1337 geek paraphanelia : t-shirts, mugs, mouspads, etc.

Glossary of Terms regarding Linux, Networking and Computing in General and pertinent to the CWRU Computing Community

First edition: February 22nd, 2000 (Last Updated September 13, 2000)
Maintainer / Author: Paul "Froggy" Schneider (froggy@eecs.cwru.edu)

Michael Perlman (mdp2@po.cwru.edu)
Jose Nazario (jose@biocserver.bioc.cwru.edu)
Braden McGrath (bwm3@po.cwru.edu)
Amitai Schlair (ays@po.cwru.edu
Steven Izen (shi@po.cwru.edu)
Paul Jarc (prj@po.cwru.edu)
Chet Ramey (chet@nike.ins.cwru.edu)
Ian Charnas (icc@po.cwru.edu)
Brian Glenn (glenn@ct.picker.com)
Keith Higgs (dkh2@po.cwru.edu)

&: See amp it off.

*-Fu: Cunning skill, dexterity and deftness with some particular art. (i.e. web-fu, perl-fu or script-fu for great skill in all things web, perl or scripting, respectively).

amp it off: A reference to using the & to run a program in the background, allowing for the user to continue doing other work in the foreground.

Administrator: See root.

ADSL: Acronym for "Asynchronous Digital Subscriber Line".

AFAIK: Acronym for "As Far As I Know".

AFK: Acronym for "Away From Keyboard".

Apache: The name of an extremely popular and stable web server. It is included with many distributions of Linux and BSD and is also available for Windows NT and other Unix variants.

ATM: Acronym for "Asynchronous Transfer Mode". A system for moving data on a network. This is done on the link-layer of the 7 layer OSI model. Contrast with Ethernet.

AUI: Acronym for "Attachment Unit Interface". A type of ethernet interface that has 15 pins in a trapezoidal shape (similar in shape to a serial or parallel connector, but most like a Joystick adapter. Interstingly enough, mixing the two accidentally usually leads to woe.) Also referred to as 10Base-5.

authentication: The procedure of verifying whether a remote user and/or computer system is really who he/she/it is. Kerberos is an example of an authentication algorithm. Not to be confused with authorization.

authorization: The procedure of determining which facilities a user has permission to use. Not to be confused with authentication. Rather, authorization occurs after authentication, and relies on its accuracy.

background: The metaphorical term for the location of an amped off process. It basically means that the process does not have control of the shell it was run under.

B1FF: Writing in the style of elite hackers (whom are neither elite nor hackers, but that's beside the point), or in the b1ff "31337 HAX0RZ." It usually involved mispellings and the replacement of letters with numbers which have similar visual effects, often in upper case. No one should be or would want to be considered a B1FF.

blowfish: An encryption algorithm that scales easily to faster processors. To increase the level of compute power required to encrypt, simply increase the number of "rounds".

BOFH: Pronounced phonetically as "bawf". Ancronym for "Bastard Operator From Hell". A term of endearment and/or derision as applied to a system administrator that generally has contempt for stupid users and/or lusers. Usually applied to someone for comedic purposes, but often hinting at mild "holier than thou" attitude exhibited by some sysadmins

BRB: Acronym for "Be Right Back".


BSD: Berkeley Software Distribution. The original or derivative works of the Berkeley UNIX project which added functionality to AT&T's System V UNIX. Addres such things as IP networking and virtual memory. Terminated in 1994 with the last release as 4.4BSD. Because each *BSD is distributed and developed as a complete system (as opposed to most Linuxes), the kernel, libraries, and utilities are well integrated, and the result is a very polished system. Many of the features standard in modern Unix were research projects originally developed on BSD Unix. Some Unix users, especially old-school cognoscenti and anyone who learned Unix on *BSD, consider the free BSD systems technically superior to Linux in many respects. See also *BSD.

*BSD: Free derivatives of the BSD project, including NetBSD, OpenBSD, and FreeBSD. They are in current development and run on a wide variety of hardware platforms.

BSD License: This license was made popular by much of the software coming out of the University of California, Berkeley. Similar to the GPL in some respects, it, too, allows for the free distribution of both programs and source code. A copy of the license can be found at http://www.opensource.org/licenses/bsd-license.html Depending on who you ask, the BSD License can be considered either more free (because of the very few restrictions) or less free (because anyone can hoard his local source code changes) than the GPL.

C: (1) A programming language. (2) The most popular programming language. (3) The programming language that most of Linux and BSD was written in. (4) The programming language that was written for the purpose of making UNIX portable (see portable).

