1GL: First-generation programming language. A 1GL is defined as machine language, the pure, raw bits that make the opcodes that are sent to a computer's CPU. 286: The first AT processor. Now obsolete. 2GL: Second-generation programming language. A 2GL is "assembler" or "assembly" language, which is a language which uses mnemonics for the CPU's opcodes, but is directly translatable into or from machine language. 386: More advanced processor. Also now obsolete. 3GL: Third-generation language. A 3GL is a high-level programming language, such as C. 486: The follow-up to the 386. Even today, a 486 is still pretty good, but really, not many people buy them anymore. That's partly because not many stores sell them anymore. 4GL: Fourth-generation language. 4GLs are similar to 3GLs, but with simpler statements that are closer to normal, everyday human speech. The distinction between the two is open to debate, and some languages are considered to be 3GLs by some people and 4GLs by others. COBOL is probably considered a 4GL by most people. 586: Many people think that a 586 is the same as a Pentium, but actually, it's not. Look under "Pentium" for an explanation of the difference. 5GL: Fifth-generation language. An environment in which you use a graphical user interface to create an application instead of programming the actual code. "Visual" development environments, like Visual Basic, are 5GLs. Abandonware: Software which has been "abandoned" by its publisher. Usually older programs which are too old to be commercially viable, and which have simply stopped being manufactured or sold. This is an important sub-category of software piracy. Although abandonware is still technically illegal to copy because the software companies still own the copyright, it is more freely copied and traded with less fear of legal consequences because the software companies usually do not care enough to pursue legal action (after all, they're the ones who chose to stop selling the program because they didn't think they could make any more money off it). Abandonware is almost exclusively games, although there are exceptions. Abandonare traders often justify their breach of the law by saying they are keeping historical culture alive, by distributing classic software which would otherwise have no way of reaching the masses. This raises an interesting parallel between computer software and other media such as movies and books: Many old movies and books are still available at a video store or bookstore, but old software is very difficult to find at any software store. Some abandonware pirates thus see themselves as the defenders of computing history. ACIA: Asynchronous Communications Interface Adapter. An ancient name for what is today called a UART. ACPI: Advanced Configuration and Power Interface. The successor to APM. Active Matrix: See TFT. ActiveX Control: An OLE control which has been extended for use in an Internet environment. (OLE controls have an OCX extension.) Address Bus: The part of a CPU which controls the memory location the computer is currently reading from or writing to. The size of the address bus limits how much RAM a computer can access. The original 8088 and 8086 chips had 20-bit address buses, allowing them to only access up to 1 MB of RAM. The 286 and low-end 386 chips had 24-bit address buses, allowing up to 16 MB of RAM. The 386DX, all 486s, and the original Pentiums all had 32-bit address buses, allowing up to 4 GB of RAM. The Pentium Pro, Pentium II, and (as of this writing) all Intel CPUs from there on had 36-bit address buses, allowing for up to 64 GB of RAM. Adventure Game: An entertainment program which generally requires walking from place to place, solving puzzles, picking up objects and using those objects, carefully examining just about everything, and talking to just about everybody. Adventure games usually take place in old times, like around the Medieval days, or in the future, but there are some present-day ones as well. Aeron: The definitive office chair of the dot-com world. The Aeron chair became a symbol of the good life in Silicon Valley during the dot-com era of the late 1990s, as well as of the subsequent downfall of the tech industry and the people within it. *Extremely* comfortable, ergonomic, adjustable, and expensive, the Aeron remains a great chair, but its days as a status symbol are largely past. AGP: Advanced Graphics Port. A bus type specifically for video cards. Provides a 66-MHz connection to the system bus (as opposed to the 33- MHz connection of PCI). AGP Aperture: A BIOS setting which controls the amount of system RAM available to your AGP video card. Generally speaking, the more memory the video card can access, the better it performs. However, this takes away from system RAM of course, so it's best not to set the aperture too high unless you have a ton of system RAM. AI: 1. Short for Artificial Intelligence. The art and science of writing computer programs that attempt to be intelligent. Although computers have an easy time making mathematical calculations, they are not so easily made to calculate things that humans find easy, like distinguishing a square from a circle; Complex algorithms are used to make the computer do this kind of thing. Of course, AI is also used for much more complicated things, like figuring out the best move to play in a chess game, or analyzing a molecule's chemical structure. 2. In cyberpunk science fiction, an "AI" is usually a singular object rather than a general concept. An AI is a computer program that uses artificial intelligence, and has been programmed with a life of its own. AIs are given faces, names, and personalities, making them seem like living beings, even though technically they are not. Of course in real life, people usually do not program personalities into their software programs, since doing so is not useful; It's just used as a plot device in books. ALU: Arithmetic Logic Unit. A type of chip used for arithmetic calculations, usually integrated into the CPU on a computer. American Standard Code for Information Interchange: See ASCII. AOL: America On-Line, an information service. APA: All Points Addressable. Said of video modes which support graphics, as opposed to text-only video modes. (It means that all points, i.e. pixels, on the screen can be addressed.) API: Application Program Interface APM: Advanced Power Management Apple: The company which makes the Macintosh. They also used to make other computers (like the famous Apple I and Apple II lines of systems) but not anymore. Application: A program that does stuff. All software is applications, except for operating systems. Arcade Game: The kind of game kids love to play. Usually fast-paced and often involving a lot of gore and guns and ripping out the intestines of anybody who you see or any object that moves (assuming it has intestines). ARPANET: Advanced Research Projects Agency Network. The predecessor to the Internet, the ARPANET was the world's first large- scale global computer network. Begun in 1969 as a research project, it changed the way in which hackers thought about computers. At that time, computers were not in general public use, and so for many years the only people using the Net were people actively involved in computer research or development. But the idea was big enough that it just kept growing, eventually splitting into other networks, particularly MILNET (for use by the military) and NSFNET (National Science Foundation Network). The ARPANET was decommissioned in 1990, having been largely replaced by NSFNET. Artificial Intelligence: Also called AI. Actually a self-explanatory name. Artificial intelligence is what makes computers appear to "think". In a chess game, for example, a computer can be a very good player, often being much better than most human players, and appearing to exhibit real intelligence. But of course, computers cannot truly think, in the same sense that humans can. That's why it's called artificial intelligence. ASCII: Short for American Standard Code for Information Interchange. A widely used code for storing data and stuff. Pronounced askee. ASCIIZ: (of a string) ASCII Zero-terminated. Ending in a null (zero- value) character. For example, normally the string "HELLO" would be stored as a series of five bytes, which in hexadecimal notation would be 48 45 4C 4C 4F. To make this into an ASCIIZ string, you'd add a null byte onto the end, making the string stored as 48 45 4C 4C 4F 00. ASP: 1. Application Service Provider, a company which offers the service of remotely using applications. In other words, you connect to a server and use your application (be it a word processor, spreadsheet, database, or whatever) over a network connection, rather than having to have the application installed locally on your own computer. Although ASPs aren't very useful for individual home users, businesses are getting into them because it gives them access to applications without having the buy those applications, or maintain the computers they're installed on. 2. Active Server Page, a weird type of HTML page which has something to do with Microsoft. Aspect Ratio: The ratio of width to height of a screen or image. For example, an aspect ratio of 2:1 indicates that the width is twice the height. Aspect ratio generally refers to the image area (the frame that holds the image) rather than the image itself. It is an important factor in maintaining correct proportions when a graphic is printed, resized, or incorporated into another document. ASPI: Advanced SCSI Programming Interface AT: Advanced Technology. ATA: AT Attachment interface. Essentially a newer name for what used to be commonly called IDE. ATAPI: AT Attachment Packet Interface. ATAPI is basically the SCSI command set, adapted for IDE. ATM: 1. Automated Teller Machine. 2. Asynchronous Transfer Mode. AUI: Attachment Unit Interface. A type of network cable which uses 15- pin connectors and is used for very short-run connections between components in the same room. Typically they are used to connect a drop cable (bare cable coming from the wall) to a network interface card (NIC). AUTOEXEC.BAT: The batch file which MS-DOS runs on bootup. Runs after CONFIG.SYS (which isn't a batch file and has its own peculiar syntax). AWFL: Acronym With Four Letters. See also TLA. B2B: Business to business. B2C: Business to consumer. Backup: To copy data somewhere else in case the other copy should be lost somehow. Backup File: A file containing a backup. Bad Sector: A sector of a disk (can be either hard disk or floppy disk) which is physically incapable of storing data. This sometimes happens as a manufacturing defect, or it can result from damage to the disk. BASIC: Beginner's All-Purpose Symbolic Instruction Code. A programming language. Bezos, Jeff: Founder of amazon.com. BGI: Borland Graphics Interface. BGP: Border Gateway Protocol. An extension of EGP which offers additional functionality. Big Blue: Nickname for IBM. Bill Gates: See Gates, Bill. Bill Hewlett: Born on May 20, 1913, in Ann Arbor, Michigan. Died on January 12, 2001 at the age of 87. Full name: William Redington Hewlett. Biometrics: Security which uses a person's body, rather than access devices like keycards or passcodes, for authorization. The most common biometric devices are fingerprint scanners. Retina scanners and voice- activated systems which only respond to a particular person's voice are the other two main kinds of biometric security. BIOS: Basic In-Out System. The firmware of your computer. Pronounced "bye-oss". Bit: Binary Element. The smallest piece of data a computer can work with. Can be either 1 (on) or 0 (off). 8 bits make one byte. bitblt: BITmap BLock Transfer. A function of high-performance (relatively speaking) video cards which aids the CPU in moving and displaying bitmaps in Windows. This is a common function of many early or cheap "Windows accelerator" video cards. Black-Hat Hacker: A cracker who hacks to do damage, often deleting files on hacked systems or crashing them. Compare White-Hat Hacker. BLOB: Binary Large Object. A large binary object. BNC Server: A server which is used as a gateway to an IRC server. The purpose of BNCs is to permit the chatter to avoid having their real IP address shown to other IRC users (because the BNC server's address is what appears on IRC, not the actual user's address). BNCs are most popular among lamers for obvious reasons related to avoiding bans and K-lines, but they also have some use in avoiding denial of service attacks. BNCs do not just let you use any hostname you want, however; the domain name must have actually been registered and put on a DNS server. (In other words, they cannot be used to just make up nonexistant domain names.) Thus, they are most often used with shell Internet accounts, on which the shell provider has already created several clever host names for IRCers to use with a BNC server. (BNC is a contraction of "bounce". This is not to be confused with a BNC connector, a type of connector used for coaxial cable on LANs.) Board: See Card. Boot: To start up a computer. Bottleneck: A point in a computer where performance is reduced, slowing the whole system down. For example, in a high-end 3D game, a fast processor and tons of RAM won't help much if your video card is sluggish. And data-intensive applications may be slow if your hard disk (or its I/O interface) is slow. Meanwhile, computers with an ISA bus have an inherent bottleneck because of ISA's slow speed. Box: 1. Computer. 2. Box. Brouter: A piece of networking equipment which combines the functions of a bridge and a router. Buffer Overrun: A condition in which a buffer is being sent more data than it can hold. When a buffer is full and something tries to put more data into it, the data is lost and the buffer is said to have overrun (consider it a synonym for "overflow"). A relatively common example is when the keyboard buffer overflows: The keyboard has a buffer which stores keystrokes which cannot be immediately sent to the computer. If this buffer gets full and you keep on pressing keys, the buffer overruns (most BIOSes indicate this situation by beeping or clicking with each lost keypress). Compare Buffer Underrun. Buffer Underrun: A condition in which all of a buffer's data has been exhausted, when it should still have some data in it. Nowadays, the most common example is when burning a CD-R: The CD-R drive has a buffer where it keeps the data it's burning to the disc. If it runs out of data in the buffer (if the data leaves the buffer faster than it's coming in), the buffer will underrun (because it's empty and expecting more data) and the disc will be ruined. Compare Buffer Overrun. Bug: A flaw in hardware or software that affects how it works in a bad way. Bus: Any physical pathway between the various physical hardware components of a computer. However, "bus" by itself very often refers specifically to the expansion bus. (See Expansion Bus) "Bus" is a shortened form of the full, official term "omnibus connector". Bus Mastering: The technique used by some expansion cards to communicate directly with each other, without the intervention of the CPU or RAM. Normally, devices communicate with each other via the CPU, but bus mastering is basically bypassing the middleman. Most post- ISA expansion buses support bus mastering (PCI, VL-bus, EISA, and MCA all do), but ISA does not. Byte: The amount of storage space needed the store one character. C: A programming language. For some reason, a lot of people don't like programming in C, which is a bit odd to me. C is actually not a bad language. C++: Another programming language, an extension of C. C: Prompt: See DOS Prompt. Cache: See CPU Cache and Disk Cache. CAD: Computer-Aided Design. CADD: CAD And Drafting. CAE: Computer-Aided Engineering. CAI: Computer-Aided Instruction. CAM: Computer-Aided Manufacturing. Capacitor: An electronic component which functions as a tiny container for electricity. You might think of it as an extremely low-capacity battery; It stores small amounts of electrical power for a specific use, but it can't hold enough to actually work as a main power source. Capacitors are most often used in power supplies to stabilize the stream of electricity. If the power to an electrical device is cut, normally the device turns off immediately, but with a capacitor in line with the circuit, the capacitor will keep the device powered for a little longer. This time space is generally just a second or two, but this serves the capacitor's purpose of smoothing out any brief interruptions or variance in the power. Many blackouts last for a fraction of a second. (This is why many radios will keep playing for a couple of seconds even after you unplug them.) Capacitors come in two main varieties: Ceramic capacitors look like small brown flat circles; They are unpolarized, and usually have very little capacitance (typically less than 1 microfarad). Because of their low capacitance, they are usually used for smaller electronic and logic functions. Electrolytic or tantalum ("tantal") capacitors