graphic produced by a scanner or paint program is made up lots of dots called pixels. Collectively, the number of pixels displayed is referred to as the image’s resolution. A pixel on a monitor is a number of red, green, and blue phosphor dots. These dots are “excited” to varying degrees by the monitor’s three electron guns, and the results mix additively to generate a specific color. By manipulating large numbers of pixels in precise ways, patterns emerge to make up an identifiable picture.
Plug-In
This term refers to a type of program that tightly integrates with a larger application to add a special capability to it. The larger app must be designed to accept plug-ins, and the software’s maker usually publishes a design specification that enables people to write plug-ins for it. Two notable applications designed around a plug-in architecture are Adobe Photoshop and Netscape Navigator. Notable examples of plug-ins are Kai’s Power Tools for Photoshop and Shockwave for Netscape Navigator.
POP
Post Office Protocol. The current champ in Internet email mailbox access standards, but its limitations—basically, you connect to a server and download all your messages, which are then deleted from the server—discourage flexibility. Of course, some clients let you leave all messages on the server, and/or refuse to download messages above a certain size. Still, as messages become longer—with multimedia (such as sound or video) objects and the likes—we’ll want some flexibility in what we retrieve and when we retrieve it. That’s where IMAP comes in. The current version of POP is POP3.
PPP
Point-to-Point Protocol. PPP is the Internet standard for serial communications. Newer and better than its predecessor, SLIP, PPP defines how your modem connection exchanges data packets with other systems on the Internet.
Protocol
Computers can’t just throw data at each other any old way. Because so many different types of computers and operating systems connect via modems or other connections, they have to follow communications rules called protocols. The Internet is a very heterogeneous collection of networked computers and is full of different protocols, including PPP, TCP/IP, SLIP, and ftp.
Proxy Servers
A proxy server is a system that caches items from other servers to speed up access. On the Web, a proxy first attempts to find data locally, and if it’s not there, fetches it from the remote server where the data resides permanently.
Public Domain
Of all the kinds of software or information you can download, public domain has the fewest strings attached. With shareware, you’re expected to pay a fee. With freeware, you may face other restrictions, and there’s still a copyright attached. With public domain downloads (also called downloads in the pubic domain), there are no copyright restrictions whatsoever.
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QuickTime
Developed by Apple Computer, QuickTime is a method of storing sound, graphics, and movie files. If you see a .mov file on the Web or on a CD-ROM, you’ll know it’s a QuickTime file. And although QuickTime was originally developed for the Macintosh, QuickTime player software is now available for Windows and other platforms. If you don’t have a QuickTime player, you can always download versions for either the Mac or PC from Apple’s Web site.
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RAM
Random Access Memory. Your computer should have as much RAM as you can afford if it’s going to work efficiently. All computers use RAM in the same way (because they’re all based on the von Neumann architecture). Both programs and data are called up from permanent storage (usually a hard drive or floppy disk) and operate in RAM. In general, this means that the more RAM you have, the more able you are to handle large amounts of data and big programs—though in practice, a lot of data in RAM is passed off into slower virtual memory to free up working space.
Resolution
Resolution is a measure of graphics that’s used to describe what a printer can print, a scanner can scan, and a monitor can display. In printers and scanners, resolution is measured in dots per inch (dpi)—the number of pixels a device can fit in an inch of space. A monitor’s resolution refers to the number of pixels in the whole image, because the number of dots per inch varies depending on the screen’s dimensions. For example, a resolution of 1,280 by 1,024 means that 1,024 lines are drawn from the top to the bottom of the screen, and each of these lines is made up of 1,280 separate pixels—and in turn, each dot may have any number of combinations of red, green, and blue intensities. Common resolutions in the PC world include 640 by 480 (also called VGA resolution; appropriate for a 14-inch monitor), 800 by 600 (appropriate for a 15-inch monitor), 1,024 by 768 (appropriate for a 17-inch monitor), and 1,280 by 1,024.
RJ-11
This is the standard telephone connector—a tab snaps into the socket and has to be pressed to remove the connector from the wall. An ordinary phone circuit uses two wires. The RJ-11 jack has room for up to four wires, but at a glance it’s easy to mistake with the larger RJ-45 jack, which can house up to eight wires.
