Internet Glossary
A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z


A



address
(a) Usually refers to an Internet machine name; for example, www.ocsny.com.
(b) The name you use to say who is supposed to receive an electronic-mail(email) message. An email address consists of the person's user name and, if the person is on a different computer than you are, the name of the computer.

absolute address
An URL that includes the full Internet address of the machine on which the HTML file resides; for example, http://www.ocsny.com/~username/index.html.

AFS
A set of protocols that allows you to use files on other network machines as if they were local to your own machine. So, rather than using FTP to transfer a file to your local computer, using AFS you would be able to read it, write it, or edit it on the remote computer while using the same commands you would use locally. Very similar in concept to NFS, though it provides better performance. AFS is not yet in widespread use, but a commercial version is currently available from a company called Transarc.

AIX
IBM's version of UNIX.

alert
Pop-up window that displays a message to the user. The user must click the "OK" button to proceed.

anchor
A location within an HTML document that is invisibly "marked" with HTML tags. Links can point to this anchor, and take the user to specific locations within one HTML document.

anonymous ftp
Uses the ftp file transfer program and the Internet to copy files from other computers to your own. It is anonymous because many computer systems allow anyone to log in and transfer files without having accounts (user names) on the computer. You type anonymous as the user name and your email address as the password.

applet
Another name for a Java miniprogram. Applets are the Java elements that are run through Java-enabled browsers. In JavaScript, these are called "scripts" rather than applets.

application
(a) Software that performs a particular useful function for you. Examples being applications for email, world wide web browsing, etc.
(b) The useful function itself, e.g., transferring files is a useful application of the Internet.

archie
A system for locating files that are publicly available by anonymous FTP.

argument
Something that appears on a command line after the command. Suppose you type this line:
cp old.file new.file
In this command, cp is the name oft he command or program, old.file is the first argument, and new.file is the second argument.

arithmetic operator
Any of the following symbols: * (multiply), +, -, / (divide), % (modulus), ++ (increment), -- (decrement), or - (negation). Arithmetic operators are used with variables or numeric values in an expression, to yield a mathematical result.

ARPAnet
An experimental network established in the '70s where the theories and software on which the Internet is based were tested. It is no longer in existence.

ASCII
American Standard Code for Information Interchange. ASCII defines the codes the computer uses internally to store letters, numbers, punctuation, and some control codes. Almost all UNIX computers use ASCII (except for some mainframes).


B



background
(a) UNIX can run many programs at the same time. If a program runs behind the scenes, with no interaction with you, it runs in the background.
(b) On World Wide Web pages, the images that lie behind the text and main images of the page. It can be a repeating pattern, a color, or just the default gray color.

backup
A spare copy of your data to keep on the shelf just in case. If you (or a coworker) delete a file by mistake or if parts of your computer break, you will be inexpressibly happy and smug if you have recently made a backup copy of your important files.

baud
When transmitting data, the number of times the medium's state changes per second. For example: a 14,400 baud modem changes the signal it sends on the phone 14,400 times per second. Since each change in state can correspond to multiple bits of data, the actual bit rate of data transfer may exceed the baud rate. Also see bits per second.

bin
A directory that contains programs on a UNIX system. Your home directory probably has a subdirectory named bin. The system has directories called /bin and /usr/bin.

BIND
The UNIX implementation of DNS. It stands for Berkeley Internet Name Domain.

bit
A tiny piece of information that can be either a 1 or a 0. Bits tend to get lumped into groups of eight bits, called bytes.

bits per second(bps)
The speed at which bits are transmitted over a communications medium.

Bourne Shell
The Bourne Shell is the most widely used UNIX shell. It prompts you with $. Its program name is sh.

BSD UNIX
A version of UNIX developed and distributed by the University of California at Berkeley. BSD stands for Berkeley Software Distribution.

BTW
Common abbreviation in mail and news, meaning by the way.

buffer
A small storage area in which information is stored temporarily until it is needed. Lots of things have buffers: printers frequently have buffers to store the next few lines or pages to print; emacs (a text editor) refers to its copies of the files you are editing as buffers.

byte
Eight bits in a row. That is, a series of eight pieces of information, each of which can be either 1 or 0. A little higher math tells you that there are 256 different combinations of eight 1s and 0s. (256 is 2 to the 8th power). There are therefore 256 different values for a byte of information. Most computers use a system of codes called ASCII to determine what each pattern means. The combination 01000001 means A, 010000010 means B, and 00001010 means "end of the line, start a new one."


C



C
A programming language invented at the same time as UNIX, and in which nearly all UNIX programs are written. C is a great programming language for lots of reasons. C programs look a lot like random punctuation strewn across the page.

C Shell
The C Shell is a UNIX shell written to look like the C programming language, sort of. It prompts you with %. Its program name is csh.