are polarized and have higher capacitance. Electrolytic capacitors are shaped like tiny cans or barrels, while tantal capacitors are shaped like little candy drops. Because of their higher capacitance, they are typically used in electrical applications like stabilizing a power supply. Capacitors tend to block DC and let AC go through. (Inductors do the opposite.) Card: Also called a Board. A little thingy that's sort of flat (but not exactly), and which plugs into your computer. Cards include Video Cards, Diskette/Fixed Disk Controller Cards, and Sound Cards. CardBus: A standard for PCMCIA cards (or "PC cards") which is essentially the same as a normal PC card, except that it supports DMA, and it uses a 32-bit bus, so it runs much faster. CardBus cards will not quite fit into a normal non-CardBus PCMCIA slot; They are the same size, but CardBus cards have an additional tiny protrusion which prevents them from being fully inserted. CAS: Column Address Strobe. Compare RAS. CASE: Computer-Aided Software Engineering. Case: The main box of your computer. The one which contains the motherboard, expansion cards, power supply, internal drives, etc. Also called CPU, even though that term properly refers specifically to the processor chip. Cathode-Ray Tube: The modern-day term for a vacuum tube. Abbreviated CRT. CRTs are still used to display images on most TVs and computer monitors. CD: Compact Disc. Cellular Modem: A modem which connects to a cellular phone to make data calls wirelessly. Although the term "cellular modem" might suggest a modem which has built-in wireless capability, cellular modems don't actually have any wireless capability of their own. Rather, they simply connect (using a special cable) to a cellular phone, then the cell phone must be dialed to reach a data line. Note, also, that each model of cellular modem only supports certain models of cell phone, and so you must make sure your cellular modem and cellular phone will work together before you buy them. CGA: Color Graphics Adaptor. CGC: Clock Generator/Controller. Character: One digit of text, such as a letter, number, punctuation mark, or some other such thing. Spaces are characters, too. Chicago: The code name for Windows 4.0 while it was in development; It eventually was renamed to Windows 95 before it was released. Chipset: A set of chips inside your computer. Specifically, two of them. They control several major system functions, including DMA, bus I/O, IRQ, cache control, and system timing. They don't have any special function of their own, but they are the glue that holds just about everything else in the computer together. CHS: Cylinders/Heads/Sectors. The old way of specifying a hard disk's size in a BIOS. Limited to disk sizes of 504 MB or less, which is why LBA was invented. CIS: CompuServe Information Service. CLI: Command-Line Interface. CLSID: Class ID. A 16-byte value which identifies an individual object in Microsoft Windows. The most commonly-used type of GUID. Cluster: The smallest unit of disk space that DOS can allocate. A cluster may take up one sector on the disk, or it may take up more, depending on the disk type. Floppy disks use clusters which are one or two sectors in size (depending on the size of the floppy), while hard disks use more (sometimes several dozen) sectors per cluster. CMOS: 1. Complementary Metal-Oxide Semiconductor. The place where the BIOS stores its configuration information. Pronounced "see-moss". 2. Complementary Metal-Oxide Semiconductor. The new breed of ICs, which are well-known for their amazingly low power consumption. However, this low power consumption brings with it lower speed; CMOS chips cannot run as fast as most TTL chips. Also, CMOS chips are notoriously sensitive to static electricity damage, while TTL chips are much more robust. See also RTL, DTL, and TTL. CMOS Battery: The battery which stores your CMOS values. These tend to go dead after 3 to 5 years, necessitating a replacement. COBOL: COmmon Business-Oriented Language. A very easy-to-use programming language. Command Interpreter: A program which accepts commands from the user. COMMAND.COM is MS-DOS's command interpreter. Compiler: A program which converts a programming language into machine code. Programs written in languages other than machine language (for example, BASIC, C, Pascal, etc.) must be compiled before they can run. Computer: If you don't know what a computer is, why the HECK are you reading this? A computer is a modern, sophisticated machine which can greatly help you in writing, drawing, playing, calculating, negotiating, or doing just about anything that you can do with a machine. Computers are characterized by their remarkable ability to go obsolete and get replaced by newer, more expensive technology 4 seconds (or less) after they hit the market. Computer Science (CS): The science of computers, comprising several broad fields, including computer programming, information management (which includes gathering, organizing, processing, and presenting data), artificial intelligence (AI) including natural-language processing (NLP), and human-computer interaction (HCI), including virtual reality (VR). CONFIG.SYS: A file in the root directory of a hard disk which contains data telling the computer how it's configured. The other user- configurable startup file besides AUTOEXEC.BAT. Configuration: The way your computer is set up, or "configured". Console: The two parts of the computer the user interacts with the most: The monitor and keyboard. In the very basic classical computer setup, the computer consists of three components: The main case which houses the data-processing circuitry, the monitor, and the keyboard. The case is the "computer" itself, and the other two parts make up the "console". Cooperative Multitasking: The multitasking system used by Windows 3.X and below. Under Cooperative Multitasking, the applications decide when they will run, and for how long. Compare with Preemptive Multitasking. CORBA: Common Object Request Broker Architecture. CPS: Characters Per Second. CPU: Central Processing Unit. The processor. This term is also sometimes used to refer to the case as a whole. (See Case) CPU Cache: Special memory designed to speed up your computer's CPU. This cache memory is divided into two kinds: Level 1 (L1), which is built right into the CPU chip itself, and Level 2 (L2), which is in the form of separate chips on the motherboard. CRC: Cyclic Redundancy Check. An error-checking method. CRM: Customer Relationship Management. A category of e-commerce software. CRT: 1. Cathode-ray tube. 2. A TV or computer monitor which uses a cathode-ray tube to display its image. These are gradually being phased out by the new-generation LCD displays, as well as new technologies like plasma displays, but CRTs are still popular because they're much cheaper. CS: Computer Science. CSU/DSU: Channel Service Unit/Data Service Unit. A hardware device very similar in form and function to a modem, except that while a conventional modem acts as a translator between a computer and a telephone line, a CSU/DSU acts as a translator between a (usually Ethernet) LAN and a WAN technology, such as a T1 line, T3 line, or Frame Relay line. CTC: Counter/Timer Channel. Cursor: The little thing on your screen which indicates where text would appear if you were to type something on the keyboard right now. Cursors can vary in shape. Most of them blink so they're easier to notice. DAM: See RAM. DART: Dual Asynchronous Receiver Transmitter. Data: Information. "Datum" is a word for one piece of information, and data is the plural. You'll find it's a word that comes up quite a bit in the world of computers. Data Bus: The path by which data arrives at (and leaves from) the CPU. Processors are rated according to their data bus size. In fact, whole computers are rated by their processor's data bus size. For example, if a computer is deemed "an 8-bit computer", that means it has a processor which can send or receive 8 bits (to or from the memory or I/O ports) at a time. Dave Packard: Born on September 7, 1912, in Pueblo, Colorado. Died on March 26, 1996 at the age of 83. DBA: Database Administrator DBR: DOS Boot Record. D-Connector: A connector in the shape of a capital letter "D", like the kind used for parallel and serial cables. DDE: Dynamic Data Exchange. DDR SDRAM: Double Data Rate SDRAM. A type of SDRAM which runs twice as fast as regular (SDR, or Single Data Rate) SDRAM. Although many people are making the move to RDRAM, DDR is still popular as a cheaper alternative. DDR SDRAM DIMMs and regular SDRAM DIMMs are physically incompatible. However, they are fairly easy to physically distinguish, as SDRAM has 168 pins, while DDR SDRAM has 184 pins. Also, while plain SDRAM has two notches on the DIMM (one very close to the side so it's easy to quickly tell which way it fits into the slot), DDR SDRAM has only one notch mounted slightly off-center, so it's a little harder to get it properly into place at first glance. In addition, regular SDRAM DIMM slots are usually black, whereas DDR slots are usually some brighter color (typically blue). SDR SDRAM is 3.3 volts, and DDR SDRAM is 2.5 volts. "Dead Zone": A range around the center of a joystick in which all inputs are ignored. This is no negate annoying "drift" caused by tiny variances or pressures on the stick. The dead zone is usually adjustable through software. Although increasing it may eliminate drift, it also increases the minimum possible input, making delicate maneuvers more difficult. DEC: Digital Equipment Corporation, a company with a long and important history in the computer industry, with products that include the PDP family of computers (and the TOPS operating systems that went with them), VAX and VMS, and most recently the Alpha chip. Dedicated: Doing (or intended to do) just one thing. de facto standard: (from Latin "de facto", roughly translated, "in fact") A standard which is not the official standard for an industry, but so widely-adopted that it may as well be. Examples include the 80x86 design for PC CPUs, Microsoft Windows for operating systems, the Sound Blaster specification for sound cards, and PCL for printer page-description languages. Delete: The neophyte's terror. Delete is a verb which means to remove a file from some storage media. Unfortunately, for beginners, it's all too easy to erase a critically important file. Undelete utilities were created for this reason. Desoldering Braid: A strip of paper-like material which is highly absorbent, intended for use when de-soldering electronic components. The braid is pressed between a hot soldering iron and the solder to be removed, and the solder is sucked into the braid, leaving a solder-free component which can then be easily pulled off. DHCP: Dynamic Host Configuration Protocol. Essentially a protocol for assigning IP addresses over a LAN. DHCP is *not* used over WANs (for example, it is not used to assign IP addresses using PPP). Differential Backup: A type of backup which backs up all files with the archive attribute set, but leaves the archive attribute on when the backup is over. Compare Full Backup, Incremental Backup. DIMM: Dual Inline Memory Module. The type of RAM module which superceded SIMMs. Unlike SIMMs, DIMMs can be installed one at a time. They have 168 pins. DIP: Dual In-Line Package. The kind of chip package which has two rows of pins on it, parallel to each other, mounted on opposite sides of a flat rectangle holding the actual microchip. DIPs make it easy to connect to a microchip because it uses those pins, which are big and easy to connect to (they usually plug into a socket). Most chips are DIPs, but CPUs are not: They have lots of tiny little pins arranged in a grid pattern. DIP Switch: A switch mounted on a DIP. These switches are usually very tiny and need something like the tip of a pen to flip (unless your fingers are unusually nimble). Directory: An area on a disk. Instead of just heaping files together in a jumble on a disk, directories are created so that files can be kept in groups. Directories are usually made to keep programs in. Think of a directory as a folder in a file cabinet, and a file as a document in a folder. Disc: A CD (Compact Disc). This is spelled with a C at the end, whereas other types of computers disks are spelled with a K. Disk: A general term which usually refers to either a floppy disk or a hard disk. Not to be confused with disc. Disk Cache: Like CPU Cache, except built into a Hard Disk. Serves the same purpose, however. Disk Drive: A term which encompasses both Hard Disks and Floppy Drives. Divx: 1. (short for DIgital Video eXpress) Formerly, a type of DVD which was coded to "self-destruct" after 48 hours of the first play. The user would then have to pay to view the disc again. Divx players require a connection to a phone line (that's right, they need a special Divx player; They do not play in normal DVD players), so they can dial out and contact the billing office to charge you for additional views of the disc. Although heavily marketed by Circuit City, Divx was a much-hated system right from the start, as consumers did not go for the "pay per play" video model, preferring simply to buy a normal video with the ability to play it as much as they wanted forever. Divx is now almost dead. 2. More recently, a compression format for movies which makes them about 8 to 12 times smaller than a DVD; Approximately 600 to 700 megabytes, or in that range, meaning one would just about fill a standard CD-ROM. Basically, DivX is to movies what MP3 is to music and other audio: The format of choice for sharing them on the Internet. The fact that DivX has the same name as the other Divx confuses people to no end. (Hint: DivX, the compression format, used BiCapitalization on the X, whereas Divx, the rental format, usually doesn't.) DLL: Dynamic Link Library. Used by Windows. DLL files usually have a DLL extension, but they don't have to. A DLL contains functions used in programming. They are libraries of programming functions which you can access so you don't have to create your own function to do something while you're writing a program. DMI: Desktop Management Interface. A specification which is essentially a way of examining a PC's insides and reprogramming it from a remote location. The latest version of DMI is version 2.1. It's usually only used on LANs. DMR: Dennis M. Ritchie, designer of C (the programming language) and considered co-author of Unix (along with Ken Thompson). Ritchie also co-wrote the famous book "The C Programming Language" with Brian Kernighan. (The book is commonly known as "K&R".) DNS: Domain Name System. The system used by the Internet to keep track of human-readable domain names (like foo.com) and their corresponding IP addresses (like 1.2.3.4). See also InterNIC. Documentation: The manuals for something. DOS: Short for Disk Operating System. A software program designed to help you use your computer. DOSes usually include a number of utilities and assorted goodies. The term is also sometimes used to refer specifically to MS-DOS. DOS Prompt: The command prompt for MS-DOS. Also called "C: prompt", because you're usually in drive C: (the first hard disk on the system) when you're there. Download: To copy something into your computer through a modem. Some people spend all day doing this, getting the latest games from the Internet. DPI: Dots Per Inch. DRAM: Dynamic RAM. Your basic RAM. In DRAM, information is stored as a series of charges in a capacitor. Within a millisecond of being charged, the capacitor discharges and needs to be refreshed. This constant updating is the reason for the use of the term "dynamic". Drive: See Disk Drive. DSTN: Dual-Scan Twisted Nematic. The new term for what used to be called "passive matrix". See TFT for more info. DSU: See CSU/DSU. DTL: Diode-Transistor Logic. An IC logic family newer than RTL, but still considered obsolete. Most DTL devices have 900-series numbers. See also RTL, TTL, and CMOS. DTP: DeskTop Publishing. DTV: DeskTop Video. DVD: Digital Video Disc, or Digital Versatile Disc. Just like a CD, but lots bigger. DX: A normal processor with its math coprocessor working. Used to distinguish from SX chips. Dynamic RAM: See DRAM. Dynamic Register: A register on a CPU which behaves like dynamic RAM (DRAM) in that it must be constantly refreshed or it loses its data. The registers are refreshed each time the CPU receives a clock pulse on its clock input pin. Very nearly all computer CPUs in microcomputers use dynamic registers, and therefore cannot be run below a certain clock speed without becoming useless. Probably the only major computer CPU ever made which did NOT use dynamic registers was the Z80; It can actually be stopped by simply stopping its clock input, without losing the data inside its registers. Attempting to do this with any other CPU would result in an instant system crash. EAX: Environmental Audio Extensions ECP: Enhanced Communication Port. A type of parallel port. Some older devices don't support ECP parallel ports, so to use them, you'll need to set the port mode to Normal, assuming your BIOS lets you do this (which it should). EDO: Extended Data Out. A type of RAM which is faster than regular DRAM. Edutainment: Combination of the words "education" and "entertainment". Refers to software (usually games) which, while being fun, also teach math, or reading, or whatever. EGA: Enhanced Graphics Adaptor. EGP: Exterior Gateway Protocol. EIDE: Enhanced IDE. EIDE is like IDE, except it supports LBA, and it's faster. ELF: 1. Extremely Low Frequency. In the range of 5 Hz to 2,000 Hz (2 KHz). 