CGI script: CGI is an acronym for "Common Gateway Interface". CGI scripts allow web page designers to have the viewer's of their page use it interactively. For example, online retailers use a form of CGI scripting that allows people to choose items they want and then generate a web page dynamically describing the items. A lot of CGI scripting is done in Perl, PHP and C.

compiler: A program that will interpret text source code and turn it into an executable program.

copyleft: (1) A place to get geeky t-shirts and the like. http://www.copyleft.net/.

cracker: An individual who enjoys breaking into, changing and disrupting the operations of a computer system that they do not own or have any right accessing. Most crackers are script kiddies, but the term can also be used to refer to the truly nefarious individuals who wish to cause serious damage to others' computer systems. Not to be confused with hacker

cron: cron is a Unix utility that allows users to schedule programs to run at a specified time, time interval or date. Useful for logging, checking network links, etc.

crypto: Short for "cryptography". Often used when referring to both encryption and decryption.

daemon: See service. decryption: The act of taking encrypted data and turning into a readable form.

/dev/null: Can be thought of as a "black hole" for computer data. /dev/null is often used to Unix systems as the destination for program output that the user either doesn't want to see.

DHCP: Acronym for "Dynamic Host Configuration Protocol". DHCP allows a computer to automatically configure it's network settings (including IP Address, DNS, gateway and netmask.

distribution: A complete Linux operating system package, including the kernel, commonly used programs, configuration scripts and applications. Some popular distributions include Debian, Red Hat, SuSE, Slackware and Yellowdog.

DNS: Short form of the phrase "Domain Name Server". DNS servers are used to convert hostnames such as www.cwru.edu into an IP Address. The acronym also expands to Domain Name Service and Domain Name System, depending on context.

DSL: Acronym for "Digital Subscriber Line".

E: See Enlightenment.

Elan: Emulated LAN. (Definition 1) Emulated Local Area Network. Refers to a configuration of ATM in which devices appear to be on a "regular" LAN so that they can communicate via several common networking protocols (IPX/SPX, AppleTalk, TCP/IP). As opposed to CLIP (Classical IP) and "native" ATM networking. (Alternate defiition 1) In ATM networks, emulating an ethernet LAN by splitting Ethernet packets into ATM Cells, sending them to their destination, and re-packaging them into ethernet packets. Multiple ELANs can exist on the same ATM network

elite: Also known as "31337" (if you don't get the similarity, try thinking of the numbers as letters), Also know as "l33+" (with the + sign representing the letter "t"). To be greatly skilled in the hacker arts. Usually claimed by those that are not.

emacs: Pronounced "ee mackss". A very feature rich and extensive text editor with many features available for people that do programming and shell scripting.

encryption: The act of scrambling data in such a way that it will be unreadable by anyone except the intended receiver. This is possible because a "key" is used to add uniqueness to the operation. Compare with decryption. Sometimes referred to by it's shortened form, crypto.

Enlightenment: AKA E. (1) A state of being one comes into after realizing *NIX is cool. (2) A very pretty window manager that makes using X Windows "enlightening" because of its use of pretty graphics and effects. Current versions have the ability to overlay with GNOME and/or KDE, thus providing expanded "skin-ability" and visual customization to the windowing environment.

/etc/passwd: The master user database for a Unix system. Also, can hold encrypted forms of the users' passwords.

file manager: An application that helps users manage their user files and data on a computer system.

firewall: A device or set of devices and protocols that separates network traffic, usually onthe basis of a set of rules to allow only certain traffic through. See packet filters.

FOT: Fiber Optic Transceiver.

free: Many computer users add connotations to this word that many in the mainstream do not. To be "free", an application is (usually) released under a license (see GPL and/or BSD License) that not only allows (and in most cases requires) that the software be available free of charge, but that the source code must be be freely available as well, allowing users to customize the program to fit their needs. However, this does not preclude companies from selling a version of the product with a support package in an effort to capitalize on the work and development put into it. Red Hat is a good example of this.

fsck: Pronounced as "fisk". (1) A program that does integrity checks on Unix file systems. These checks ensure the reliability and usability of Unix system volumes. (2) Often used as an alternative to a similar-in-sound "dirty" four-letter word.

FTP: Acronym for "File Transfer Protocol". FTP allows users to transfer files to and from an FTP server.

FUD: Acronym for "Fear, Uncertainty and Doubt". A technique used by some software companies against competing products to attempt to convince customers that there is some fatal problem or flaw inherent in the competing system, often with questionable legitimacy.

full-duplex: AKA 'FDX' The process of transmitting and recieving information at the same time. usually refers to network devices. most switches can run in full-duplex, providing double the aggregate throughput of a normal Ethernet device. ATM devices run in full-duplex mode by design.

gateway: The router that provides access between different networks.

gcc: Pronounced as "gee see see". (1) The GNU Compiler Collection. (2) Primarily, a C compiler available on almost every Unix operating system that allows programmers (and non-programmers alike) to compile source code into a fully operational application.