CD ROM
(a) A computer disk that looks just like a music CD but contains data rather than music.
(b) The device in a computer that reads CD ROM disks.

central processing unit (CPU)
The heart of the computers, the part that does the thinking (such as it is). These days, in all but the largest computers, the CPU is contained entirely on a little, black chip the size of your thumb and that costs maybe $200. CPU chips are names by using numbers, like 68040 and 80486, by using acronyms, like SPARC, or made-up names like Pentium.

checksum
A number computed by glomming together all the characters from an entire file in a special mathematical way. If you are afraid that a file is going to change, perhaps getting messed up by being transmitted across noisy phone lines, you can calculate a checksum before and after transmitting it. If you get the same checksum, the file probably didn't change.

CISC
Complex Instruction Set Computer; a type of CPU (central processing unit) chip. Pronounced "kisk." The other kind of CPU is a RISC.

CIX
Commercial Internet Exchange; an agreement among network providers that allows them to do accounting for commercial traffic. Although it has been discussed a lot on the press, it's primarily a concern for network providers.

clicking
"Clicking with a mouse" means moving the mouse until the cursor is on the thing you want to select and then pressing and releasing the mouse button. If your mouse has several buttons, use the leftmost button unless otherwise instructed.

client
(a) A software application that works on your behalf to extract some service from a server somewhere on the network. Think of your telephone as a client and the telephone company as a server to get the idea.
(b) In the X Window System and its relatives, Motif and OPEN LOOK, a program that does real work, as opposed to a program that displays the results on-screen.

client-server architecture
A system (used by the X Window System) that enables a program (the client) to run on one machine while the program that displays its results (the server) runs on another machine.

command
A word you type to get UNIX to do something. Actually, the UNIX shell listens to the commands you type and tries to execute them. Some commands are things the shell knows how to do. Other commands are separated programs, stored in files on the disk. When you type a command, press Enter or Return at the end of the line.

command mode
When you use the ed or vi text editors on UNIX machines, you are either in command mode or input mode. In command mode, whatever you type is interpreted as a command.

compression
A way to shrink files so that they don't take up so much space. There are many different file compression programs that do this, such as pkunzip, compress, the GNU tape archive(tar), and others.

core
An old-fashioned term for "memory." In the '60s and '70s, mot memory consisted of thousands of tiny metal donuts, called cores, strung on arrays of teeny-tiny wires. Some UNIX enthusiasts still refer to memory as core.

CPU
See central processing unit.

current directory
See working directory.

current job
The job you most recently starts or stopped. When you use jobs command to list jobs, the current job is marked with a plus (+) sign.

cursor
The little indicator on your screen that shows where you are working. Its shape depends on the program you are using. It may be a blinking underscore, a box, an arrow, a little hourglass, a little pencil - almost anything.

D



daemon
A process that runs around on its own to see to some housekeeping task on a computer. Your computer, or some computer on your network, has a printer daemon whose job is to print things waiting in the print queue.

data
Information.

DDN
Defense Data Network; a portion of the Internet which connects to U.S. Military Bases and contractors; used for non-secure communications. MILNET is one of the DDN networks. It also runs the NIC, where a lot of Internet information id archived.

DECnet
A set of proprietary networking protocols used by Digital Equipment Corporation operating systems, instead of TCP/IP. these protocols are not compatible with the Internet.

dedicated line
See leased line.

DFS
For all practical purposes, another name for AFS. More specifically, DFS refers to the AFS implementation that's part of the OSF's DCE (Distributed Computing Environment).

dialup-up
(a) To connect to a computer by calling it up on the telephone. Often, dial-up only refers to the kind of connection you make when using a terminal emulator and a regular modem. For the technoids, switched character-oriented asynchronous communication.
(b) A port that accepts dial-up connections. ("How many dial-up ports on your computers?")

directory
A collection of files with a name. A directory can be compared to a file folder that contains one or more files. Directories can also contain other directories. You can think of a directory as a work area because one directory is always the current working director. Directories, particularly directories contained in your home directory, sometimes are called subdirectories.

disk
Typically, a round flat thing on which information, or data, is recorded in much the same way as you record stuff on a cassette tape.

diskette
A removable disk, also called a floppy disk.

display adapter
The thing inside your computer that lets it talk to your screen.

DNS
The Domain Name System; a distributed database system for translating computer names (like www.ocsny.com) into numeric Internet addresses (like 204.107.76.9), and vice-versa. DNS allows you to use the Internet without remembering long lists of numbers.

DoD
The (U.S.) Department of Defense, whose Advanced Research Projects Agency got the Internet started by creating the ARPAnet.