2. Executable and Linking Format. A format of binary file used for executables under Linux. Essentially, ELF files are to Linux what .EXE files are to MS-DOS. Ellison, Larry: CEO of Oracle and friend of Scott McNealy. Full name: Lawrence J. Ellison. EMI: Electromagnetic Interference. "Noise" created by electrical fields which can interfere with data transmission. This is exactly the reason why some data cables are often shielded against interference. Not to be confused with ESD. EMS: Expanded Memory Standard. End User: See also Hacker. The kind of person who doesn't care about how computers work or what's going on behind the screen. End users want to get in, get the job done, and get out, without doing anything with the guts of the computer. In general, end users tend to be technologically uneducated. Engelbart, Douglas: Inventor of the mouse in 1968. He went on to work for Logitech, the world's best maker of mice and mouse-like input devices. EPP: Enhanced Parallel Port. A type of parallel port similar to (but older than) ECP. Error: Something that goes wrong. There's about a million and one errors that can occur inside any computer, no matter how reliable and carefully put-together the components may be. Error Message: An onscreen message informing you that an error has occurred. ESD: Electrostatic Discharge. A jolt of static electricity, one of the most common causes of physical damage to electronic components. Not to be confused with EMI. ESDI: Enhanced Small Device Interface (or Enhanced System Device Interface). ESR: Eric S. Raymond, author and contributor of several books, most notably "The New Hacker's Dictionary". Ethernet: A networking standard, specifying both cabling types and data- link protocol. As such, it occupies Layers 1 and 2 (the Physical layer and the Data-Link layer, respectively) of the OSI model. An almost Ethernet- like protocol is specified in IEEE 802.3. Ethernet is the most popular networking flavor among LANs today, and has been for several years. Unlike most protocols, it uses the CSMA/CD technique for MAC rather than the "token" system, which basically means that on an Ethernet network, any computer can start transmitting over the network at any time, but this raises the possibility of network "collisions". EULA: End-User License Agreement. Expanded Memory: Also known as EMS. Expansion Bus: A bus which connects specifically to the expansion slots. Expansion Card: A card which you plug into your motherboard's expansion slots. Very often shortened just to "Card". (See Card) Expansion Slot: One of the slots on the motherboard. Used for plugging in expansion cards. Usually called just slots. Extended Memory: Also known as XMS. External: An adjective usually used to refer to peripherals. It means outside the case of the computer, rather than inside. Fab: Short for Fabrication Plant. Fabrication Plant: A chip manufacturing factory, which creates chips all the way from the raw silicon wafer stage to the final chip. Fabrication plants cost billions of dollars to build. They are called "fabs" for short. Falling Edge: A transition from a logic 1 to a logic 0. Also called negative edge. FAQ: Frequently-Asked Questions. Despite the name, however, FAQs are not actually frequently-asked questions, but FILES which CONTAIN frequently-asked questions (along with answers to those questions). FAQs often have an extension of FAQ (appropriately enough) even though they're usually plain text files. FAT: See File Allocation Table FCC: Short for Federal Communications Commision. FDC: Floppy Drive Controller. The device which controls a floppy drive. Federal Communications Commision: Also Known As FCC. File: See Directory for a little analogy of what a file is like. File Allocation Table: The place where your computer keeps info on where all your files are stored on a disk. FILE_ID.DIZ: The filename of the "descriptor" file often included with archived files (such as ZIPs). It's basically a simple ASCII text file which describes the contents of the archive. Many BBS software packages search uploaded archives for FILE_ID.DIZ and will automatically use it as the file description. Firmware: Software which actually takes the form of hardware. Firmware is usually a ROM chip which contains code for the software. The only type of firmware in general use is the BIOS, which is the startup program which boots up your computer before control goes to the OS. Floppy Disk: One of those flat things which holds data. Floppy disks are now outdated. Floppy Drive: A machine which can read from and write to floppy disks. Font: A style of text. When you're writing an invitation to have dinner with the Queen, you might use a fancy font, for example. Some people have thousands of fonts on their computer, because different styles of text are important for different purposes. Format: 1. (verb) To basically place a grid on a disk so the computer knows where to put data. The computer can't just throw data anywhere on a disk, it needs a logically-organized grid to neatly fit the data into. Most operating system come with utilities to format disks for you. Disks must be formatted before they can be used on a computer. Disks can also be bought preformatted, so they're ready-to-use right out of the box. 2. FPGA: Field Programmable Gate Array. Frame Relay: A data transmission standard which is based on the older X.25. However, frame relay is a "fast-packet" system designed for digital networks, while X.25 was designed for analog networks. Freeware: Software which is just the same as shareware, except even cheaper: You don't pay anything for it. They don't even ask money after you've tried the program out to see if it looks good. Of course, as you may have guessed, most freeware sucks. But, surprise: There really are some very good freeware programs that exist, made by people who just like to help out without getting anything in return for it. FSB: Front-Side Bus. Full Backup: A type of backup which simply backs up the whole disk. Compare Differential Backup, Incremental Backup. Function Key: The 12 (or sometimes 10) keys which are in a row on the top of your keyboard (or sometimes in two columns on the side), and which are numbered F1, F2, F3, etc. up to F12 (or F10). Function keys are so vaguely-named because they have no set functions. They are the keys usually used for special purposes. See, when you press the letter A key on your keyboard, usually what that does is it types in a letter A. Most of the keys have particular functions that they usually do. But not the function keys: They can do anything, and their functions sometimes vary wildly from program to program. However, some function key generalizations can be made: The F1 key is often used for getting help, and the F2 key is sometimes used in games for turning sound effects on or off. Other than that, though, function key functions will vary. GAL: Generic Array Logic. See also PAL. Gates, Bill: Big, important, president, chairman, CEO, and general head guy of Microsoft Corp. Gates is currently the richest man in the world, because he really knows how to play his cards. Full name: William Henry Gates III. GDI: Graphics Device Interface. Gigabyte: A little more than a billion bytes. GLS: Guy L. Steele Jr., author of "Common LISP: The Language" (the Aluminum Book). Also known as "The Great Quux", the nickname he used when creating the semi-infamous "Crunchly" cartoons. GPF: General Protection Fault. A type of error caused by a program which tries to access a section of RAM which does not belong to it. Running programs are given a particular section of memory with which they can work; When they try to write to memory outside that area, the operating system usually shuts down the program and gives a GPF error. GPU: Graphics Processing Unit. The graphics chip of a video card. GUID: Globally Unique Identifier. A 16-byte data structure for holding IDs of OLE controls. The most commonly-used GUID in today's Win32 programming world is a CLSID (Class ID), but there are also IIDs (Interface IDs), REFIIDs (Reference Interface IDs), and UUIDs (Universally Unique IDs). Hacker: See also End User and Wannabee. Hackers are very technical and knowledgeable people in the world of computers. They're not content to just USE their computers, they have to OPEN UP the computers and SEE what's actually INSIDE the computers. They WALLOW in computers. The term is also sometimes used in a derogatory way to refer to someone who gains unauthorized access to computer systems and/or data banks. Hackers have a tendency to be notoriously insensetive to other people's feelings (because they're more concerned about the feelings of their computers), and most have a very strange sense of humor. They are actually a distinct culture unto themselves and deserve to be recognized as such. Hackers have a set of stereotypes that they tend to conform to. While I think it's going a bit far, they are contained in The New Hacker's Dictionary, Third Edition, which I found to be a fairly comprehensive and entertaining book about hackers. Note that the term "Hacker" can also refer to people who illegally break into computer data... But that's a completely different meaning. Hacking Run: What happens when you have a big project to work on. A hacking run is basically a prolonged period of computer usage, which can last several days (during which time the user does not sleep). Hard Copy: A printed paper copy of something, as opposed to "soft copy", which is an image on a screen. Hard Disk: A disk drive permanently installed in a computer which stays there and is not removed much. Hard Drive: Same as Hard Disk. Hardware: The actual, tangible physical components of your computer. See also Software. HDC: Hard Drive Controller. The device which controls a hard drive. HDL: Hardware Description Language. A computer language, similar to a programming language, that describes an electronic circuit. Very commonly used in specifying chip functionalities when working with FPGAs and the like. The two most common HDLs are Verilog and VHDL. Heat Sink: A thingy attached to modern CPUs to keep them away from other things, to protect from melting or burning. (The Pentium creates very high temperatures when it runs.) Hertz: A unit of frequency. Transtales to "cycles per second". A CPU which runs at 33 MHz runs at 33 million hertz, or 33 million cycles per second. Yes, that is fast, but modern CPUs run much faster than that. Hewlett, Bill: Co-founder of Hewlett-Packard, along with Dave Packard. Full name: William R. Hewlett. HR: Human Resources. A company department. Hub Server: See Leaf Server Huffman Coding: (named after David Huffman, a student who published a paper on this technique in 1952) A compression scheme which assigns a short code to every letter in a file, and uses these shorter codes to effect compression. Distinguished from LZW Coding. Hz: Short for hertz. IBM: Short for International Business Machines. IBM was, for years, the leader in the computer industry, and they invented the original IBM PC. Today, however, IBM has become a has-been. They've been overcome by Microsoft. IC: Integrated Circuit. ICMP: Internet Control Message Protocol. An Internet protocol similar to TCP and IP, except used specifically for control and error information around the Internet regarding the transmission of IP packets. IDE: Integrated Drive Electronics. The most popular hard drive interface. IEEE: Institute of Electrical and Electronics Engineers. An organization that defines standards for network cabling schemes. The IEEE is affiliated with the ISO. IGMP: Internet Group Management Protocol. IGP: Interior Gateway Protocol. There are currently two IGPs in common use: OSPF and RIP. IGRP: Interior Gateway Routing Protocol. IID: Interface ID. A 16-byte value which identifies an interface. A type of GUID. Illegal: (of an instruction or command) Invalid or incapable of being carried out. Illegal instructions are usually ones which the computer will not "allow", either for safety reasons or because of hardware or software limitations. In the computer world, this term does not usually have its real-world meaning, although it has led to confusion when "This program has performed an illegal operation" errors lead users to believe they have broken actual law. Impedance: A property of an electrical/electronic circuit, measuring how much opposition the circuit presents to electricity. Impedance is a combination of resistance and reactance. However, since reactance is a property that only applies to AC (alternating current), you can pretty much equate impedance with resistance if you are using DC. Incremental Backup: A type of backup which backs up all files with the archive attribute set, and turns off the archive attribute afterwards. Compare Differential Backup, Full Backup. Intel: A megagiant company which is the head producer of computer processors. They patented the 8086, 8088, 80286, 80386, 80486, and 80586 (now called the "Pentium") design. Intel has made a few attempts at doing other stuff besides processors, but the truth is, processors is all they do well. And boy, they REALLY do it well! Interactive Fiction (IF): Completely text-based adventure games. Used almost exclusively by die-hard fans of these kinds of games. Intermediate Bus: A bus which connects to the CPU through a buffering controller. This controller is responsible for the speed and timing of data operations, unlike a Local Bus, which allows a device to operate at the same speed as the CPU. Internal: Inside the computer. Internal Speaker: The really bad little speaker that comes with all computers. It was never meant to produce really fancy music or sound effects. Its whole purpose was to make beeps or other basic noises. Computers still have them today, although modern software doesn't use them. Sound cards have taken over. Internet: A computer network which consists of a lot of computers around the world communicating with each other. See IP, PSN, SLIP, and PPP. InterNIC: Internet Network Information Center. A joint venture between the United States government and Network Solutions, Inc. (NSI) which operates the database storing all the domain names on the Internet. Registering domains is done through NSI, and thus they have the sole monopoly on domain name registration. (NOTE: This has since changed. As of October 1998, a new, non-profit, global organization called the Internet Corporation of Assigned Names and Numbers (ICANN) will handle the registration process.) See also DNS. Interrupt Request: A connection to your computer from a device. The IRQs are the data lines through which your computer's components communicate. Intersetion Point: A very fancy name for the cursor. Inverter: Common name for a NOT gate, a logic gate which simply reverses its input. (i.e. it outputs a 1 if it receives a 0, and outputs a 0 if it receives a 1.) I/O: Input/Output. IOPL: I/O Privilege Level. On Intel protected-mode CPUs, a level of control given to a program that affects what it is allowed to do. There are four IOPLs, called simply IOPL 0 through IOPL 3. Code that runs at IOPL 0 can use any CPU instruction and access any I/O address, while code that runs at IOPL 3 is more restricted. IOPLs are often called "ring"s, for example, "ring 1" or "ring 2". IO.SYS: The first file MS-DOS loads when it boots up. IP: Internet Protocol. The main protocol for the Internet which servers on it use to communicate with each other. IP is in layer 3 (the Networking layer) of the OSI model. See also TCP and PSN. IPC: Intelligent Peripheral Controller. IPCP: IP Control Protocol, an NCP used with PPP. See PPP for more information. IP Masquerading: A form of Network Address Translation (NAT) which allows a LAN of several computers to access the Internet using a single "gateway" machine, and "piggybacking" on that machine's IP address. IP masquerading will allow all the computers involved to access the Internet even though they don't have actual IP addresses; All their traffic goes over the IP address of the gateway machine. Besides saving on Internet connections and IP addresses (you only need one to connect a whole LAN of computers), IP masquerading also creates a very secure network, because since none of the machines behind the gateway have "real" IP addresses, it is hard for attackers to get at them. IPsec: A scheme to incorporate Internet security at the network layer (layer 3 of the OSI networking model), which in the Internet's case is IP (Internet Protocol). Previous attempts