Gnome: The GNU version of KDE, basically. A file manager and window manager rolled into one.

GNU: Pronounced "Gah new", like the animal. (1) A recursive acronym for, "GNU's Not Unix". (2) Often an acronym used to refer to the GNU Project (http://www.gnu.org). From the GNU Project web page: "The GNU Project was launched in 1984 to develop a complete Unix-like operating system which is free software: the GNU system. Variants of the GNU operating system, which use the kernel Linux, are now widely used; though these systems are often referred to as "Linux", they are more accurately called GNU/Linux systems." The last phrase tends to be a source of endless debate among many.

GPL: Acronym for "General Public License". Usually seen as GNU GPL. Basically, the license allows for authors to release their work for free, source code and all, while still holding ownership of the code. You can read the full license yourself by going to http://www.gnu.org/copyleft/gpl.html

grok: The act of gaining understanding, usually by hacking away at something. Originated in Robert A. Heinlein's book, Stranger in a Strange Land.

guru: One who has great knowledge, far beyond that of mere mortals. Bestowed only on those truly worthy.

hacker: (1) An individual who enjoys programming, seeking out and finding security vulnerabilities in systems in an attempt to make them more secure and/or likes fooling around with new technologies. (2) A term often misused by the media to refer to what is commonly known in the hacker community as a cracker. Unfortunately, after over a decade of misuse and repeated derision by the hacker community, the term is still in use to refer to acts (often illegal) performed by crackers

hacking: The art, study and hobby of playing with, engineering, designing and fixing computing systems and software. Can also be used when talking about other, non-computer related subjects. For example, "I've been hacking away at this chili recipe all week. Now it tastes great!"

hostname: A name given to a particular machine or host.

hub: A device that repeats frames to all devices connected. See switch.

HUP: Acronym for "Hang UP". By sending a process a HUP signal, the user can often tell it that it should re read it's configuration file. This is only a convention, however, and not an absolute. The shell, for example, will clean up and terminate on SIGHUP.

IANAL: Acronym for "I Am Not A Lawyer". Often used to preface an opinion that could accidentally be interpretted as legal advice, especially in discussions involving either the GPL or BSD license.

inetd: A "super server" that has the ability to spawn any number of other servers and services upon an outside request. This is important because it allows one computer to run many services and to have those services loaded into memory only when they are used.

IP Address: Contraction of the phrase, "Internet Protocol Address". This is the absolute address by which a machine can be referenced and accessed. It can be thought of as a parallel to a regular post office mailing address. Each host has a unique address (i.e., no two computers may have the same IP address).

IRC: Acronym for "Internet Relay Chat". IRC is a popular and efficient way to talk to many people at the same time in a party-line style atmosphere. IRC servers usually has many channels (created by users) of various topics for discussion. IRC users and the IRC lifestyle often can take a life of its own. Much of the language, lingo and terminology used on IRC originates from the days when CB radio was popular.

ISDN: Acronym for "Integrated Services Digital Network". The combination of data and voice over one line. Popular due to its high speed compared to modems (Typically either 64 or 128 kbps, generally 2 to 5 times faster than an average modem and generally more stable.)

KDE: K Desktop Environment. A window manager and file manager rolled into one, a la GNOME.

Kerberos: A well designed and time-tested authentication system. It relies on the absolute security of the Kerberos server.

kernel: The central core of every operating system. The kernel allows the user programs to interact with the computer peripherals and generally does a lot of the housekeeping necessary to keep the computer running in tip-top shape. The term Linux by definition refers to the kernal, whereas the term distribution refers to the packaged applications and programs that interact with the Linux kernel.

kill: A program that allows users to send signals to processes. Originally a one-trick pony that terminated a process, the name has long since become a misnomer. Often used to allow a user to force programs to stop running. There are many ways to kill a program, from asking the program nicely to quitting (see HUP) to stopping the program at all possibly costs without regards to potential consequences.

LANE: Acronym for "LAN Emulation". A technique used with ATM to simulate a network based on Ethernet.


lilo: Acronym for "LInux LOader". Lilo allows a user to boot more than one operating system on their computer. Also, lilo allows users to boot more than one kernel, which can come in handy for debugging purposes.