DOS
An operating system patterned in some ways after UNIX. DOS runs on PCs.

double-clicking
"Double-clicking with a mouse" means moving the mouse until the cursor is on the thing you want to use and then quickly pressing and releasing the mouse button twice. It takes some practice to get the two clicks fast enough but not too fast. If your mouse has several buttons, use the leftmost button unless you are instructed otherwise.

dragging
"Dragging with a mouse" means moving the mouse until the cursor is on the thing you want to drag, pressing and holding the mouse-button, moving the mouse until the thing is where you want to drag it to (with the button still down), and then releasing the mouse button. If your mouse has several buttons, use the leftmost button unless you are instructed otherwise.

dumb terminal
A terminal that has no processing power of its own. It usually doesn't have any nice options either, like mice or screens that can do graphics.



E



editor
See text editor.

electronic mail(email)
Typed messages sent on a computer network rather than on paper.

Ethernet
A kind of local area network. It's pretty confusing because there are several different kinds of wiring, which support different communication speeds ranging from 2 to 10 million bits per second. What makes an Ethernet an Ethernet is the way the computers on the network decide whose turn it is to talk. Computers using the TCP/IP are frequently connected to the Internet over an Ethernet.

executable file
A file that UNIX can run like a program. AN executable file can contain binary machine instructions the computer knows how to execute, or it can contain a shell script (a list of UNIX shell commands) that UNIX knows how to execute.

external command
A command the shell doesn't actually know how to do. Instead, a program is stored in a file with the same name as the command. If you type the ed command (to run the ed editor), for example, UNIX runs the program contained by a file name ed.


F



FAQ
Either a frequently-asked question, or a list of frequently asked questions and their answers. Many USENET newsgroups, and some non-USENET mailing lists, maintain FAQ lists (FAQs) so that participants won't spend lots of time answering the same set of questions.

file
A bunch of information stored together with a name. A file can contain text, programs, or data in any format.

file system
A set of files stored on a disk or on one partition of a disk. A file system has one root directory that contains files and subdirectories. These subdirectories can in turn contain files and other directories.

file transfer
Copying files from one computer to another.

filter
A small UNIX program used with input or output redirection. The most commonly used filters are the more and sort commands.

fixed disk
See disk.

flag
See option.

flame
A virulent and (often) largely personal attack against the author of a USENET posting. Flames are unfortunately common. People who frequently write flames are known as flamers.

floppy disk
A removable disk, also called a diskette.

folder
A file that contains email messages you have decided to save.

foreground
A program currently able to talk to your terminal. Compares to programs running in the background.

fork
When UNIX starts a new process, it does so by closing an existing process. The closing process is known in UNIX as forking.

followup
A response to a USENET posting.

Freenet
An organization to provide free Internet access to people in a certain area, usually through public libraries.

FTP
(a) File Transfer Protocol; a protocol that defines how to transfer files from one computer to another.
(b) An application program which moves files using the File Transfer Protocol.
(c) A file-transfer program that enables you to log into another computer and transfer files to and from your computer.

FYI
(a> A common abbreviation in mail and news, meaning for your information.
(b) A series of informative papers about the Internet; they're similar to RFCs, but don't define new standards.



G



gateway
(a) A connection between one network and another, usually networks of different types.
(b) A computer system that transfers data between normally incompatible applications or networks. It reformats the data so that it is acceptable for the new network (or application) before passing it on. A gateway may connect two dissimilar networks, like DECnet and the Internet; or it might allow two incompatible applications to communicate over the same network (like mail systems with different message formats). The term is often used interchangeably with router, but this usage is incorrect.

Gopher
A menu-based system for exploring Internet resources.

GUI
A graphical user interface. GUIs let you use the computer by pointing at things with your mouse rather than typing commands. The most common UNIX GUIs are Motif, OPEN LOOK, and the X Window System. GUIs are sometimes called windowing systems. The World Wide Web is basically one large GUI.


H



hardware
The physical components of your computer system, that is, the boxes. Your computer hardware may include the computer, terminal, keyboard, screen, modem, printer, mouse, trackball, disk drive and even a scanner.

header
The first part of an email message that contains the address of the sender and the recipient, the subject, and lots of other stuff.

hidden file
A file within a filename that begins with a period. These files do not appear on regular LS directory listings (in UNIX). Use ls -a to include hidden files in a directory listing.

home directory
In UNIX machines, the directory you start in when you log in, usually a subdirectory of /usr. You should keep your files in your home directory, or in subdirectories of your home directory.

Huffman coding
A clever method of compressing information (like the stuff in your files) so that it takes up less space.


I



IAB
The Internet Architecture Board; the ruling council that makes decisions about standards and other important issues.

icon
A little picture used in conjunction with a GUI. A well-designed icon is supposed to be an obvious, unmistakable symbol of whatever it stands for, occupy much less space than do the equivalent words, and be cute. In practice, many icons are peculiar little pictures with no obvious meaning.