at implementing Internet security have focused on layer 7, the application layer. Although layer 7 security is effective when properly implemented, the need has been recognized to imbue the Internet with security by changing its fundamental structure, rather than using techniques which simply tack security on top of the protocols. IPsec is, as of this writing, very much still a work in development and has not yet been officially defined or implemented, but it's sure getting a lot of attention. IPX: Internetwork Packet Exchange. A LAN protocol. Specifically, a NetWare protocol for moving information across the network. IPX is in layer 3 (the Networking layer) of the OSI model. Historically, IPX has been important because it was the native protocol of Novell NetWare, and NetWare was the most popular NOS. In the mid-1990s, however, with the uprising of Windows 95 and the Internet, this began to change: NetWare 5 uses IP by default, making IPX effectively obsolete and IP the virtually-universal protocol for both LANs and WANs. See also SPX. IRQ: Interrupt ReQuest IRS: Short for Internal Revenue Service. A widely-despised organization which collects taxes. Why did you look this up? It has nothing to do with computers. IS: Information Systems. A company department. See also MIS. ISA Bus: Industry-Standard Architecture. A type of bus. Now outdated. Should no longer be kept, as it creates the dreaded IRQ limitation which had existed for many decades in PCs. ISO: International Standards Organization. A worldwide organization that defines standards for communications, such as the OSI model. ISP: Internet Service Provider IT: Information Technology. J-Card: 1. A template of paper format used for the back covers of "single slim-line" CD cases, which are like jewel cases except about 75% as thick. See also Tray Card. 2. A sheet of paper printed using this template. JEDEC: Joint Electronic Devices Engineering Council. JScript: A scripting language made by Microsoft and based on JavaScript, but slightly different in some ways. Early versions of JScript were terribly incompatible with JavaScript standards, leading to stacks of errors on most JavaScript-using pages. Microsoft Internet Explorer 3.0, the first browser to use JScript, is particularly vulnerable to these problems. IE 4.0 and subsequent versions have had their JavaScript support cleaned up, resulting in a more-or-less JavaScript-compatible browser. JWZ: Jamie W. Zawinski, a semi-famous hacker for writing the Unix version of Netscape and founding mozilla.org. Runs a personal website at www.jwz.org, which proudly bears a quote from an anonymous Slashdot poster reading: "I have yet to come across so much self- righteous bullshit as when I gaze upon the massive heap of crap that is the jwz web experience." K: Short for Kilobyte. Kerberos: A system of network security in which every connection to a host computer requires a "ticket" of authenticity, which can be gotten from a ticket-granting server (TGS), which is turn requires a ticket from an authentication server (AS) first. Obviously, Kerberos is a complicated system, but it is remarkably effective in promoting network security, which explains its widespread usage. It was first developed on the Athena Project at the Massachusetts Institute of Technology (MIT). (The name originates from Greek mythology, in which Kerberos was a three- headed dog who guarded the gates of Hades.) Kernel: (In Unix/Linux) The part of the OS which contains the main startup code. Basically the heart of the entire OS, and one of the three main parts of it (the other two being the shell and the file system). Keyboard: The board with keys on it. Kilobyte: 1,024 bytes. KVM: Keyboard-Video-Mouse. Used in reference to KVM switches. L2TP: Layer 2 Tunneling Protocol. Essentially an extension of PPTP. LAN: Local Area Network. A relatively small computer network which is usually owned by a single organization (such as a business) and usually confined to one building. Used for things like company employees exchanging messages and files with each other. Compare with WAN. Laptop: A cute little computer that fits in your hand and which you can carry around with you. In this age of computer-mania, the idea of laptops has become enourmously popular. Just about every businessman has one. The term "laptop" often encompasses the entire range of portable computers, including Notebooks (which, officially, are actually smaller than real laptops), and sometimes Subnotebooks (which, as you may have guessed, are smaller still). Laptop Computer: See Laptop Large Mode: Often used in the BIOS as a synonym for LBA mode (referring to the way the BIOS accesses the hard disk). Latch: An electronic logic device which can store a logic bit (1 or 0) until it is needed. A latch usually has three connections: An input, an "activate" line, and an output. Normally the latch contains whatever is on the input line. When the "activate" line goes high, the latch outputs whatever value it is storing. When the activate line goes low again, the latch goes back to storing the input state. LBA: Logical Block Addressing. The new standard in translating a hard drive's specifications for the BIOS. Used instead of old-fashioned CHS mode because it supports drives larger than 504 MB. LBA is sometimes informally called "Large Mode". LCP: See PPP Leaf Server: In IRC networks, a type of server which other IRC servers cannot connect to. Leaf servers are used for lower-bandwidth servers which probably couldn't handle the added load of other servers connecting to them. This is opposed to a hub server, an IRC server which other IRC servers can link to. (The name is by analogy with a tree branch: Leaves cannot connect to other leaves, only the branch. Hence, a leaf is a stand-alone outcropping which cannot have anything else growing from it.) Legacy: Old. A polite euphemism. The term "legacy systems" is often used to describe systems which are obsolete, but still in use because they still work, and newer equipment would be too expensive. LFN: Long Filename. A filename which takes advantage of Windows 9x's ability to store filenames longer than the DOS limit of 8 characters plus a 3-character extension. Light Pen: The pen-like stylus that you use to write directly on the screen. You need a special monitor to use these pens. Most computers don't have them. Linmodem: A modem which was designed to only work with Windows and normally requires Windows device drivers, but which can be used under Linux through Linux device drivers which emulate the Windows ones. This term derives from Winmodem. You can find out more about Linmodems and the Linux drivers that have been created for them at www.linmodems.org Local: On this computer (the one you're sitting at right now). Opposite of remote. Local Area Network: A network of computers which is almost always confined to a single building, and if not, certainly not very far beyond that building (less than 1 kilometre). Used in businesses where all the computers in the building are linked together through wires in the walls. Local Bus: An expansion bus which is directly wired between the connector and the CPU. A local bus connects a device directly to the CPU. Compare Intermediate Bus. Logic Bomb: A computer program (usually a virus) which is set to trigger when certain conditions have been met. This is similar to a time bomb, except a time bomb's trigger is a particular time, whereas logic bombs are triggered by "logic", such as a particular program being run or other non-time-related conditions. See also Time Bomb. Lord British: Pen name of Richard Garriott, designer of the legendary Ultima series of computer role-playing games and a computer gaming legend; Given the nickname by college buddies because of his polite manners. LPB: Low-Ping Bastard. Used in online action games to describe someone who is thought to be doing well simply because of lower ping latency (usually caused by a fast Internet connection). LPT: A parallel port. DOS supports up to 3 parallel ports and labels them from LPT1 to LPT3. This stands for "line printer". LUN: Logical Unit Number. A number assigned to a non-physical device which is part of a SCSI device. Devices with LUNs are not attached directly to the SCSI bus, as devices with PUNs are (see PUN). Instead, they are connected to the SCSI device, and that device, in turn, is connected to the bus. A maximum of eight LUNs can be attached to any device with a PUN. In most cases, however, a single LUN is simply used as the logical device for the physical device (much as a physical hard disk often has just one "logical" hard disk). LVD: Low-Voltage Differential. Usually used in reference to Ultra2 LVD SCSI drives, which have two advantages over drives using other interfaces: They have higher burst transfer rates (80 MB/second), and longer maximum cable lengths (almost 30 feet). LZW Coding: (named after Lempel, Ziv, and Welch) A compression scheme which attempts to find commonly-recurring groups of letters in a file, and then uses a single token to represent these groups. Distinguished from Huffman Coding. Mac: Short for Macintosh MAC Address: An address used to identify a physical network device on a network. MAC addresses are sometimes called BIAs (Burned-In Addresses), because they are set inside a NIC (Network Interface Card) at the factory by being burned into ROM. A MAC address is permanently set in a network device's ROM chips and cannot be changed other than by altering those chips. So how do people avoid getting conflicting MAC addresses on the same network? The answer is simple but amazing: Every NIC in the world has a different MAC address burned into it. Although it seems hard to believe that every NIC ever made could have a different address built into it, it becomes easier when you understand the mechanics of a MAC address. A MAC address is 48 bits (6 bytes) long, and those 48 bits are divided in half: The first 24 bits are an identifier for a particular NIC's manufacturer. Every manufacturer is assigned an ID by the IEEE (that's right, NIC manufacturing is partially regulated by the IEEE), and they must use their own 24-bit ID in those first 24 bits. (This 24-bit identifier which each manufacturer has is called an Organizationally Unique Identifier, or OUI.) Then, the last 24 bits form each individual card's address. As long as the manufacturer keeps track of what addresses it has already manufactured and makes each one unique, global uniqueness of each card's BIA is assured. Macintosh: Apple's signature computer. Also the most successful. Main Menu: The central menu of a program, usually displayed when it first starts and which you can go back to from more specific menus. MAPI: Messaging Application Programming Interface. Markham: A city in Canada, directly north of Toronto's east end, and famous (at least locally) as "the Silicon Valley of the North". Several major high-tech companies, including IBM, Compaq, Apple, Novell, Sun Microsystems, Motorola, ATI, Canon, Autodesk, Lucent Technologies, Toshiba, Mitsubishi, Philips, Hyundai, and Borland have their Canadian headquarters in Markham. It probably has the highest concentration of such companies of any city in Canada, although the high-tech industry is also unusually prominent in Richmond Hill, just west of Markham. Max Headroom: A TV show of the 1980s which was the first (and, nearly 20 years later, still the only) cyberpunk TV program. Being well ahead of its time and too intelligent for the typical TV viewer, it was canceled after a single season, producing only 14 episodes, which originally aired in 1987. (Prior to that, Max Headroom actually began as a made-for-TV movie in the UK.) MBR: Master Boot Record. MCAD: Mechanical CAD. McNealy, Scott: CEO of Sun Microsystems and friend of Larry Ellison. MDA: Monochrome Display Adaptor. MDI: Medium Dependant Interface. A port or socket on an Ethernet network attachment unit which uses a regular wiring diagram. Compare MDIX. MDIX (also spelled MDI-X): MDI crossover. A port on an Ethernet attachment unit which has its wiring internally crossed, negating the need to use a crossover Ethernet cable. Note that many modern Ethernet devices support auto-MDI/MDIX switching, meaning that they will automatically detect whether crossing over is necessary or not; Such devices can use either straight-through or crossover twisted-pair cables to connect devices, regardless of whether they are computers or other network devices (like hubs, switches, routers, etc.) Megabyte: 1,024 Kilobytes, or 1,048,576 bytes. Megahertz: 1 million hertz. Memory-Mapped I/O: A system in which the CPU performs I/O (input/output) via the memory buses (the address bus and the data bus). It is necessary to do I/O this way if the CPU has no separate I/O bus. A small portion of memory space is reserved for I/O space, and the CPU reads from/writes to peripheral ports in the same way as it reads or writes the memory. Thus, the memory space is usually divided into three main areas: RAM, ROM, and I/O. "Memory" addresses used for I/O cannot be used for RAM/ROM access, and so steps must be taken to ensure that the CPU does not try to store information in these addresses, leading to "holes" in the actual RAM space. Typically, the memory controller chip will disable the RAM/ROM chips while I/O addresses are being accessed so they will not interfere. The classic Z80 CPU as well as Intel's famous 80x86 CPU lineup have separate "memory access" and "I/O access" output pins, allowing the hardware designer to activate or de-activate devices depending on whether the CPU is performing a memory access or an I/O access; Under such a system, creating "holes" in the actual memory is not necessary. Although this is not technically a dedicated I/O bus, since the information is still traveling over the same buses used to access memory, this feature means that the x80 CPUs are usually considered to have separate memory and I/O spaces. The 6502 does not have this feature, and thus must use true memory-mapped I/O. Memory-Mapped Video: A method of displaying stuff on a monitor in which each pixel corresponds to a particular location in the computer's memory. The PC and most other modern computers use memory-mapped video. Some pre-PC computers used "terminal" systems in which letters were produced, but the computer had no "memory" of what was being shown on the screen. Menu: A list of choices, much like the analogous menu of a restaurant. Mess-DOS: Old slang name for MS-DOS, so named back then because it was a clunky OS with stupid limitations (and, in a few ways, still is). Metastable: In a state between two stable points. In the context of digital electronics, this refers to a part of a circuit which is neither "high" (1) nor "low" (0), but some state in between. For example, many electronics run on 5 volts; In these electronics, 5 volts is a binary 1 and 0 volts is a binary 0. If any part of the circuit is at 2.5 volts, it is in a metastable state, and any electronics affected by it will be confused. Is it 1 or is it 0? In computers, metastable states are usually a problem when a circuit receives input when it's not supposed to, as a result of bad timing. If a circuit is supposed to be at 0 volts and something else sends it 5 volts, for instance, it will probably end up being at some voltage in between, which will probably make the whole computer crash. This is supposed to be avoided with proper timing implementation, ensuring that the system timers "wait" before doing anything to make sure that they will not be hit by a metastable condition. This kind of synchronization problem is one of the most confounding and frustrating problems in digital computer hardware design because of its unpredictability and difficulty in diagnosing or analyzing. MFT: Master File Table. MHz: See Megahertz Micron: A unit of measurement, one thousandth of a millimetre. Yes, that's very small. Microsoft: The current leader in computer productivity stuff. As it is owned by Bill Gates, Microsoft is a multibillion-dollar business. They're the ones who stole IBM's thunder. Microsoft DOS: See MS-DOS. Microsoft Windows: The most commonly-used OS on home computers today. This is either a good thing or a bad thing, depending on who you are and what you use computers for. Millisecond: 1/1000 of a second. Used to measure seek times of disk drives. MIS: Management Information Systems. A company department. See also IS. MMU: Memory Management Unit. Mobo: Slang for motherboard. Modem: Short for "modulator-demodulator". A modem converts ("modulates") computer data into signals that can be sent over telephone wires, and it also re-converts ("demodulates") signals from the phone line back into computer-speak. The modem itself has a cable running out of it that you plug into a phone jack, and another cable that you plug into your computer (or, some modems plug directly into the inside of your computer without any cables). So the modem actually acts as a translator between your computer and the phone system. Momentary Switch: A switch which is