RJ-45
Looking a bit like a standard phone connector, an RJ-45 connector is twice as wide (with eight wires) and is used for hooking up computers to local area networks (LANs) or phones with lots of lines.
ROM
Read-Only Memory. ROM is a storage chip that typically contains hardwired instructions for use when a computer starts (boots up). The instructions—contained in a small program called the BIOS (basic input/output system)—loads from ROM and starts up the hard disk so that the operating system (OS) can be loaded and the whole shooting match can begin. Some ROM chips can be updated with new BIOS instructions—but unless you hear them called EEPROMs or flash BIOSs, the likelihood is, they can’t be.
Router
This piece of hardware does what it says: it routes data from a local area network (LAN) to a phone line’s long distance line. Routers also act as traffic cops, allowing only authorized machines to transmit data into the local network so that private information can remain secure. In addition to supporting these dial-in and leased connections, routers also handle errors, keep network usage statistics, and handle security issues.
RS-232
Recommended Standard 232. This was originally a nine-wire interface standard for teletype machines from the Electronics Industry Association. Now in its third revision (RS-232-C), it’s the standard for computer serial-port transfers. The RS-232 standard is probably the only computer component that’s 40 years old and still working. One wire is used as the ground; the rest are dedicated to detecting carrier signals, managing the timing of data transfer, oh, and sending and receiving data.
RTF
Rich Text Format. This file format, developed by Microsoft, enables you to save text files in your word processor with formatting, font information, text color, and some page layout information intact. Sure, saving a WordPerfect file in WordPerfect format does the same thing, but this format is intended for exchange among all kinds of word processors.
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SCSI
Small Computer System Interface. While the PC was settling for rankly inferior alternatives, the Mac adopted SCSI as its expansion standard. With SCSI, you can add up to seven new devices to your computer and depend on them to deal with single-interface issues by themselves. It’s a robust standard, and it’s rendered even more so with its latest implementation, SCSI-2. But it requires some system overhead, slows down your computer’s start-up, and demands that during installation you handle device ID administration and a process called termination that closes the SCSI circuit. Pronounced “scuzzy” by those in the know.
Semiconductor
A class of materials that allow electrical current to flow through them under certain conditions. Semiconductors are used to create common electronic components, such as diodes and transistors.
Serial Port
This is the communications port on your computer; it’s also called the COM or RS-232 port. It’s called serial because, although it has nine pins and many wires, the PC sends data on only one wire and receives data on one other wire. All the data bits have to follow one another on the single wire, as opposed to the parallel port, where eight separate wires transfer each bit of a byte.
Server
The business end of a client/server setup, a server is usually a computer that provides the information, files, Web pages, and other services to the client that logs on to it. (The word server is also used to describe the software and operating system designed to run server hardware.) The client/server setup is analogous to a restaurant with waiters and customers. Some Internet servers take this analogy to extremes and become inattentive, or even refuse to serve you.
Shareware
Shareware is a great concept: try-before-you-buy software. Established in the early ’80s by two small software companies owned by Jim Knopf and Andrew Fluegelman, shareware is a distribution method rather than a type of software. Shareware games, utilities, screen savers, word processors, fonts—you name it—are copyrighted, but they can be passed around more or less freely. However, here’s the rub: if you want to keep using the shareware program after the trial period (usually a month), you’re supposed to register it and pay a modest fee. If you don’t, you’re expected to delete it from your computer. The professional body that oversees this field is the Association of Shareware Professionals.
SLIP
Serial Line Internet Protocol. SLIP is a standard for connecting to the Internet with a modem over a phone line. It has serious trouble with noisy dial-up lines and other error-prone connections, so look to higher-level protocols like PPP for error correction.
SMTP
Simple Mail Transfer Protocol. When you’re exchanging electronic mail on the Internet, SMTP is what keeps the process orderly. It’s a protocol that regulates what goes on between the mail servers.
Spam
“Spiced ham.” Hormel’s famous can o’ additives has given its name to something almost as disgusting: junk email. Spam can be a mass mailing to bulletin boards, newsgroups, or lists of people. But spam is never welcome.
Spider
Also known as a Web spider, this class of robot software explores the World Wide Web by retrieving a document and following all the hyperlinks in it. Web sites tend to be so well linked that a spider can cover vast amounts of the Internet by starting from just a few sites. After following the links, spiders generate catalogs that can be accessed by search engines. Popular search sites like Alta Vista, Excite, and Lycos use this method.