IETF
The Internet Engineering Task Force; a volunteer group that investigates and solves technical problems, and makes recommendations to the IAB.

IMHO
Common abbreviation in mail and news, meaning in my humble opinion.

impact printers
Printers that work by hitting a ribbon against the paper. They're old-fashioned nowadays, but they still work.

inbox
See mailbox.

incremental backup
A backup copy of only the files that have changed since the last full backup.

Internet
(a) Generally (not capitalized), any collection of distinct networks working together as one.
(b) Specifically (capitalized), the world-wide network of networks that are connected to each other, using the IP protocol and other similar protocols. The Internet provides file transfer, remote login, electronic mail, news and other services.

input mode
When you use the ed or vi text editors in UNIX, you are in either command mode or input mode. In input mode, whatever you type is entered into the file.

I/O
Input and output, that is, information going into or coming out of a program, computer, or other computer-type device.

I/O redirection
See redirection.

IP
The Internet Protocol; the most important of the protocols on which the Internet is based. It allows a packet to traverse multiple networks on the way to its final destination.

ISO
The Internet Organization for Standardization; an organization that has defined a different set of network protocols, called the ISO/OSI protocols. In theory, the ISO/OSI protocols will eventually replace the Internet protocols. When and if this will actually happen is a hotly debated topic.

ISOC
The Internet Society; a membership organization whose members support a world-wide information network. It is also the governing body to which the IAB reports.

ISP
Common abbreviation in mail and news, meaning Internet Service Provider


J



job
A program you started from the shell that can start, stop and move between foreground and background.


K



K (also KB or kilobyte)
A measure of memory or disk size which is 1,024 bytes of information. This number happens to be 2 multiplied by itself 10 times, which is a nice round number for computers.

keyboard
The thing you type on to tell your computer what to do. there are many different keyboards, with a wide variety of keys on them.

kill
To stop a process from running.

kludge
A program or feature that works but that the author is embarrassed about. Rhymes with "huge," not with "fudge." Sometimes misspelled as kluge.

Knowbot
An experimental information-retrieval tool; a robotic librarian.

Korn Shell
An enhanced version of the Bourne Shell, written by a guy named Korn. It prompts you with a $. Its program name is ksh.


L



laser printer
A printer that works like a photocopying machine, except that, rather than a paper original, the information to copy is drawn on the drum by a laser.

Leased line
A permanently-connected private telephone line between two locations. Leased lines are typically used to connect a moderate-sized local network to an Internet service provider.

line editor
A text editor that deals with text one line at a time. Most modern text editors let you see and work with the file an entire screen at a time. The ed program, in UNIX, is a line editor.

link
(a) The highlighted text or images used on the World Wide Web that take you from one page to the next page when you double-clicking on them.
(b) An additional name for a file in UNIX. When you create a file, you create its contents, which are stored on the disk somewhere, and you give it a name, which is stored in a directory. There is a connection between the filename and its contents. You can create additional filenames and connect them to the same contents by using the ln command.

local mount
To logically connect several disk drives on the same machines so that they appear as one file system.

log in
To identify yourself to the UNIX system and provide your password so that UNIX believes that it's really you and lets you use the computer. You have a login ID, or user ID, or user name, that is the name by which UNIX knows you. When you finish working you log out.

.login
On UNIX machines, a hidden file containing a shell script. If you use the C Shell, this script runs automatically every time you log in.

login directory
See home directory.

lynx
A text based browser for the World Wide Web available on UNIX machines.


M



M, MB, or Megabyte
A measure of memory and disk size that is 1,048,576 bytes, or 1K times 1K, or 2 multiplied by itself 20 times.

mailbox
The file in which the electronic mail system puts your incoming mail.

mail reflector
A special mail address; electronic mail sent to this address is automatically forwarded to a set of other addresses. typically they are used to implement a mail discussion group.

man page
On UNIX machines, a short file of information about a UNIX command. The man command displays manual pages about all UNIX commands and a few other topics, although they usually are written in a hopelessly technoid style.

memory
The storage area where the computer puts information it is working on right now. This is useful for only short-term storage (like until tomorrow). For long-term storage, computers put information on disks. Also known as main memory or RAM.

menu
A list of choices, usually commands, from which you can choose.

MILNET
One of the DDN networks that make up the Internet; devoted to non-classified military (U.S.) communications. it was built using the same technology as ARPAnet, and remained in production when the ARPAnet was decommissioned.

modem
A piece of equipment that connects a computer to a data transmission line (typically a telephone line of some sort). Normal people use modems that transfer data at speeds ranging from 1200 bits per second(bps) to 19.2 Kps. There are also modems providing higher speeds and supporting other media. These are used for special purposes - for example, to connect a large local network to its network provider over a leased line.

monitor
See screen.