meant to be only triggered for a moment before going back to its "normal" state. A button which does not stay in when you push it is a momentary switch. Compare Toggle Switch. Monitor: The television-like device on your computer which shows stuff. Monochrome: One-color. A monitor can be monochrome, or a Video Card can be. Moore's Law: In 1975, Gordon E. Moore (who was, at the time, chairman of Intel) predicted that the density of transistors on microprocessor chips would double approximately every 18 months. Although at the time, he intended this only as a general rule of thumb, the next several years showed chip development that stayed incredibly true to this forecast. Indeed, whenever transistor density is charted on a time graph, it is seen that Moore's prediction was so uncannily accurate that it has since been informally known as "Moore's Law". This "law" has since become legendary in the computer and microprocessor industries. Moore, for his part, admitted he had no idea his statement would be so well-remembered decades later. (Historical note: Moore's 1975 statement was actually a revision of an earlier prediction he had made in 1965, in which he had forecast only 12 months for each successive doubling of transistor density.) Motherboard: The biggest board inside your computer. Move: I was going to define this, but it has basically the same meaning in computers as in other areas of life, so I'll just leave it at that and no further definition is necessary. MPC: 1. Multimedia PC. 2. Can also refer to the MPC Multimedia PC standard, which was a very funny joke that came out several years ago. The idea was to create a standard which computers should adhere to, so they could ensure good multimedia performance. The standard was laughable, because its specifications were woefully low, and also because nobody seemed to know what it was: Ask 10 different people what the MPC standard was, and you'd get 10 different answers. Some said it specified something, others said it needed something else. There were also MPC-2 and MPC-3 standards which came out later, and which were intended to be updated versions of the MPC standard but which suffered from the same problems. For a while, computers even started getting a cute MPC logo on them (which was more "multimedia" than the standard itself) which was intended to indicate that the computer adhered to the standard. If you see such a logo, the computer you're looking at is not something you would want to have. MPEG: Motion Picture Experts Group MRU: Maximum Receive Unit. See also MTU. MS-DOS: Microsoft DOS, the classical operating system for computers. DOS is text-based, so it's not nearly as graphical and cutesy-easy-to-use as Windows, but it's also generally faster than Windows, and it gives you more direct control over the computer, which is why some advanced computer users prefer it. MS-DOS Compatibility Mode: A disk-access mode in which Windows uses 16-bit disk access rather than 32-bit. This will cause your disk drives to be slower, but should otherwise function identically to normal 32-bit mode. This is usually caused by a driver problem (e.g. a drive using 16-bit drivers). MTU: Maximum Transmission Unit. The largest unit of data a communications terminal (usually a modem) is allowed to transmit. Usually expressed in bytes. See also MRU. Multisync: (of a computer monitor) Able to automatically detect and synchronize with any video mode it receives from the video card. This is important because older monitors had limited ranges they could support; Some couldn't go up to 70 Hz vertical refresh rate, for example, and many didn't support high resolutions. In fact, some monitors would get permanently damaged if you tried to set them to a refresh rate higher than they could support. Modern monitors, however, are all multisync, and will automatically adjust to just about any refresh rate and resolution you can throw at them. Multitask: To do more than one thing at once. Multitasking is not used to refer to PEOPLE doing two or more things at once (except humorously), it refers to COMPUTERS doing several things at once. Nanosecond: One billionth of a second. Used to measure speeds of chips. NBM: Nothing But Microsoft. NCP: See PPP NDS: Novell Directory Services. NDPS: Novell Distributed Print Services. NEPS: Novell Enterprise Print Services. NetBEUI: NetBIOS Extended User Interface. A newer version of NetBIOS. Pronounced "net-BOO-ee". NetBIOS: Network BIOS. A BIOS (developed by IBM) which allows a computer to boot from an operating system on a network. In other words, the computer doesn't need the OS installed locally on itself to work. NIC: 1. Network Interface Card. The attachment that connects a device (usually a computer) to a network. NICs usually take the form of a PC expansion card. 2. The Network Information Center, which maintained and distributed the complete host name and address database of the Arpanet (back when the Arpanet still existed). The NIC was located at SRI International in Menlo Park, California (a part of Silicon Valley, near San Francisco). Its network address was SRI-NIC.ARPA. (The .ARPA top-level domain no longer exists, of course, as it belonged to the Arpanet). The reliability and bandwidth problems associated with housing the entire network's host table on one computer eventually led to the DNS system which is in use today. Norton, Peter: The man who first invented undelete programs, thus gaining a reputation as a computer utility genius. He has a collection of utilities named after him: The Norton Utilities. NOS: Network Operating System. Notebook: See Laptop Notebook Computer: See Laptop Novell Netware: The most commonly used NOS for adding LAN support to a computer already running MS-DOS. NPC: Non-Player Character. Used in computer games to refer to characters other than yourself. (Also sometimes said to stand for Natural Player Character (In Role-Playing Or Adventure Games) or Normal Player Character (In Simulation Games).) NVRAM: Non-Volatile RAM (i.e. RAM which doesn't go empty when the computer is turned off). Object Code: Code within an Object File. Object File: A file which is half-way on the journey from source code to executable file. When source code is compiled, it is usually not immediately made into an EXE file; Instead, it is placed into what's called an object file. The object file contains the machine-language code for the program routines in it. Object files are later linked into executable files with a program called a linker. The reason this is done is because the executable file must contain the code for all the functions it will need. As an example, suppose you write a program in C and you use the printf function. You do not define the routine for printf since it already comes with C. The printf code is stored in an object file that already comes with your C compiler. Later, after you've compiled your program, it will be in another object file, and the object files your program needs (like the one with printf in it) are linked with the object file that is your program, and the linker makes a ready-to-run EXE out of them. Object files are usually signified with a .O extension, so your compiled program might be (for example) MYPROG.O before it's linked into MYPROG.EXE. The code inside object files is called Object Code. OCR: Optical Character Recognition. OCX: A file extension which indicates a custom OLE control. ODBC: Open Data Base COnnectivity. A programming API which allows applications to access the data in a database created by a database application. ODBC is SQL-centric, meaning that the database application which created the database usually needs to use SQL for ODBC to work with it; However, this is not a problem, since most database programs do use SQL, as it is the standard database query language. ODBC could be used to allow a programmer to write a program in (for example) C, and have this program access the data in a database made by (for example) Microsoft Access via SQL. ODBC can be used with any programming development tool that supports it, although in today's Internet age, ODBC is probably most often used with e-commerce sites to allow Perl scripts on a website to access the company's database. OEM: Original Equipment Manufacturer. OOPS: Object-Oriented Programming System. OLE: Object Linking and Embedding. Sometimes spelled out, O-L-E, but usually pronounced like the Spanish word for bull (which is spelled exactly the same way). OnBoard: This means "built into the motherboard". In the old days, computers had a very important card inside them which controlled the floppy drives, hard drives, and ports. Nowadays, however, it's customary to build these functions into the motherboard instead of on a separate expansion card, so they're said to be "OnBoard". On The Fly: (adverb) Performed without a need for interruption in service. For example, if you could change a computer's configuration without rebooting it, that would be changing the configuration on the fly. Onscreen: An adjective, meaning that something is being shown on the monitor of a computer. Op Amp: Operational Amplifier. Operating System: The piece of software which basically runs your programs. DOS is an operating system, and so is Windows. Operating systems don't do anything by themselves, they still need applications to perform useful tasks. Optical Character Recognition: See OCR. OS: Operating System. OS/2: IBM's failed attempt to make an OS more popular than MS-DOS or Windows. Oscillator: An eletrical circuit that "oscillates" its output, meaning the output switches on and off at a rapid frequency. Oscillators are needed by analog speakers (which produce a tone that varies by the frequency of the oscillation). OSI Model: Open Systems Interconnection Model. A seven-layer model developed by the ISO that describes how a terminal and computer communicate on a LAN. The actual layers are (in order, from layer 1 to layer 7): Physical, Data-Link, Network, Transport, Session, Presentation, and Application. Adherence to this model provides a foundation for different vendors' products to interoperate. The Physical layer defines the hardware; The raw bit-level handling of the data. Common protocols which exist in the Physical layer include IEEE 802 and ISDN. The Data- Link layer is the layer which creates data frames, often referred to as "packets". It creates the packets from the raw bits. A common protocol that exists in the Data-Link layer is the LCP (Link Control Protocol) used with PPP. The Network layer is responsible for addressing and routing the packets. Common protocols which exist in the Network layer include IP, IPX, ICMP, and IGMP. The Transport layer handles transmission issues, like flow control and error-detection and -correction. Common protocols which exist in the Transport layer include TCP and SPX. The Session layer is responsible for synchronization of the various nodes on the network. The Presentation layer handles translation from one protocol or language to another. It translates from the network transmission format to the application's format, and vice-versa. Lastly, the Application layer handles the actual user interface. Common protocols which exist in the Application layer include Telnet, FTP, SMTP, and DNS. OSPF: Open Shortest Path First. A routing protocol. Specifically, an IGP. Packard, Dave: Co-founder of Hewlett-Packard, along with Bill Hewlett. Packet: See under PSN. Page: 1. A graphics screen stored in the computer's memory. In a memory-mapped video system (like the IBM PC and compatibles), there are certain sections of memory which contain the image that actually gets sent to the computer's monitor; The image is manipulated by simply changing those memory values. However, although only one set of memory values can be displayed on the screen at a time, many computer architectures have more than one separate video page in memory, so that different images can quickly be changed on the screen by simply changing the active video page. This way, the entire screen does not have to be re-created in memory; You can change what's on the screen simply by switching from one active page to another. This can be used to create various effects via "page-flipping". This is mostly obsolete information, however; Page-flipping was an important video trick in the early days of home microcomputers, but it is rarely used today. 2. A unit of EMS memory. PAL: Programmed Array Logic. See also GAL. Palmtop: A palmtop computer. Palmtop Computer: One which fits in the palm of your hand. PAN: Personal Area Network. A network with functionality restricted to a single individual. PANs are used for connecting individual devices used by a single person; For example, networking your notebook computer to your desktop computer. PANs also often involve linking of PDAs and cellularphones. Parallel Cable: One which connects to a parallel port. Parallel Port: A type of port on the back of the computer, usually used for printers. Passive Matrix: See TFT. Patch Panel: A panel with rows of modular telephone-style jacks, roughly analogous to the "breadboards" used in electronics work, which allows one to connect and disconnect wires at will. See also punch-down block. PC: Personal Computer PCB: Printed Circuit Board. PCI Bus: Peripheral Component Interconnect. A type of bus. Current standard. PCMCIA: Personal Computer Memory Card International Association. A standard for small (roughly credit card-sized) cards which can connect to a special slot on a computer and act as peripherals. PCMCIA cards are usually used only in laptop/notebook computers because of their compactness, and they generally serve purposes like being modems or removable hard drives. One thing that really appeals about them is that they're truly plug-and-play, and were that way long before USB existed; It's a bit of an oddity that USB became an industry standard years later, but PCMCIA was pretty much relegated to portables. There are three types of PCMCIA card standards: PCMCIA Type I was often used for flash RAM; Its cards had a thickness of 3.3 mm. (Past tense is used for PCMCIA Type I because it is no longer in general use.) PCMCIA Type II cards are usually used for PCMCIA modems and NICs; Their cards are 5 mm thick. PCMCIA Type III cards are usually hard drives; They are 10.5 mm thick. There are currently no plans to create a PCMCIA Type IV standard. Because of the somewhat long-winded acronym, the term "PC Card" has become preferred over "PCMCIA" in recent times; This, however, has led to some confusion, since PCMCIA cards are certainly not the only cards you might find in a PC. Peltier Cooler: A cooling device placed over a computer's CPU to cool it down. Peltier coolers provide heavy-duty cooling power, and are usually considered extreme for end users. They are used almost exclusively by people doing things like heavy 3D gaming, overclocking, or filling their systems with a lot of devices which generate heat. Peltier coolers work using the Peltier effect, named after the Frenchman Jean Peltier who discovered it. It makes it possible to create a solid-state electrical device which can efficiently transfer heat from one place to another; Peltier coolers have a cold end (the one you put next to the CPU), and a hot end (the other end, which collects all the heat transferred from the CPU). Although they are very powerful, they have been plagued in the past with some serious problems. First and foremost, they tend to create condensation droplets on the CPU, and any water getting on electronic circuitry is a serious thing. Secondly, when the computer is turned off, generally the Peltier cooler's heat (at the hot end) dissipates throughout it, and it ends up getting pretty hot for a while until it can cool down, meaning that for several minutes, a hot object is pressed right next to the CPU. This usually isn't a huge problem, since by that time the CPU isn't generating any more heat of its own, but even so, it's not something to be ignored. Then there's the massive power requirements. A Peltier cooler may be solid-state, but that doesn't mean it doesn't need much power. On the contrary, some of them need huge amounts of power, often more than the average power supply can spare. (In the ballpark of 70 watts or more.) And finally, Peltier coolers are huge, and finding room to mount them on a CPU inside today's already- cramped computer cases is no small trick sometimes. Pen: In computers, refers to the light pen. Pentium: A processor from Intel. Currently the most popular type of processor for PCs. Some people know that a Pentium is NOT the same as a 586. During the era of the 286, 386, and 486, Intel just kept bumping up the numbers by 100, always keeping the "86" ending. (Actually, interestingly, the proper terms for these processors are the 80286, 80386, and 80486, which is why they're sometimes called the 80x86 family of processors, but most people drop the 80 at the beginning.) Anyway, after the 486, Intel decided to use a name instead of a number. You see, numbers cannot be trademarked. Names can. So Intel used the name Pentium instead of 586. So if you see a computer which has a 586, that means it's not an Intel chip. It's most likely either from AMD or Cyrix. But if you see a computer which declares it has a Pentium, you can be assured, it's a genuine Intel piece of work. Peter Norton: See Norton, Peter. PHP: A Web scripting language which is server-side, meaning it runs on the Web server rather than the browser's computer (unlike client-side languages like JavaScript or VBScript, which do run on the client's computer). In this respect, PHP is similar to Microsoft's ASP (Active Server Page) and JSP (JavaServer Pages), with one important exception: It's open-source. The PHP homepage can be found at www.php.net or www.php.org PIA: Peripheral Interface Adapter. A chip in ancient computers which had the job of interfacing with the keyboard, ports, etc. Interface chips for peripherals still exist in today's computers, but are usually built separately instead of as one central peripheral controller. Ping: 1. A function which checks to see if there is a route to a particular computer. Ping tries to connect to another computer, and then reports whether the connection was successful or not. It's usually used as a diagnostic tool to see if a connection between two systems is possible. On the Internet, ping is done with the ICMP Echo function. (The word "ping" itself is not used in RFC 792, the RFC which defines ICMP.) Ping is sometimes said to stand for "Packet INternet Groper". 