SQL
Structured Query Language. A type of programming language used to construct database queries and perform updates and other maintenance of relational databases, SQL is not a full-fledged language that can create standalone applications—but it is strong enough to create interactive routines in other database programs. If you’re looking into buying relational database software, make sure it has SQL support. Incidentally, SQL was developed as a result of an IBM project called Structured English Query Language, so to this day it is pronounced “sequel,” not “squeal.”
Synchronous communication
Synchronous communication is the technique of choice for ISDN lines because it handles data more efficiently than the typical modem’s asynchronous technique. While asynchronous communication sends smallish blocks of data with lots of control bits for error correction, synchronous techniques use big blocks of data with control bits only at the start and end of the entire transmission. But because of the minimal error checking, synchronous communicating devices must be timed to perfection, and they need a clean line. A modem used over an analog line won’t handle synchronous communication well because a crackle on the line would throw everything out of sync. ISDN routers and internal adapters use synchronous communication. This allows them to transfer data up to 30 percent faster than ISDN modems, which must convert the data they receive synchronously so that it can be transmitted asynchronously through the computer’s serial interface.
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T1
If ISDN isn’t enough digital carrier for you, T1 is getting close. T1 is a term coined by AT&T for a system that transfers digital signals at 1.544 megabits per second (as opposed to ISDN’s mere 64 kilobits per second). Of course, if T1 doesn’t cut it, there’s always T3. (T2 seems to have been bypassed altogether.)
T3
When you’re transferring data across a digital carrier, T3 is the premium way to go. It’s not just three times the capacity of T1, as the name suggests—it’s almost 30 times the capacity. It can handle 44.736 megabits of digital data per second.
TCP/IP
TCP/IP is the very heart of the Internet. It’s a protocol that dictates how computers share information with each other. The great thing about TCP/IP is that it works regardless of computer platform. Macs, PCs, Unix boxes—TCP/IP connects them all. What’s not so great about TCP/IP is that it’s complicated and hard to understand—and your TCP/IP client may not get things right every time.
Telnet
Telnet is an application that lets you log on to a Unix computer. Provided you have an account on that Telnet server, you can then use its resources. A drawback of Telnet is that it’s character-based, so you need to speak Unix to the other computer.
Terminal Adapter
This chunk of hardware converts the data it receives over ISDN to a form your computer can understand. Sometimes mistakenly called an ISDN modem or a digital modem, a terminal adapter handles data digitally and does not need to modulate or demodulate an analog signal. Terminal adapters can be an internal board or an external box that connects to the computer through the serial port.
TIFF
Tagged Information File Format. This graphics file format was designed to be the universal translator of the graphics world back in the 1980s when sharing graphics across computing platforms was a great headache. TIFF can handle color depths ranging from one-bit (black and white) to 24-bit photographic images with equal ease. Like any standards, however, the TIFF developed a few inconsistencies along the way: some graphical software companies estimate that there are more than 50 variations on the TIFF format.
Twisted Pair
Telephone companies commonly run twisted pairs of copper wires to each customer household. The pairs consist of two insulated copper wires twisted into a spiral pattern. Although originally designed for plain old telephone service (POTS), these wires can carry data as well as voice. New services such as ISDN and ADSL also use twisted-pair copper connections.
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Unix
Described by one of its developers as “a weak pun on Multics” (which was an experimental, time-sharing operating system at Bell Labs in the 1960s), Unix took off in the early 1970s as a general-purpose operating system. Since much of the Internet is hosted on Unix machines, the OS took on a new surge of popularity in the early 1990s. Unix comes in many flavors--including Xenix, Ultrix, GNU, and Linux—and runs on a variety of platforms, which makes its development a subject of widespread discussion. But the truly great debate involves how to style the word itself: should it have an initial capital (Unix)? Or should it be in all caps (UNIX)? Since the operating system itself is case-sensitive, the debate rages. Bell Labs’ implementation of Unix is trademarked in all caps; for the other implementations, it’s optional.
URL
Uniform Resource Locator, URLs, are the Internet equivalent of addresses. How do they work? Like other types of addresses, they move from the general to the specific (from zip code to recipient, so to speak).