Motif
A GUI based on the X Window System and distributed by the Open Software Foundation.

mounting directories
Logically attaching the root directory (UNIX) of one file system to some other directory so that you can treat all the files in the file systems as though they were subdirectories. Mounts can be local (on the same machine) or remote (on a different machine).

mouse
A pointing device that lets you move the cursor on-screen. Mice are used in conjunction with GUIs and the World Wide Web.

N



netiquette
Rules of polite behavior on the Internet, particularly in email and news.

network
A bunch of computers connected by some combination of cables, phone lines, satellites, or whatever. A network enables computers (and their users) to share information and peripherals. The especially good for sharing printers (so that you can all share one good but expensive laser printer) and or passing around email.

NeXTstep
An extremely cool GUI that runs on NeXt machines.

NFS
(a) The Network File System; a set of protocols that allows you to use files on other network machines as if they were local. Rather than using FTP to transfer files to your local network, you would be able to read, write and edit the file using the same commands as if it were local while it remains of the remote machine. NFS was originally developed by Sun Microsystems, Inc., and is currently in widespread use.
(b) Network File System. A network system that lets you treat files the on another computer in more or less the same way you treat files on your own computer.

NIC
(a) Network Information Center; any organization that's responsible for supplying information about any network.
(b) The DDN's NIC, which plays an important role in overall Internet coordination.

NIS
Network Information System. A database containing the user names, machine names and directory names NFS use to give consistent names on all machines on a network.

NOC
Network Operations Center; a group which is responsible for the day-to-day care and feeding of a network. Each service provider usually has a separate NOC, so you need to know which one to call when you have problems.

Novell NetWare
A network system that works on PCS, Macs, and UNIX machines.

NREN
The National research and Education Network; a U.S. effort to combine networks operated by different federal agencies into a single high-speed network. While this transition will be if significant technical and historical importance, it should have no effect on the typical Internet user.

NSFNET
The National Science Foundation Network; the NSFNET is not the Internet. It's just one of the networks that make up the Internet.


O



octet
Internet standards-monger's lingo for a set of 8-bits, i.e., a byte.

online service
A computer you can call, log in to, and use, usually for a fee per hour. Some services provide a specific set of information: Lexis, for example, provides legal information, Nexis provides news. Others provide general information: CompuServe, Delphi, and Prodigy, for example, provide a wide range of information, including weather, airline flights, and support for many software programs. Others, like MCI Mail, provide simply electronic mail (email).

OPEN LOOK
A GUI based on the X Windows System and developed by USL.

operating system
A special program that controls the way the computer, keyboard, screen and disks work together. UNIX is an operating system, as is DOS.

option
Known also as a flag or a switch. An option is something that tells UNIX how to do a command. You type an option on the command line after the name of the command, separated from the command by a space. All options begin with a dash(-). The ls command used with the -l option, for example, produces a file listing with more information about each file.

OSF (Open Software Foundation)
A source of UNIX-like and related software. Its best known products are OSF/1 and Motif.

OSF/1
A version of UNIX from the Open Software Foundation.

OSI
Open Systems Interconnect; another set of network protocols. See ISO.


P



packet
A bundle of data. On the Internet, data is broken up into small chunks, called packets; each packet traverses the network independently. Packet sizes can vary from roughly 40 to 32000 bytes, depending on network hardware and media, but packets are normally less than 1500 bytes long.

parent directory
In UNIX, the directory that contains the current working directory. That is, the current working directory is a subdirectory of the parent directory.

password
A secret series of characters known only to you. You type your password when you log in.

pathname
Instructions for how to get to a file. An absolute pathname tells you how to find a file beginning at the root directory and working down the directory tree. A relative pathname tells you how to find the file starting where you are now.

PC
A personal computer, usually one running DOS.

PCL
Printer Control Language; understood by a variety of printers made by Hewlett Packard.

peripheral
Something that lets the computer communicate with the outside world - mainly with you. The keyboard, screen, mouse, printer, and modem are all peripherals.

permissions
On UNIX machines, whoever has permission to look at, change, and execute stuff in a file or directory.

pipe
The | character in UNIX, used to redirect the output of one command so that it becomes the input of another command.

policy independence
A characteristic of the X Window System in which windows can look and act any way the software developers want. This idea is the converse of the idea that, if all the windows on your screen look and act in a similar way, they will be easier for you to use.

port
(a> A number that identifies a particular Internet application. When your computer sends a packet to another computer, that packet contains information about what protocol it's using (e.g., TCP or UDP), and what application it's trying to communicate with. The port number identifies the application.
(b) One of a computer's physical input/output channels (i.e., a plug on the back.).
Unfortunately, these two meanings are completely unrelated. The first is more common when you're talking about the Internet (as in telnet to port 1000); the second is more common when you're talking about hardware (connect your modem to the serial port on the back of your computer).

portable software
Software (programs) that can be run on a number of different kinds of computers. UNIX is portable because it runs on an amazing number of different types of computers.