Linux: A Unix-like operating system released under the GPL by Linus Torvalds in the early 1990s. Today Linux has grown from a student project into a growing industry. The main selling point (for business folk and geeks alike) is that the kernel (and most if not all of the applications programs) are free.

LOL: Acronym for "Laughing Out Loud".

LUG: Acronym for "Linux Users Group".

lusers: A play on words for the term "users". The term has significant historical background that the reader is encouraged to explore as an exercise.

milo:Acronym for "MIni LOader". Similar to lilo in purpose and functionality. Milo is used on Alpha processor based systems to load Alpha versions of Linux, *BSD and other operating systems.

MUD: Acronym for "Multi-User Dimension". Also "Multi-User Dungeon". Muds are basically large multiplayer text games that tend to be extremely addictive.

net mask: The number that identifies which bits of a network address are defined by the network and which are specific to the subnet and host.

NIC: Almost always pronounced "nick". Network interface card. Usually an additional piece of hardware, like an ATM adpater or an Ethernet card, but sometimes they're built in to the motherboard.

partition: A portion of a disk drive that is reserved exclusively to hold data (whether it be programs, swap, user data, etc.). Each drive must be partitioned in order to be used by the operating systems. Usually, partition structures cannot be used by other operating systems (i.e. Windows will have a hard time understanding and Linux file system). There are exceptions, of course. This restriction is entirely operating system dependent.

Perl: A scripting language originally designed for Unix that can now be found on many other platforms, including Windows. Perl is considered by many sysadmins to be an excellent choice for automating many trivial and time consuming (if done by hand) tasks. Compare to shell scripting. Perl is generally considered an acronym for "Practical Extraction and Report Language" and was designed by Larry Wall.

PHP: Recursive acronym for "PHP Hypertext Preprocessor". A scripting language used in HTML pages. Processing is done by the server, outputting HTML to the client. Popular due to its flexibility and interopobility with a wide variety of data back ends.

portable: Describes code written in a manner so as to be easily made to run on another system or architecture. Before UNIX, operating systems were written in assembly language; UNIX became the first portable operating system when it was reimplemented in C, a relatively high-level language. NetBSD takes this heritage to the extreme by compiling for dozens of architectures from a single source tree.

POTS: Pronounced as "pots". Acronym for Plain Old Telephone Service. What we all live and suffer with.

ppp: Point to Point Protocol, usually referring to the protocol used by dial up connections over a modem line. PPP is preferred over SLIP due to robust compression and error handling.

process: A term used to refer to any program that is currently running.

pr0n: Pronounced, "prahn". A butchering of the term "porn" which is, obviously, short for pornography. Often used by the semi-mythical B1FF.

Python: A robust object oriented scripting language. Popular for its flexibility and ease of use.

QoS: Acronym for "Quality of Service".

respef: Akin to respect, but much deeper. Coined by Paul Schneider over a lunch converstaion with some compadres in the Summer of 1999 at the Biomedical Research Building (BRB) at Case Western Reserve University. At the time, he was being ragged on by said group and blurted out in front of everyone at the table something akin to, "Stop it. Y'know, I just don't get any respef around here." To which an individual named merlin responded, "How do you expect to get respect if you keep talking like that!" From there on out it became an increasingly popular "in joke" at CWRU and grew over time to have attached to it deep feelings of respect and honor (curiously contrary to it's original usage).

r00t: See root.

root: (1) noun: The one account on a computer system that has absolute and supreme control over it. Those individuals with a root account are often referred to as system administrators. Also called the system superuser. On non-Unix systems, (i.e., Windows NT), the account is often called (blandly) Administrator. (2) verb: To obtain unauthorized root access.

router: A device that reforms routing between two or more networks. It uses store and forward methodologies for handling packets and uses routing tables to decide on where to send a packet on the basis of its final destination.

routing: The process of forwarding packets to the next host or endpoint during their travels from one network node to another. this is usually done by a device called a router.

RTFM: Acronym for "Read The F*** Manual" where F can be, for example, "Fucking", "Fine", etc.

Samba: A free implementation of the Server Message Block (SMB) protocol used by Windows computers.

script kiddy: A person, generally a novice computer user that learned a neat trick and suddenly gained a rather large ego, that uses programs and scripts written by others to attempt to get access (usually root) to other peoples' computers. Compare with cracker. (OpenBSD PLUG: OpenBSD, a relatively secure Unix, sells t-shirts in which a hardened blowfish swims happily in his bowl, unconcerned about the "script kitty" watching him.)