2. A program which performs this function. PIO: 1. Programmed I/O. A method for accessing hard disks in which the disk is access through the system's I/O ports, meaning the CPU is used as a messenger. PIO is much slower than DMA mode, in which the hard disk reads and writes directly to/from memory, without intervention from the CPU. Maximum data transfer speeds for each of the PIO modes are as follows: PIO0 = 3.3 MB/s; PIO1 = 5.2 MB/s; PIO2 = 8.3 MB/s; PIO3 = 11.1 MB/s; PIO4 = 16.6 MB/s; PIO5 = 22.2 MB/s. 2. Parallel I/O. (As opposed to serial I/O.) Piracy: The practice of illegally copying programs and giving them to other people. While some programs can be legally copied and given to others (See shareware and freeware), programs that you buy from the shelves of your local software store are copyrighted by the company that makes them, and if you make copies of the disks in there, you're breaking the law. Well, actually, it's OK to make copies for yourself, just in case you want to create a backup of that program or whatever, but if you give copies to somebody else, it's piracy, and it's illegal. See also Warez, Abandonware. Pirate: Someone who engages in piracy. Some pirates form groups and they create huge BBSes which contain freely downloadable copies of many commercial programs (most often games). These BBSes are very secretive affairs, since they would be shut down by the police pretty quick if anybody found out about them. Pirates often want to help out others by giving them free software, and some are pretty good at computer programming, so they reprogram software to remove all "copy protection" from it, then give it to others or upload it to their BBS. Pixel: Picture element. One of the tiny dots on your computer's screen which make up the whole image. Platform: A frame of computer system. Platforms generally are not compatible with one another. Examples of platforms include the IBM PC, Macintosh, Atari, Amiga, and Commodore. In addition, in PCs, MS-DOS and Windows are sometimes (note I said sometimes) considered to be two different platforms. There is some confusion in the industry over whether this term refers to hardware only, or if it includes operating systems. Classically, the term only refers to hardware, meaning that (for example) DOS, Windows, Linux, and OS/2 are all part of the same platform because they all run on IBM PC-compatibles. However, the term is sometimes used to refer to operating systems as well, in which sense DOS, Windows, Linux, and OS/2 *ARE* platforms. Platter: A flat, circular plate inside hard disks. Platters are coated with magnetic particles and they are the parts that actually hold the data inside the disk. They are usually made of aluminum. PLCC: Plastic Leaded Chip Carrier. Point: A unit of measurement for measuring text. One point is 1/72 of an inch. Polling: A method of data transfer in which the receiving device repeatedly checks if data is available from the sending device, or, inversely, in which the sending device repeatedly checks if the receiving device is ready to receive data. For example, a CPU might receive its data from a modem by constantly asking the modem if it has any data. Polled I/O is the way peripherals used to communicate with the CPU in the early days of computers, but it is rather inefficient because it ties up a lot of CPU cycles just polling devices. The alternative is interrupt- driven I/O, which is much more popular than polled I/O today. Interrupt- driven I/O uses interrupts, which are announcements that a particular waiting period is over. For example, a modem might use an interrupt to let the CPU know that it has data which it wants to send to the CPU. Interrupts are so named because they cause the CPU to interrupt whatever it is doing to attend to the peripheral; The CPU actually stops executing instructions from memory and performs a specific routine that attends to the needs of the peripheral, then goes back to executing instructions normally when the interrupt routine is over. Portable Computer: Just what the name says. POST: Power-On Self Test. The test performed by the BIOS every time you turn on the computer or reboot. Power Macintosh: The final laughable attempt by Apple to kill the PC. The ridiculously-named "Power" Macs could run software written for both the Macintosh and the PC platforms, but they ran PC software at a speed about equivalent to a 25 MHz CPU. They were a complete joke, and the killing blow to Apple, which had already been faltering badly at the time. Power Supply: The unit which converts the AC power from your electrical socket in the wall to DC power which the computer uses. PPP: Point-To-Point Protocol. Currently the most popular protocl for establishing dial-up connections the the Internet. PPP is similar to (but more robust than) SLIP, which lacks support for data compression, error detection, and multiple protocols on a single line. PPP is not a complete protocol unto itself. It is a layered protocol, beginning with LCP (Link Control Protocol), to establish the link. After the link has been initialized, a variety of NCPs (Network Control Protocols) can be employed to use a particular protocol over the link. For example, IPCP (IP Control Protocol) is used to transport IP over PPP. As you might guess, LCP is in layer 2 of the OSI model (the Data-Link layer), and the NCPs are in layer 3 (the Network layer). PPTP: Point-To-Point Tunneling Protocol. A somewhat enhanced form of PPP that uses "tunneling" (encapsulating packets of data written for one network protocol inside packets used by another) to basically allow TCP/IP data to be sent over non-TCP/IP networks. The most common use of this is to join physical networks together to form "virtual Internets" using the actual Internet as a go-between. PR: Public Relations. A company department. Preemptive Multitasking: The multitasking system used by Windows 95 and up. Under Preemptive Multitasking, the OS decides what programs will run, and for how long. Compare with Cooperative Multitasking. Preformatted Disk: See under Format. Printer: A device that attaches to your computer and prints things on paper. Printers vary wildly in image quality, speed, and price. Processor: The chip inside your computer, on the motherboard, that handles the processing of most of the data that travels through your system. It's the most important chip on a motherboard, and usually the largest. Program: 1. (noun) A software tool designed to let you do something with your computer. A program could be a thingy for drawing, a thingy for writing text, or a thingy for playing games, or something else. 2. (verb) To write programs on a computer. Programmer: A person who programs (definition 2). Programmers are, almost without exception, hackers. Proxy Server: A computer which serves as a gateway between computers or networks. Usually, proxies are used in LANs to join the LAN to the Internet (or another network). Proxies are usually used as a security measure. Proxies which are mostly for security are called firewalls. (The terms "proxy server" and "firewall computer" are sometimes used interchangeably, even though technically speaking, a firewall is a specific type of proxy, and not all proxies are firewalls.) Proxies can also be used to provide several computers access to one network access point. For example, on a dial-up Internet connection, only one computer at a time can actually use the phone line, but a proxy server could be used to provide several computers with access to the same connection. (The proxy would be be physically connected to the phone line, and all the other computers would connect to the proxy and get the Internet access through it.) In addition to connection sharing and security, a proxy server can have a third purpose: Caching. Some proxies store frequently- accessed websites in memory, so that whenever a computer on the LAN requests it, the proxy can immediately retrieve it without actually having to go out and download it from the Internet. If some sites are very frequently-accessed, this can significantly speed things up. Proxies which do this are also called cache servers. PSN: Packet-Switched Network. A type of network (the Internet being the world's largest example) in which information is not sent as a whole, but is instead split into smaller bits of information (knows as "packets"), and then sent out in many packets, which are re-assembled upon hitting their destination into the information they're supposed to represent. The Internet's protocol for packet transmission is IP. Pull-Down Resistor: A resistor which works much like a Pull-Up Resistor, but in reverse: It connects a particular point to the negative side of the power supply at a point which might be joined to the positive end. Pull-Up Resistor: A resistor used on an "open collector" part of a circuit to draw it up to a particular voltage. In a case where the particular part of a circuit may be directly joined to the negative side of the power supply, to directly connect that part of the circuit to the positive end would result in a short-circuit; In these cases, a pull-up resistor is used, which is simply a resistor between the positive end of the power supply, and the location where a higher voltage is needed. The resistor result in a gentle rise to the desired voltage, providing enough resistance to avoid damage caused by a short circuit. See also Pull-Down Resistor. PUN: Physical Unit Number. A number assigned to a physical device on a SCSI chain. Up to eight such devices can be attached to one SCSI bus. PUNs are much more commonly called "SCSI IDs", but the term PUN may be used to distinguish from LUN. PUNs (SCSI IDs) are numbered from 0 to 7. Normally, the SCSI host adapter takes SCSI ID 7 for itself. See also LUN. Punch-Down Block: A device for connecting wires which uses metal teeth that are punched into the wire; The teeth pierce the insulation, making contact with the wire's conductor and thusly they are connected. Most often used with telephone wiring and other forms of twisted-pair wiring. Because they are not often designed to be connected and disconnected repeatedly (which is something you must allow for in a network environment), punch-down blocks are generally eschewed, and patch panels preferred, when working with LANs. QA: Quality Assurance. A company department. Radix: The next-highest number from the highest single-digit value that exists in a number system. This is the point where the digit rolls over to zero and the digit in the next column to the left is incremented. For example, in the common, everyday decimal number system, the radix is 10. Below 10 is 9, which is the highest single-digit number. Increment 9 and you get 10, which is the result of resetting the digit which held "9" to zero, and incrementing the next column to the left. In hexadecimal, the radix is 16. In octal, the radix is 8. In binary, the radix is 2. Radix is often referred to as "base", for example, "base 10" for decimal or "base 2" for binary. RAM: Short for Random Access Memory. RAM is the computer's internal workspace, where it stores all info about what's going on right now. Anything stored in RAM is lost when you shut off the computer, so before turning it off you must transfer the data in there into a place where it can be kept for longer, such as a disk. One of the most common questions people ask about RAM is "Why is it called random-access?" Most people know what RAM is by now, but few seem to understand why it's actually called by its name. After all, access to RAM isn't random. If it were, how would you know what data you were getting from it? Quite to the contrary, access to RAM is very organized. The answer is that it *can* be accessed randomly. Any program can access any part of RAM at any time. It can do so randomly if it so wishes, but most programs don't. The term was actually originally used to distinguish from tape storage drives, which are notoriously slow because they store data on a long strip of media, which takes a long time to spin around to the various storage positions. RAM was dubbed "random-access" because any program could randomly jump to any part of it. Because of the confusion over the so-called "random" nature of RAM, IBM sometimes has preferred to use the term "direct access memory" (DAM). Other people refer to RAM more specifically as "read/write memory", as distinguished from ROM. RAMDAC: Random Access Memory Digital-to-Analog Converter. A RAMDAC is most often used in a computer's video card, where it is used to convert the contents of the video RAM (where the screen image is stored) from digital data into an analog signal (since most computer monitors are analog). RAS: 1. Row Address Strobe. Compare CAS. 2. Remote Access Server. 3. Remote Access Service. Raster Burn: An eye disease hackers get from staring at a computer monitor for too long a time. Often shows up during hacking runs. R&D: Research And Development. A company department. RDBMS: Relational Database Management System. RDRAM: Rambus Dynamic RAM. Reboot: To start your computer over from the beginning. This is usually done either by pressing the RESET button on the front of your computer (if there is one), or by pressing CTRL, ALT, and DEL on your keyboard together. Rebooting is usually done either when you have made changes to your computer configuration (rebooting is necessary for configuration changes to take effect), or when the computer locks up. REFIID: Reference Interface ID. A 16-byte value which identifies a reference interface. A type of GUID. Remote: On another computer which you're connected to via a network. This term is often used with phrases like "remote access", which means accessing a computer other than the one you're at right now (over the network). Remote is the opposite of local. Reset: To reboot with the RESET button. Resolution: A measure of the number of pixels per row and per column in an image. For example, an image with a resolution of 320x200 has 320 horizontal pixels, and 200 vertical ones. The term is used to apply to screen modes, image file sizes, etc. The higher the resolution, the clearer the image (and the more data needed to store it). Ring: 1. A network topology in which workstations are arranged in a circle, with each being connected to two neighbours. Used with Token Ring, FDDI, and similar protocols. 2. Commonly-used term for what is more properly (and distinctly) known as an IOPL (I/O Privilege Level). RIP: Routing Information Protocol. A routing protocol. Specifically, an IGP. Rising Edge: A transition from a logic 0 to a logic 1. Also called positive edge. RMS: 1. Root Mean Square. Used a lot when talking about speaker voltages. (Which means that the power rating applies to *each* audio channel, rather than the total power of all channels.) 