POSIX
The IEEE portable operating system interface. POSIX defines a family of definitions of how parts of computer systems work with each other and, incidentally, with users. POSIX is intended to look just like UNIX but to be independent of any specific vendor. There are about a dozen members of the POSIX family; the one most people are concerned with is 1003.2 (known as "dot two") and the related user portability extension(UPE). Together, they define the way the commands and shells work. A system that complies with 1003.2 and UPE looks enough like UNIX to be familiar.

posting
An individual article sent to a USENET news group; or the act of sending an article to a USENET news group.

PostScript
A computer language spoken by printers and the programs that communicate with these printers, PostScript enables printers to print a wonderful array of characters in all kinds of sizes and shapes, as well as pictures. When a program wants to print something on a PostScript printer, rather than just send the characters to print, it has to send a PostScript program that tells the printer how to print the stuff.

PPP
Point to Point Protocol; a protocol that allows a computer to use the TCP/IP (Internet) protocols (and become a full-fledged Internet member) with a standard telephone line and a high-speed modem. PPP is a new standard which replaces SLIP. Although PPP is less common than SLIP, it is quickly increasing in popularity.

printer
A machine that makes marks on paper, preferably representing the letters or pictures you requested. There are many kinds of printers. The printer may be connected to your computer; if you are on a network, it may be connected to a computer elsewhere in your office. To find it, just listen for the sound of printing or follow people around for a while.

process
A running program.

.profile
A hidden file that contains shell commands. If you use the Bourne of Korn Shell, this file runs automatically every time you log in.

program
See software.

prompt
The character of characters displayed whenever UNIX (or some other program) is waiting for you to type something. The two common UNIX prompts are $ (if you use the Bourne or Korn Shell) or % (if you use the C Shell).

protocol
A protocol is just a definition for how computers will act when talking to each other. Protocol definitions range from how bits are placed on a ware to the format of an electronics mail message. Standard protocols allow computers from different manufacturers to communicate; the computers can use completely different software, providing that the programs running on both ends agree on what data means.

pushpin
A cute, little gizmo in the upper left corner of an OPEN LOOK window. If you push in the pushpin, it pins the window so that it stays open.


Q



queue
A waiting line, just as in real life. The most common queue is the print queue, in which the output of a print command waits in line to get printed.


R



RAM
Random-access memory. See memory.

read-only
A file can be read (copied, and so on) but not written (changed). UNIX has a system of permissions that enables the owner of the file, the owner's group, or all users to have or not have permission to read, write or execute the file.

real-time
Right now, as opposed to whenever the computer gets around to it.

redirection
To hijack the output of a command, which is usually on-screen, and put i somewhere else (this process is called out-put redirection). Alternatively, you can use information from somewhere else as the input of a command (called input redirection) rather than take the input from the keyboard. To redirect the output of a command to a file, use the > character. To redirect the input of a command from a file, use the < character. To redirect the output of one command to become the input to another command, use the pipe (|) character.

remote login
Logging in to another computer from your own computer. This process requires that your computer be on a network or have a phone-modem connection to one.

remote mount
Using NFS to connect directories from disk drives on other machines so that they appear as part of your file system.

request ID
The ID number of a print job as it waits in the print queue for the printer daemon to get around to printing it. You need to know the request ID if you want to cancel printing when, for example, the output is horribly fouled up and wasting lots of paper.

RFC
Request for Comments; a set of papers in which the Internet's standards, proposed standards and general agreed-upon ideas are documented and published.
RFS
Remote File Sharing. Like NFS, a program that lets you treat files on another computer in more or less the same way as you treat files on your own computer.

RISC
Reduced Instruction Set Computer. A type of CPU chip. Different from CISC.

root
See superuser.

root directory
The main, top-level directory on a disk. All the files on the disk are in either the root directory or a subdirectory of the root directory (or a sub-directory, and so on).

rotating backups
Not using the same tapes or floppy disks every time you make a backup. By rotating among two, three, or more backup sets, you have a longer history and a more reliable system.

router
A system that transfers data between two networks that use the same protocols. The networks may differ in physical characteristics (e.g., a router may transfer data between an Ethernet and a leased telephone line.)

RTFM
Common abbreviation in mail and news; meaning read the f#@#!#@ manual.


S



screen
The TV-type thing that shows you what's going on in your computer. Also called a monitor, CRT, and VDU. Some screens can display many colors; others an do only one, usually green. Some screens can display pictures (graphics); others can do only characters.

screen editor
A text-editor that deals with text an entire screen at a time. The vi and emacs programs are screen editors.

script
See shell script.