Take this URL, for example: http://www.usc.edu/People/index.html. First you have the protocol: http:/ then the server address or domain: /www.usc.edu and finally the directory in which the file index.html resides: /People/ The debate rages: is it pronounced “you are ell,” or does it rhyme with “hurl?” Both are widely used.
Usenet
Usenet is a worldwide network of thousands of Unix systems with a decentralized administration. The Usenet systems exist to transmit postings to special-interest newsgroups covering just about any topic you can imagine (and many you wouldn’t even want to imagine).
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V.34
This is the modem standard (pronounced “v-dot 34”) for error correction and compression at speeds of 28.8 kbps.
V.42bis
This is the modem standard (pronounced “v-dot 42 biss”) for error correction and compression at speeds of 28.8 kbps. Bis (French for encore) is an international designation for the first revision of a standard.
Vector Graphics
Computer-aided design (CAD) programs and drawing applications such as Adobe Illustrator and CorelDraw produce graphics that don’t look blocky when you zoom in on them. They scale up easily because they store geometric information about shapes and lines called vectors. These images are unlike pictures from paint programs or scanners, which are called bitmaps.
Viewer
A viewer assists your Web browser by handling files that the browser itself can’t. Viewers can be any type of application, since they may be called upon to handle any kind of file—even sound files. Because it seems weird to use a viewer to play a sound file, some people prefer to call them helpers.
Virtual Memory
What do you do when you run out of real random access memory (RAM)? Easy. Pass it off to virtual memory. To do this you need a virtual memory manager (usually a function of the operating system) that maps chunks of data and code to storage areas that aren’t RAM. Virtual memory is really a part of your hard disk called a swap file, dedicated as a storage area for bits of data in RAM that aren’t being used much. By freeing up RAM, you’re virtually increasing the amount of working memory available to you.
VRAM
Video RAM This type of RAM sits on the better class of graphics display adapters. Unlike its general-purpose cousin dynamic RAM (DRAM), VRAM has dual ports—a design that can read and write data at the same time and is thus faster than DRAM.
VRML
Virtual Reality Modeling Language. The World Wide Web isn’t a linear experience like leafing through and reading a book. The Web enables you to jump around from place to place. But in most cases, you jump from one page-based site to another. HTML is the specification for page-oriented Web navigation. VRML is a 3D navigation specification, hammered out by Silicon Graphics, Intervista Software, and other organizations and individuals. It enables the creation of 3D sites (not necessarily just chat rooms, though this is one example of its use). Many sites and FAQ are devoted to discussing and showing off the technology. The specification is also available online.
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WAIS
Wide Area Information Servers. A software system used to search indexed databases on remote servers, WAIS returns a ranked list of pages or files that you can retrieve from the server. Another plus to WAIS searching is that it enables you to use so-called natural language input; in other words, you can ask simply “Why is the sky blue”? instead of having to master Boolean AND/OR constructs.
Waveform
Waveform is a type of sound that works like a tape recording: speak into a computer’s microphone, and your voice becomes a waveform sound file (typically stored in WAV, AIFF, or AU format). Waveform sounds play back from disk using sound chips in your computer’s system board or on an add-in audio card. System sounds, such as the annoying Windows ding.wav file, and download able audio clips are all waveform sounds.
World Wide Web
Also known as the WWW, the W3, or most often simply as the Web, it originally developed by CERN labs in Geneva, Switzerland. Continuing development of the Web is overseen by the World Wide Web Consortium. The Web can be described (dryly) as a client/server hypertext system for retrieving information across the Internet. On the Web, everything is represented as hypertext (in HTML format) and is linked to other documents by their URLs. The Web encompasses its native http protocol, as well as ftp, Gopher, and Telnet. The best way to learn about it, however, is to try it for yourself.
Wysiwyg
“What you see is what you get”. A catch phrase from the old TV show Rowan and Martin’s Laugh-In that became a desktop publishing byword, Wysiwyg (pronounced “whizzy-wig”) refers to any technology that enables you to see images on-screen exactly as they will appear when printed out. As scalable screen and printer fonts have become more sophisticated, and as graphical user interfaces have improved their display, people have come to expect everything to be Wysiwyg. But it isn’t always the case—and certainly wasn’t in the 1980s, when this term was first applied.