2. Richard M. Stallman, famous for being founder of the GNU Project and for writing EMACS. ROM: Read-Only Memory. Memory which cannot be written to, only read from. (Hence the name: It's not memory you can WRITE to, you can only READ it: READ ONLY memory.) Root Directory: The central directory of any disk. Any directories on a disk are actually subdirectories of the root directory. The root directory usually doesn't contain much except directories, system files, and a few other files which don't really fit into any other directory. Rotary Modem: A modem which works on a rotary, which in turn is a phone number that connects to more than one phone line. ISPs use rotary modems so that users can all call the same number, but each gets a different modem. Rotoscoping: A technique to make realistic-looking animation by capturing a series of still-image shots and stringing them together, similar to the way those "claymation" movies are made. Rotoscoping was extensively used in computer games in the mid-1990s to create characters that animated smoothly, but was eventually overtaken by the pure-3D graphics revolution which uses polygon-based objects rather than flat sprites. Route 128: The famous road running through the Boston, Massachusetts area on which many large computer companies placed their headquarters. By far the most famous of these was Digital Equipment Corporation (DEC), but there were many others, including Wang Laboratories, Prime Computer, Data General, Apollo, Computer Control Corporation, and Computervision. In the days when the computer revolution was still in its infancy, Route 128 was the east coast's counterpart to Silicon Valley. Routing Table: A table stored within a router which tells it where to send packets it receives. A routing table contains two basic items for each entry: Address, and exit interface. The "exit interface" is the path which the router should send a packet to get it one step closer to its destination. A router does not really know where the target computer is, nor does it care; The router is only one link in the chain, and its only job is to know where to send the packet next. The routing table lets it know exactly where to send packets for each address on the network. As an example, suppose a router receives a packet with a destination IP address of 1.2.3.4. The router checks its routing table, and finds that the exit interface specified for 1.2.3.4 is line 3. Because of this, the router sends the packet down line 3, probably to another router, which will be one hop closer to the destination. In many cases, the router does not hold complete IP addresses in its table, but rather network domains. In the above example, the router might not have an entry specifically for 1.2.3.4, but rather a network entry specifying that all traffic to addresses beginning with 1.2.3 should go to line 3. RPI: 1. Rockwell Protocol Interface. A modem protocol interface. 2. A type of modem which uses RPI. RPI modems are similar in concept to what are commonly called "Winmodems" today (though RPI modems precede Winmodems by a few years). RPI modems require software to run; In other words, they are not completely hardware-based modems, using software to do some of the processing that's usually done by chips on the modem. This is done solely to reduce the price of the modem (by about $5). RPM: 1. RedHat Package Manager. A compression format used by Red Hat Linux. 2. (in car racing games) Revolutions Per Minute, the same thing as in real-life car racing. RTL: Resistor-Transistor Logic. One of the earliest IC logic families. Now obsolete. See also DTL, TTL, and CMOS. S-100 Bus: A very old type of bus which absolutely nobody has on modern computers and which most people have never even heard of. (It was used on the Altair 8800.) SAM: Synchronous Address Multiplexer. SAN: Storage Area Network. A network of data storage devices, usually connected to a more general-purpose network. Sand Hill Road: A road in Silicon Valley, famous for its concentration of venture capital (VC) companies. This is significant to Silicon Valley, since the Valley tends to run on startups with plenty of ideas but a need for money to put those ideas into action. Thus, Sand Hill Road has become a local icon, the fabled place where dreams become reality. SAPI: Speech Application Programming Interface. SC Connector: "Subscriber Connector", a type of fiber-optic connector which directly connects two components together. Schmitt Trigger: A handy electronic circuit used to "clean up" noisy signals for use with a digital circuit. The Schmitt Trigger has two certain threshold voltages which dictate at what point its output will go to a digital high, or a digital low. For example, suppose the Schmitt trigger's "high" threshold is 80 volts and its "low" threshold is 20 volts. If the input voltage starts at 0 volts and goes to 50 volts, the output will remain low. Only when the input goes above 80 volts will the output go high. However, if the voltage then drops to 50 volts again, the output will remain high; Only when the input goes below 20 volts will the output go low again. Schmitt Triggers are widely used to dampen "switch bounce" for digital circuits or to stabilize waveforms which exhibit fluctuation. Not to be confused with Schottky Diode. Schottky Diode: A type of diode notable mainly for its very high speed. This high speed makes it popular in logic circuits where fast, precise timing is required. Schottky diodes also have a remarkably low forward voltage drop, meaning that it will not reduce its forward-direction voltage much (as opposed to zener diodes (the other popular type of diode), which may reduce their forward voltage more). "Schottky" is pronounced "shot-key". Not to be confused with Schmitt Trigger. SCO: Santa Cruz Operation. A company that makes a type of UNIX. Screen: The screen is the glassy part of the monitor. "Monitor" refers to the entire big box as a whole, but the screen is just the glass at the front. SCSI: Small Computer System Interface. Pronounced "scuzzy". SCSI is basically made a big deal out of for two reasons: First, it is fast (and of course speed is essential to the computer industry). Secondly, its much- hyped ability to let you attach several devices (up to 8 of them) to a single SCSI chain which then connects to a single port on the computer. This combination of high speed with multiple device connectivity made SCSI the ancestor of USB. Indeed, SCSI wanted to be the global standard that USB ended up being, but SCSI was killed by several important problems: First and foremost was the very high cost of SCSI adapters, cables, and peripherals. Second was a strange lack of standardization that meant devices made to work with SCSI did not necessarily work with every SCSI-using computer, whereas USB was standardized to the point where just about any USB peripheral will work with just about any USB-supporting computer. There was also a lack of robustness in the mechanics of SCSI that made it rather flaky in nature, and difficult to expand because it needed very short cables. And finally, unlike USB, SCSI was definitely not plug-and-play. Each SCSI device needs its own unique ID on the chain, which is usually configured through a jumper. Although this is not really a big deal, it's too much trouble for the casual computer user, who would really rather just plug something in and have it start working right away, … la USB. SCSI may never have become a household acronym had it not been for Apple's support of it as a way to expand the rather closed-ended Macintosh. SCSI was an important element in the development of the PC industry, but ultimately it never stopped being a niche product. SCUMM: Script Creation Utility for Maniac Mansion. A scripting language designed by Ron Gilbert and used in many Lucasfilm/LucasArts adventure games, beginning with their classic Maniac Mansion (for which it was originally designed) and later several others, including the celebrated "The Secret Of Monkey Island". SDRAM: Synchronous Dynamic RAM. A new, fast type of RAM which has recieved a lot of hype. It can handle bus speeds of up to 100 MHz (which is impressive), and it is synchronized with the computer's system clock itself, a feat which had previously eluded computer engineers. Sector: An area on a disk which is usually 512 bytes. They are organized into clusters, which are the smallest unit of space that can be allocated to a single file. (No, you can't allocate a single sector, except on some floppy disks which use single-sector clusters.) Shadowing: The practice of copying the contents of the BIOS ROM into part of RAM when the computer boots. This is done to speed things up, as RAM is usually two or three times faster than ROM. Shareware: Software which can legally be copied from one computer to another. However, shareware is not "free" software. If you get shareware and you like it and decide to keep it and continue to use it, the person or people who made the program ask that you send them money for it. Shareware can quite legally be put available for download on the Internet, and thrown all over the place on disks. That way, you can download it in the comfort of your own home, and you don't have to get up to go to a software store to buy anything. Another advantage of shareware is, it lets you try the program BEFORE you buy it, so there's no chance of buying a program and discovering it's not for you (something which is very possible with store-bought software). One disadvantage to shareware is that it is somewhat prone to being virus- filled. After all, shareware passes through many hands because it costs nothing, so if a friend of yours gives you a disk with shareware, you never know what other computers that disk has been in. Another little problem with shareware is that most of it (or at least, a lot of it) is garbage. Any goof who can program can write up a little program which is incredibly lame, and ask $5 for it. Many people release some of the most impossibly dumb programs into the shareware world. That's why shareware is often worth exactly what you pay for it: Nothing. However, there are some people who go to the trouble of writing really excellent shareware programs, in the hopes that at least a few people will be honest enough to send the requested $10 or whatever, instead of ignoring the money requests and just using the program without paying. See also Freeware. shellcode: [Unix] Machine-language code which is directly inserted into memory to get the computer to run it. This is almost always done as a cracking technique, to get the system you are attacking to do something it would not normally let you do. Generally, the machine-language code is stored in an array, and the array is somehow inserted into memory using pointer variables. Shellcode is closely related to buffer overflows (because buffer overflows are usually the method used to insert the shellcode into memory). As such, they are documented in the classic buffer-overflow tutorial file, "Smashing The Stack For Fun And Profit", by Aleph One. Briefly, the method to getting shellcode to run works like this (the following was actually borrowed from Mr. One's fine file): char shellcode[] = "(YOUR SHELLCODE HERE!)"; void main() { int *ret; ret = (int *)&ret + 2; (*ret) = (int)shellcode; } Shell Script: A series of Unix shell commands, put into a text file and run collectively as a program. Basically what MS-DOS users would call a "batch" file. SID: Sound Interface Device. A term used for the built-in sound chip on old computers such as the Commodore 64. Signed: (in programming, of an integer variable) Having a plus or minus sign attached to it to indicate whether the integer is positive or negative. A signed variable can be either positive or negative. See also Unsigned. Silicon Valley: 1. The Santa Clara Valley in California between Palo Alto and San Jose near the San Francisco bay area, about 40 miles southeast of San Francisco in Santa Clara County, consisting chiefly of the cities of Cupertino, Milpitas, Mountain View, Palo Alto, San Jose, Santa Clara, and Sunnyvale, as well as less significant cities like Campbell, Fremont, Menlo Park, and Stanford, and possibly including the offshoot areas of Santa Cruz and San Mateo, through which highway 280 North runs west and 680 North runs east (that highway, along with US101 (the Bayshore Freeway as it's called there, which also goes all the way south to Los Angeles), joins the Valley to San Francisco County). Nearest airports: San Jose International Airport, Palo Alto Airport Of Santa Clara County, and Moffett Federal Airfield in Mountain View. So named because of its extremely high concentration of electronics/computer companies (from the silicon in computer chips). Contains a host of some of the largest and most important companies in the computer industry. The biggest are (city names in parentheses): Apple (Cupertino), Sun Microsystems (Palo Alto), Intel (Santa Clara), Oracle (Redwood Shores), Adobe Systems (San Jose), Inprise (Formerly Borland International) (Scotts Valley), Hewlett-Packard (Palo Alto), Silicon Graphics Inc. (Mountain View), Maxtor (Milpitas), Creative Labs (U.S. Headquarters in Milpitas), Yahoo! (Santa Clara), AltaVista (Palo Alto), Netscape Communications (Mountain View), Excite (Redwood City), Infoseek (Sunnyvale), 3Com (Santa Clara), Cisco (San Jose), Adaptec (Milpitas), Zilog (Campbell), Award Software (Mountain View), ABIT Corp. (Fremont), VIA Technologies (Fremont), Trident Microsystems (Mountain View), S3 (Santa Clara), National Semiconductor (Santa Clara), Cirrus Logic (Fremont), Chips & Technologies (San Jose), Oak Technology (Sunnyvale), 3Dfx (San Jose), nVidia Corporation (Sunnyvale), VESA Standards (San Jose), Samsung (San Jose), Advanced Micro Devices/AMD (Sunnyvale), VLSI Technology (San Jose), Diamond Multimedia Systems (San Jose), Fujitsu (San Jose), Hyundai (San Jose), Wyse Technology (San Jose), Electronic Arts (San Mateo), Symantec (Cupertino), Santa Cruz Operation (SCO, the SCO-UNIX company) (Santa Cruz), Phoenix Technologies (San Jose), Network Associates (Santa Clara), Intuit (Mountain View), McAfee Associates (Santa Clara), Acer (San Jose), Plextor (Santa Clara), MediaVision (Fremont), PCMCIA (Yes, the company that sets the PC Card standards) (San Jose), Seagate (Scotts Valley), and Syquest (Fremont). (Note, however, that contrary to what some people may believe, Silicon Valley is not just a big gathering of computer companies. People still need to live there, and so it has many large residential districts, along with the kind of mainstream businesses that every city needs. Silicon Valley may have more computer-related jobs, companies, and people than any other region in the world, but even computer people need places to sleep and buy other necessities of life.) See also Route 128. 2. (from this valley) The computer industry in general. 3. Any place (either an actual physical location or a chat room or similar area in cyberspace) where computer enthusiasts gather. SIMM: Single Inline Memory Module. A type of RAM module which has 30 or 72 pins. They must be installed in pairs (i.e. you can't have an odd number of them in your computer). They used to be the most popular form of memory module, but have now been replaced by DIMMs. Simulation: A Simulation Game. Simulation Game: A game which simulates something. The most common type of simulation is a flight simulation (which simulates flying an airplane or helicopter or something like that), but there are also car simulators, boat simulators, tank simulators, and simulations of lots of other things, too. SIO: Serial Input/Output. (As opposed to parallel I/O.) SLIP: Serial Line Internet Protocol. A common but somewhat outdated protocol for establishing dial-up connections to the Internet. Technically, SLIP is a "packet-framing" protocol that defines how IP datagrams (Internet data packets transmitted with IP) are packaged for transmission over serial data lines (usually the one between your computer's modem and your Internet service provider). See also PPP. Slot: Usually-used term for Expansion Slot. SMART: Self-Monitoring And Reporting Technology. An advanced hard drive technology that allows the drive to monitor its own operation and predict most hardware failures before they occur. It can give you a warning shortly before disk breakdown. For SMART to work, the hard disk and the BIOS must both support it. SMP: Symmetric Multiprocessing. SNMP: Simple Network Management Protocol. Socket: A hole which you plug something else into. SO-DIMM: Small-Outline DIMM. A type of DIMM with a small size, used for portable computers. Soft Copy: See Hard Copy Software: The non-physical parts of your computer (your programs and data). Compare with hardware. When you buy programs at a computer store, that's software... But you're actually buying the computer disks, aren't you? And disks are an actual, physically real thing aren't they? Well, yes, and you are paying for the disks, too, but the majority of the price of software is the data. So while you are buying hardware as well (the disks), mostly what you're paying for is the stuff on those disks. Software Piracy: See Piracy Software Pirate: See Pirate Software Program: Program (definition 1) SOIC: Small Outline Integrated Circuit. The type of chip profile used for surface-mount chips. (As opposed to DIPs, which are through-hole-mount chips.) Solder Flux: A substance used in soldering which serves two purposes: First, it cleans the surfaces to be soldered to promote a clean bond. Secondly, it promotes even flow of the solder itself, resulting in a smoother solder joint. (Technically, it improves the "wetting" of the solder, which is the tendency of the solder to flow over surfaces rather than sticking to itself in a solder ball.) Solder flux may be applied