SCSI
Small Computer Systems Interface. A way to connect a disk drive to a computer. A SCSI disk (pronounced "scuzzy") can connect to any SCSI-compatible connector, used by many workstations, PCs, and Macs.

search path
A list of directories in which UNIX looks for programs.

server
See X server.

server
(a) Software that allows a computer to offer a service to another computer. Other computers contact the server program by means of matching client software.
(b) The computer on which the serer software runs.

service provider
An organization that provides connections to a part of the Internet. If you want to connect your company's network, or even your personal computer, to the Internet, you have to talk to a service provider.

shar message
An email message that contains a shell script, which, when you run it, re-creates one or more files. This is a clever way to send files through email.

shell
On a UNIX system, software that accepts and processes command lines from your terminal. UNIX has multiple shells available (e.g., C shell, Bourne shell, Korn shell), each with slightly different command formats and facilities.

shell script
A file that contains a list of UNIX shell commands. You can run a shell script, thereby telling UNIX to execute every command in the list.

signature
A file, typically five lines long or so, that people often insert at the end of electronic mail messages or USENET news articles. A signature contains, minimally, a name and an email address. Signatures usually often contain postal addresses, and often contains silly quotes, pictures, and other things. Some are very elaborate, though signatures more than 5-6 lines are questionable in taste.

slash
The / character UNIX uses in pathnames. A / by itself, or at the beginning of a pathname, means the root directory of the file system. Slashes are used also between one directory name and the next, and between the directory name and the filename in long paths.

SLIP
Serial Line IP; a protocol that allows a computer to use the Internet protocols (and become a full-fledged Internet member) with a standard telephone line and a high-speed modem. SLIP is being superseded by PPP, but is still in common use.

smiley
Smiling faces used in mail and news to indicate humor and irony. The most common smiley is :-). You'll also see :-(, meaning disappointment, and lots of other variations. You'll pick up their connotations with time.

snail-mail
A mail system in which you print the message you want to send to another person, address a paper envelope of the correct size to fit the paper, insert the paper in the envelope, close the envelope, find a postage stamp, and place the entire thing in a U.S. mail box. Many UNIX and Internet users find email simpler, faster, and more convenient.

soft link
A link that contains the name of another file, which may be on another file system. A soft link makes it look as though the file that might be on another file system is in a directory on your own file system. Also called a symbolic link.

software
A set of instructions (also called programs) that tell a computer to do something. In contrast to hardware, which includes the physical components of your computer, software is composed of information on a disk.

Solaris
A version of UNIX, based initially on BSD UNIX and later on System V Release 4, distributed by Sun for use on Sun workstations and 486 PCs.

SRI
A California-based research institute that runs the Network Information Systems Center (NISC). The SRI has played an important role in coordinating the Internet.

subdirectory
See directory.

superuser The user name (known as root) with which you can do all sorts of dangerous things to the system, including creating new user names and installing new hardware and software. With luck, you don't know the password for the superuser. If you do, use it carefully. The system administrator really should be the only person who logs in as the superuser.

SVR4
Release 4 (the latest major version) of UNIX System V. Contains more features than any six people would ever want to use. The latest release of SRV is SVR4.2 which is even more feature-packed than the original version of SVR4.

switch
See option.

switched access
A network connection that can be created and destroyed as needed. Dialup connections are the simplest form of switched connections. SLIP or PPP also are commonly run over switched connections.

system administrator
The person whose job it is to keep the computer, and possibly the network, running.

System V
A version of UNIX developed and distributed by AT&T and later by UNIX System Labs, which is now part of Novell.


T



tape
A computer tape stores vast amounts of information but is not convenient to use. Tapes are primarily used for making backup copies of information, for which they are terrific. With luck, your system administrator backs up your files regularly.

TCP
The Transmission Control Protocol. One of the protocols on which the Internet is based. For the technoids, TCP is a connection-oriented reliable protocol.

telnet
(a) A terminal emulation protocol that allows you to log in to other computer systems on the Internet from your own computer.
(b) An application program that allows you to log in to another computer systems using the telnet protocol.

terminal
A screen and keyboard connected to a computer somewhere else. The terminal doesn't run UNIX and all those neat programs itself, it just lets you use the computer that does.

terminal emulator
A program that enables a big, powerful computer to act like a dumb, cheap terminal. Commonly, a PC can run a terminal emulator so that you can use another computer running UNIX. UNIX includes a simple terminal emulator called cu.

terminal output stop mode
A terminal setting in which a background job stops if it tries to send anything to your screen.

text editor
A program that lets you create files of text and edit (or change) them. The most common UNIX text editors are ed, vi, emacs, and pico.

text file
A file that contains lines of text. All the stuff in a text file must be ASCII characters - no bizarre control code, data, programs, or the like. You can use the cat command to look at a text file on-screen. If it looks like it was written by Martians when you use the cat command to view it, it's not a text file.

text formatter
A program that reads text files and creates nice-looking formatted output. The most common UNIX text formatters are troff, nroff, and TeX.

time out
A time out is what happens when two computers are talking and one computer - for any reason - fails to respond. The other computer will keep on trying for a certain amount of time, but will eventually give up.

tn3270
A special version of the telnet program that interacts properly with IBM mainframes.