SDSL: Acronym for "Synchronous Digital Subscriber Line". With SDSL, both the upstream and downstream data transfer rates are the same. Contrast ADSL.

service: A program, almost always running in the background, that performs some function that "serves" out data to other users. Examples include web servers, ftp servers, etc. On Unix, usually called a daemon.

shell scripting: A mini "programming language" that Unix users can use to automate tasks that are either tedious, repetitive or difficult to do by hand. Unix offers many different shells and each shell's language is different from the others. Often compared to DOS and Windows style "batch scripts". While this is a valid comparison, shell scripts tend to be exceedingly more flexible and powerful.

slashdot: Almost always a reference to the Slashdot (http://slashdot.org) on-line news source. Widely read by nerds and straights alike, it is quite likely that you can start a good converstaion by saying, "I just read on Slashdot today..."

SLIP: Acronym for "Serial Line IP Protocol". Used to connect modems to computers in order io establish an IP presence on a network. Not widely used anymore in favor of PPP.

sniffer: A program or host that is actively examining all traffic it can see, including traffic that is not destined for it. Use by crackers to gleam passwords from the network and for system administrators for debugging network operations.

source: A text file containing all of the programming commands that, when compiled, can be executed on the computer.

superuser: See root.

swap: A partition on a Unix system that the operating system can use to temporarily store data for the purposes of increasing the amount of virtual memory in the system.

switch: A device that repeats frames only to the destination host. This is usually done by the switch creating an internal table of all hardware addresses know to it and on what ports.

switched Ethernet: Switched Ethernet requires a device called a switch to forward Ethernet frames from one computer to another. A 5 port switch, given incoming data on one port, will look up the MAC address of the destination computer in its internal memory and simply send the frames to the port that MAC address resides on. this differs from a hub - hubs simply repeat the data sent from one port out to all the others. Most switches can also operate in full-duplex mode. Theoretically, it is impossible to have collisions on a switch.

sysadmin: See System Administrator.

System Administrator: The person(s) with legitimate root accounts on a computer system. The person with the power. Some system administrators are either classified or classify themselves as BOFHs.

TCL: Pronounced "tickle". Refers to the Tool Command Language. A popular scripting language developed by John Ousterhout which runs on almost all popular computing platforms. Often paired with Tk.

thinkgeek: A place to get geeky t-shirts and the like. http://www.thinkgeek.com/

Tk: The Tool Kit, a GUI addition to Tcl. Can be paired with Perl and Python as well.

traffic: Generally refers to the amount of activity in a particular medium, especially in the world of networking. Hence, a high traffic network is generally congested and can, at times, be quite slow. Also used in reference to mailing lists with a similar analogy. High traffic lists tend to generate lots of messages, often more than the average mortal can ever hope to read in a day.

TTYL: Acronym for "Talk To You Later".

UNIX: Not an acronym, but a pun on MULTICS, another, more complex operating system from which some of the fundamental concepts of UNIX were derived.

UTP: Acronym for "Unshielded Twisted Pair". UTP is a common form of networking cable used almost everywhere but CWRU as a communications medium. UTP tends to be cheap and fairly reliable.

vi: Pronounced "Vee Eye". A commonly used (albeit cryptic for first time users) text editor.

virtual memory: A method devised to increase the apparant amount of physical memory a machine has. Thus, the total memory is the sum of the phyiscal memory (RAM) plus the size of the swap partition. Thus, programs are fooled into believing that they have access to much more physical RAM than is really available. Because disk access is orders of magnitude slower than RAM access, a system making significant use of its virtual memory is running suboptimally. Database and Web servers, for example, should never hit virtual memory.

volume: Another term for a disk partition.

warez: Illegally copied and distributed software.

WindowMaker: Another window manager. Much of it is based on that of the venerable NeXT Cube. AfterStep is its older cousin, but WindowMaker tends to have cooler features. A nice window manager for those searching for something nice to stare at yet don't want to devote the resources, time, or effort into mucking with E.

window manager: Often abbreviated as "WM". This is what gives your windows their appearance under the X Windowing System (X11). Typical WMs are: GNOME, KDE, Enlightenment, WindowMaker, ICEwm, FVWM, FVWM95, AfterStep, TWM, OLWM... the list goes on. The current favorites tend to be the first 3 or 4 of those. Some window managers are also file managers, in the case of GNOME and KDE.

X Windows: A hardware independent windowing system, usually refering to the base layer. Difficult to use without the aide of a window manager. Developed at MIT in the Athena Project.

xDSL: Used to refer to the many types of DSL lines available. See SDSL, ADSL and DSL

YMMV: Acronym for "Your Mileage Might Vary". Basically, "what works for me might not work for you... or might work better. Who knows?"

The Jargon File

© 2000 Paul "Froggy" Schneider (froggy@eecs.cwru.edu)