separately before soldering is performed, or it may be blended in as part of the solder itself. Sound Card: A card which serves to produce sound. Used because the IBM PC has no sound system other than the extremely poor-quality internal speaker. SPICE: Simulation Program with Integrated Circuit Emphasis. A computer program used to simulate electronic circuits. Although there are several programs which do this, SPICE is generally considered the most prestigious and powerful, the Cadillac of circuit simulation programs. Sports Game: A computer game which is about sports. SPX: Sequenced Packet Exchange. A LAN protocol. SPX works on top of IPX and adds extra commands. In the OSI model, SPX conforms to the transport layer. SQE: Signal Quality Error. Square Wave: An electrical wave which has only two levels, and very rapid (near-zero) rise and fall times. Square waves are often seen in digital electronics, since digital electronics use only two voltage levels, one for a logical high and one for a logical low. Square waves are so named because they form a distinctive pattern of square or rectangle shapes when viewed on an oscilloscope, as opposed to the curvy sine- wave pattern typical of analog electronics. SRAM: Static RAM. Like DRAM, except that while DRAM constantly updates, SRAM never gets refreshed except if it happens to get written to. SRAM is much faster than DRAM, but also much more expensive. It's usually used only as Level 2 cache memory. SSL: Secure Sockets Layer. A widely-used protocol to secure connections over the World Wide Web. SSL uses public-and-private-key encryption for fairly secure security. It is commonly used on e-commerce websites to secure private information like credit card numbers, etc. Status Message: An onscreen message informing you of the status of something to do with your computer. ST Connector: Straight Tip connector, the standard type of connector used for plugging in fiber-optic cables, as well as for joining together lengths of fiber-optic cable to extend their length. Strategy Game: Nearly every computer game will involve some form of strategy, so all games can really be considered strategy games to some degree, but the term "Strategy Game" is usually used as a category for games which don't really fit too well in any other category, or those which are PURELY strategy. Subdirectory: A directory inside a directory. Yes, directories can hold other directories as well as files. Superconductor: A substance that conducts electricity well. Support: A mythical thing which does not exist in the computer world but which is often spoken of in fearful tones. SX: A type of chip made by Intel (either a 386SX or a 486SX) which has the math co-processor masked off. Sometimes called the "brain dead" equivalents of the fully-functional chips, these were failed attempts to make a cost-effective processor. The opposite of DX. System: A computer. Used when saying "computer" would be repetitive or uncool. System Files: Files which the computer needs to get itself started. These files are kept in the root directory, and contain critical operating system info. If these files are erased, your computer won't work. If you're using MS-DOS, your system files are IO.SYS, MSDOS.SYS, and COMMAND.COM. TAPI: Telephony Application Programming Interface. TCP: Transmission Control Protocol. A protocol (besides IP) used on the Internet. TCP is in layer 4 (the Transport layer) of the OSI model. Terminal: 1. Synonym for computer. 2. A small computer which is hooked up to a network and is, for the most part, a slave to a server somewhere. Text: A collection of characters (words, numbers, etc.) The words on your computer screen are text, the words in a book are text, just about everything that's writing is text. TFT: Thin-Film Transistor. A type of LCD display which a transistor for each pixel on the screen. This means that the pixels can be turned on or off more quickly. TFT screens used to be called "active matrix" screens, but now the term TFT seems to be in fashion. Such screens are better than "passive matrix" screens (which do not have a transistor for every pixel), because on passive-matrix screens it takes a while to update a pixel, which leads to effects like "mouse trails" in which the mouse pointer seems to leave "ghost" pointers behind it as it moves. Passive matrix displays are now called DSTN, which has replaced "passive matrix" much like TFT has replaced "active matrix", proving that it's fashionable to use acronyms rather than terms which make sense. Thermistor: A resistor which varies in resistance according to its temperature. (Usually, as the temperature rises, the resistance is reduced.) Tilde: The squiggly line ~ character, found next to the 1 at the top of most keyboards. Used mostly for some Internet addresses and DOS storage versions of Windows 95 long filenames. Time Bomb: 1. A computer program (usually a virus) which is set to go off at a certain time. When that time comes, whatever the program does when it's triggered will depend entirely on the program itself. Many famous viruses have been programmed to go off on particular dates, like Friday the 13th, or every Sunday. See also Logic Bomb. 2. A demo of a full-version program which is scheduled to stop functioning when the user's trial period has expired. A lot of commercial software is available in demo versions these days, and most of the demos give you only a specific time frame (like 30 days) before they stop working, to encourage you to buy the full program. TLA: Three-Letter Acronym. See also AWFL. TLD: Top-Level Domain. Examples: .com, .net, and .org. TOC: Table Of Contents. Toggle Switch: A switch which stays where you set it. A button which stays in when you push it, and must be pushed again to have it pop back out, is a toggle switch. Compare Momentary Switch. Torvalds, Linus: A Finnish guy who created Linux. Later went on to work for Transmeta Corp. in Santa Clara, California. TOS: 1. Terms Of Service. 2. Type Of Service. Transistor: The word "transistor" initially comes from "transfer resistor". Tray Card: 1. A template of paper format used for the back covers of CD jewel cases. See also J-Card. 2. A sheet of paper printed using this template. Tri-State: (Of a logic component) Having an input which can disable the component so that it produces no output. For example, a NOT gate has two inputs. If the tristate control is on, then the NOT gate will produce a low output if the input is high, and a high output if the input is low. However, if the tristate control is off, then the NOT gate will not produce any output at all. TSR: Terminate-And-Stay-Resident Program. TTL: Transistor-Transistor Logic. A wildly popular IC logic family for many years. TTL devices usually have 7400/74000 series numbers. They may also have 5400/54000 series numbers, which are generally functionally equivalent, but able to meet military specifications. For example, a 5400 chip is basically a heavy-duty 7400 chip. See also RTL, DTL, and CMOS. Turbo Mouse: Older term for a trackball. Typeface: Font. Type Mismatch: A programming error in which an attempt is made to have two variables operate together which are of an incompatible type. This is a common error when trying to operate on a string variable with a numeric variable, or vice-versa. For example, the command "a% = a$" gives a type mismatch error in BASIC, because the % suffix indicates a numeric variable, while $ indicates a string variable, and you cannot set a numeric variable to be a string. A type mismatch can also occur with constants; For example, the command "a% = "Hello, world!"" also gives a type mismatch, because it attempts to assign a string value to a numeric variable. UART: Universal Asynchronous Receiver-Transmitter. UDF: Universal Disk Format. UDP: User Datagram Protocol. A protocol sometimes used on the Internet, which rides on top of IP in much the same way as TCP does. UDP, however, is connectionless (it only send packets, without establishing a connection first, as TCP does), it doesn't sequence the packets as TCP does (meaning it can be tricky to make sure they arrived in the right order), and it doesn't even acknowledge sent packets (as TCP also does), meaning you can't really be sure they arrived in the first place. So why use UDP? In situations where speed is more important than making sure every byte arrives correctly, UDP is popular, because it is somewhat faster than TCP (because it doesn't send all the acknowledgement/sequencing data that TCP does). Thus, UDP is often used for media streaming (where a few blips in a video or audio sample won't make a huge difference), or online action gaming (where speed of data transmission is paramount). Why use UDP at all when you can use raw IP? Well, UDP does offer two features that plain IP doesn't: Ports (to distinguish different user services), and a checksum capability, so the system on the receiving end can at least verify that the data it's receiving didn't get corrupted. UMB: Upper Memory Block. Unformatted Disk: A disk which has not yet been formatted. Unicode: The successor to ASCII. Whereas ASCII is limited to only 256 characters (because it's 8-bit, and that's as many combinations as you can get from 8 bits), Unicode is a 16-bit character code, meaning it can support up to 65,536 different characters. This is more than sufficient to support every character in every world language used by humanity, including Oriental characters (Chinese, Japanese, Korean, etc.), Cyrillic, Hebrew, Arabic, and others, hence the name "Unicode": Only one computer character code needed to support every language in the world. UNIX: An operating system which is popular in the business sector. It is not very popular among home-based systems (except for people who use it at work, or who like to have their computer be hard to use) because of its difficult-to-learn commands and text-based interface. Despite this, it is favoured in the high-tech industry for its power and flexibility. Unsigned: (in programming, of an integer variable) Lacking a plus or minus sign to indicate whether the integer is positive or negative. Unsigned integers are always positive, and simply written without the plus sign on them. See also Signed. Upload: The opposite of download. Nobody ever does this, but BBS sysops tend to wish people would. User-Friendly: Easy to use. (No, it's not impossible to have a user- friendly computer.) Utilities: Plural of Utility. Utility: A software program which, rather than being designed to help you do something useful with your life such as calculate finances or write letters, is simply intended to help you use your computer. Utilities may delete files for you, check for viruses, or do a bunch of other things which are DIRECTLY related to computers. UUID: Universally Unique ID. A 16-byte value which identifies a type library and/or its individual components. A type of GUID. Van Jacobsen: Someone who did a lot of work on TCP. Jacobsen has been immortalized by having his method of TCP header compression named after him. Van Jacobsen (VJ) compression is also commonly known as CSLIP (Compressed SLIP). VCPI: Virtual Control Program Interface. A specification for managing extended memory or expanded memory (i.e. memory beyond the first megabyte of RAM) on DOS computers. The MS-DOS expanded memory emulator EMM386 is a VCPI server. VDG: Video Display Generator. An ancient name for what is today simply called a video chip. Vectorscope: An electronic measurement instrument similar in form to an oscilloscope, but intended specifically for reading the chrominance (colour signal) of a video signal. Verilog: An HDL (Hardware Description Language). Originally created as a commercial product, Verilog is now maintained by OVI (Open Verilog International), a not-for-profit organization. Verilog source files are designated by a .v extension. See also HDL, VHDL. VESA: Video Electronics Standards Association VFAT: Virtual FAT. A file system introduced in Windows 9x and marked chiefly by the advantage of supporting LFNs (Long Filenames) while still maintaining backward compatibility with MS-DOS. VFAT stores its long filenames as additional directory entries, and these entries are given a combination of attributes which are not possible for normal files: Read-only, hidden, system, and volume label. This causes DOS to ignore those long filename entries. VGA: Video Graphics Array. (Not Video Graphics Adaptor, as you might expect after MDA, CGA, and EGA.) VHDL: VHSIC Hardware Description Language. An HDL (Hardware Description Language). VHDL source files are designated by a .vhd or .vhdl extension. See also HDL, Verilog. VHSIC: Very High Speed Integrated Circuit. VIA: Versatile Interface Adapter. An old name for an I/O chip. This term was used with reference to computers like the Commodore 64. VIC: Video Interface Chip. An old name for the video chip. This term was used with reference to computers like the Commodore 64. Video Card: The card which controls everything you see on your monitor. VJ: See Van Jacobsen. VLB: VL Bus. VL Bus: VESA-Local Bus, and older type of local bus which has now been replaced by PCI. VLF: Very Low Frequency. In the range of 2 KHz to 400 KHz. Voice Recognition: Can be used as a noun, to refer to the ability of a computer to recognize and understand spoken words, or as a verb, to describe the action of a computer recognizing speech using voice recognition. VPN: Virtual Private Network. VRAM: Video RAM. A type of RAM which is specifically used to try and improve video performance and is usually used only for the memory on video cards (not main system memory). VXD: Virtual Device Driver. A lot of virtual device drivers have VXD for their filename extension. WAN: Wide-Area Network. A computer network which is big. The Internet is the world's largest WAN. Compare with LAN. Wannabee: A person who isn't a hacker, but wants/pretends to be. Wannabees overuse computer slang and thus quickly identify themselves. WAP: Wireless Application Protocol. Warez: Copyrighted software which has been pirated, or which is available for others to pirate. War Game: A computer game which simulates war. WDT: WatchDog Timer. White-Hat Hacker: A "cracker" hacker who hacks not to do damage, but to uncover security holes and report them (usually either to the company responsible for them, or to mailing lists like Bugtraq, or both). Compare Black-Hat Hacker. William (Bill) Gates: See Gates, Bill. Windows: See Microsoft Windows. Winmodem: A modem which requires Windows to work. "Winmodem" is actually a registered trademark of U.S. Robotics for a particular line of modems they manufacture, but the term Winmodem is more frequently used to refer to modems which require Windows. See also Linmodem. WINS: Windows Internet Naming Service. A naming system similar to DNS: It assigns names to IP addresses of computers, and keeps track of them so you don't have to remember a computer's IP to connect to it, just its name. WINS is part of Windows NT Server. Winsock: Refers to WINSOCK.DLL, which is the Windows DLL for TCP/IP (Internet) stuff. The 32-bit version of WINSOCK.DLL comes with Windows 95. There was also a 16-bit version of it (for earlier versions of Windows), but that version didn't come with the earlier versions of Windows; You had to get it elsewhere (usually from a friend who had it). Wintel: Refers to Microsoft and Intel collectively, and their domination of their respective markets. Word: (in assembler programming) Two bytes, or 16 bits. Word Processor: A program that lets you type in stuff. Workstation: A client on a LAN. WPA: Windows Product Activation. First introduced in Windows XP, WPA is a "feature" of Windows that requires the OS to be registered with Microsoft. (If it is not registered with Microsoft after a certain time period, the OS will stop working.) WPA records several aspects of hardware configuration in its database, to prevent someone from installing the same copy of Windows on two different computers. Although it has always been illegal to use the same copy of Windows on different computers (if you own two computers, you're supposed to buy two copies of Windows), before Windows XP, there was nothing preventing people from doing so. WRAM: Windows RAM. A type of RAM which is a lot like VRAM, and used for the same thing, but WRAM is somewhat faster. WYSINWYG: What You See Is Not What You Get. The opposite of WYSIWYG. WYSIWYG: What You See Is What You Get. This is a condition that means what appears on the screen will appear the same when it's printed out on the printer. Pronounced "wizzywig". X.25: A data transmission standard which has been largely superseded by frame relay. (See Frame Relay.) XML: Extensible Markup Language. A language for the WWW, essentially the successor to HTML. In terms of end-user benefits, XML offers nothing, as an XML document looks the same to the user as HTML. However, XML allows you to put "structured data" into a document. Perhaps not surprisingly, XML documents have an .xml extension. XMS: eXtended Memory Standard XT: eXtended Technology