Token Ring
A technology for creating a local area network that may be then connected to the Internet. Token Ring networks often use the TCP/IP protocols. See also, in relations, Ethernet.

trackball
A pointing device, equivalent to a mouse lying on its back, that lets you move the cursor on the screen.


U



UDP
The User Datagram Protocol. Another of the protocols on which the Internet is based. For the technoids, UDP is a connectionless unreliable protocol. If you're not a technoid, don't let the word unreliable worry you.

UNIX
(a) A popular operating system that was very important in the development of the Internet. Contrary to rumor, though, you do NOT have to use UNIX to use the Internet. There are various flavors of UNIX. Two common ones are BSD and System V.
(b) An operating system written by a couple of people at Bell Laboratories in 1972. They also wrote the C programming language. Since then, several variants of UNIX have appeared, including BSD UNIX, System V UNIX, and Xenix.

UNIX International (UI)
A consortium of computer vendors that supports System V and gives guidance to USL.

UNIX System Laboratories (USL)
The organization that develops and maintains UNIX System V. Originally owned primarily by AT&T, it is now part of Novell.

Usenet
(a) The USENET is an informal, rather anarchic, group of systems that exchange news News is essentially similar to bulletin boards on other networks. USENET actually predates the Internet, but these days, the Internet is used to transfer much of the USENET's traffic.
(b) A very large, very informal, very disorganized network through which many megabytes of news, rumor, and gossip are distributed every day.

user name
The name by which UNIX knows you. You enter this name when you log in, Also known as user ID or login ID.

utility
A small, useful program. UNIX comes with some utilities like diff and sort.

UUCP
(a) UNIX-to-UNIX copy, a facility for copying files between UNIX systems, on which mail and USENET news services were built. While UUCP is still useful, the Internet provides a better way to so the same job.
(b) The UNIX-to-UNIX copy program. One of the ways that mail, usenet news, and random files can be sent between computers.

uuencoded file
An electronic-mail message format that contains a binary file disguised as text. When you run the message through uudecode, the binary file is reconstituted. This is a clever way to send binary files through email.


V



virtual memory
A sneaky trick by which UNIX, or Macs, or Windows machines pretend to have more memory that they really do. When you are not looking, they copy information from memory to the disk to free up space in memory. When you need the information on disk, they copy it from the disk back into memory. Virtual memory is generally invisible, except when a program uses it too enthusiastically; then the computer spends all its time copying stuff back and forth to disk and no time doing useful work, a condition often called thrashing.

W



WAIS
Wide-area information servers; a very powerful systems for looking up information in databases (or libraries) across the Internet.

White Pages
Lists of Internet users that are accessible through the Internet. There are several different kinds of white-pages servers and services.

wildcard
A special character that acts like a joker when it is used in filenames or pathnames. UNIX shells have two: * and ?.

WIMP
Translation: Windows, icons, and mouse pointing. See GUI.

window
A rectangular area of screen in which a program displays something. If you use a GUI, you can have several windows on screen at a time, each displaying a different program.

window manager
The program (lie OPEN LOOK or Motif) that gives the screen the overall look of a GUI.

wizard
A person who knows more about UNIX than the average bear.

word processor
A program that lets you create documents - files that contain text, pictures, and formatting codes. UNIX word processors include WordPerfect and Microsoft Word.

working directory
The directory you are working in. The pwd command tells you your working directory.

workstation
A computer with a big screen, a keyboard, and a mouse. If it runs UNIX, it's called a workstation if it runs DOS, it's called a PC. And, if it runs Macintosh System, it's called a Mac.

World-Wide Web
A hypertext-based system for finding and accessing Internet resources.

WWW
A common abbreviation used in mail and news, meaning World Wide Web.

X



X server
A program that draws the pictures and displays the text on-screen if you use the X Windows System or a GUI based on X.

X terminal
A terminal that can act as an X server so that you can use the X Windows System, Motif, or OPEN LOOK. It has a little computer in it to do the X-specific stuff.

X Windows Systems (X)
A GUI designed at MIT. Two other major HUIs, Motif and OPEN LOOK, are based on X.

XENIX
A version of UNIX developed by Microsoft and now maintained and distributed by SCO (Santa Cruz Organization).


Y



Yellow Pages
See NIS.


Z