A B C D E G H I J K L M N P R S T U

ABEND or ABnormal END
Termination of software; crash; lossage. Derives from an error message on the IBM 360; used jokingly by hackers but seriously mainly by code grinders. Usually capitalized, but may appear as `abend'. Hackers will try to persuade you that ABEND is called `abend' because it is what system operators do to the machine late on Friday when they want to call it a day, and hence is from the German `Abend' = `Evening'.

Accumulator
Archaic term for a register. On-line use of it as a synonym for `register' is a fairly reliable indication that the user has been around for quite a while and/or that the architecture under discussion is quite old. The term in full is almost never used of microprocessor registers, for example, though symbolic names for arithmetic registers beginning in `A' derive from historical use of the term `accumulator' (and not, actually, from `arithmetic'). Confusingly, though, an `A' register name prefix may also stand for `address', as for example on the Motorola 680x0 family.

A register being used for arithmetic or logic (as opposed to addressing or a loop index), especially one being used to accumulate a sum or count of many items. This use is in context of a particular routine or stretch of code. ``The FOOBAZ routine uses A3 as an accumulator.''

One's in-basket (esp. among old-timers who might use sense 1). ``You want this reviewed? Sure, just put it in the accumulator.''

Access Control in networks
In the context of network security, access control is the ability to limit and control the access to host systems and applications via communications links. To achieve this control, each entity trying to gain access must first be identified, or authenticated, so that access rights can be tailored to the individual.

Ada
A Pascal-descended language that has been made mandatory for Department of Defense software projects by the Pentagon. Hackers are nearly unanimous in observing that, technically, it is precisely what one might expect given that kind of endorsement by fiat; designed by committee, crockish, difficult to use, and overall a disastrous, multi-billion-dollar boondoggle (one common description is ``The PL/I of the 1980s''). Hackers find Ada's exception-handling and inter-process communication features particularly hilarious. Ada Lovelace (the daughter of Lord Byron who became the world's first programmer while cooperating with Charles Babbage on the design of his mechanical computing engines in the mid-1800s) would almost certainly blanch at the use to which her name has latterly been put; the kindest thing that has been said about it is that there is probably a good small language screaming to get out from inside its vast, elephantine bulk.

Anisotropic Texture
Anisotropic textures contain patterns of more than one type. For example, an anisotropic texture for terrain modeling could contain a part of urban area on one side, with the rest of it covered by dense forest. See also, Isotropic texture.

Anonymous ftp
Anonymous ftp is a way to provide restricted file transfer access to a host for the Internet community at large. You typically use ftp to connect to a host and enter ``anonymous'' (possibly ``ftp'' or ``guest'') for the user name and your ``real'' user name for the password. Do not type your real password at any time, as it is common to log all anonymous transactions and your password would be visible on the remote system. When transferring files, make sure you have ``binary'' or ``image'' mode set for transferring binary (non-ASCII) files. This is true in the most common cases, such as compressed files or tar archives. In some rare cases, you might need ``tenex'' mode.

Bug
An error in the design or implementation of a program, that causes the program to do something unintended. The original bug was a moth stuck in a relay of ENIAC.

CPU or Processor
The brain of the computer system. CPU controls the operation of a computer system and performs all the thinking.

Cracker
On USENET, calling someone a ``cracker'' is an unambiguous statement that some person persistently gets his/her kicks from breaking from into other peoples' computer systems, for a variety of reasons. S/He may pose some weak justification for doing this, usually along the lines of ``because it's possible'', but most probably does it for the ``buzz'' of doing something which is illicit/illegal, and to gain status amongst a peer group.

Particularly antisocial crackers have a vandalistic streak, and delete filestores, crash machines, and trash running processes in pursuit of their ``kicks''. The term is also widely used to describe a person who breaks copy protection software in microcomputer applications software in order to keep or distribute free copies. (See also, Hacker)

[From FAQs of comp.security.misc]

Crossposting
The posting of the same message to multiple discussion lists or newsgroups. Useful when similar discussions happen in various fora. Irritating when posted to way too many groups just to get an answer from one of them.

DXE
Driver Execution Environment. Prepared by EFI to provide generic platform functions that EFI drivers may use. The drivers themselves provide specific platform capabilities and customizations.

Elephantine
Used of programs or systems that are both conspicuous hogs (owing perhaps to poor design founded on brute force and ignorance) and exceedingly hairy in source form. An elephantine program may be functional and even friendly, but (as in the old joke about being in bed with an elephant) it is tough to have around all the same (and, like a pachyderm, difficult to maintain). In extreme cases, hackers have been known to make trumpeting sounds or perform expressive proboscatory mime at the mention of the offending program. Usage: semi-humorous. Compare `has the elephant nature' and the somewhat more pejorative monstrosity. See also second-system effect and baroque.

Exception
An exception condition refers to unexpected events caused by a process, such as addressing illegal memory, executing privileged instructions, dividing by zero, and so on. Exceptions happen in the middle of the execution of an instruction, and the system attempts to restart the instruction after handling the exception. Interrupts are considered to happen between the execution of two instructions, and the system continues with the next instruction after servicing the interrupt.

FAQ Frequently Asked Questions
A document that is regularly posted to a newsgroup or a e-mail list to answer the questions that everyone who reads the group religiously is tired of answering. It is a good idea to read them before posting a question to the group.

Hacker
On USENET, calling someone a ``hacker'' is usually a statement that said person holds a great deal of knowledge and expertise in the field of computing, and is someone who is capable of exercising this expertise with great finesse.

In the ``real world'', various media people have taken the word ``hacker'' and coerced it into meaning the same as ``cracker'' -- this usage occasionally appears on USENET, with disastrous and confusing results.

[From FAQs of comp.security.misc]

Home page
The beginning point of a World Wide Web document. Since it is possible on the Web to start reading at any page in the world, it is also possible to begin reading where it makes no sense. The creator of a Web presentation puts a home page where he or she expects you to begin reading.

Interrupt
A hardware or software signal that indicates to the operating system the occurence of some event such as a keystroke. Interrupt is typically taken care of by an interrupt handler that services the event.

Intrusion
Any set of actions that attempty to compromise the integrity, confidentiality, or avaliability of a resource.

Isotropic Texture
Isotropic textures represent one and only one type of content type (for example, terrain type for terrain textures). Thus, an isotropic terrain texture contains only one of urban area, dense forest, or farmland textures. See also, Anisotropic textures.

Multiprogramming
A mode of operation that provides for the interleaved execution of two or more computer
programs by a single processor.

Process
A
program in execution; Execution of an executable file stored in the file system
Click here for detailed information.

Program

  1. A magic spell cast over a computer allowing it to turn one's input into error messages.
  2. An exercise in experimental epistemology.
  3. A form of art, ostensibly intended for the instruction of computers, which is nevertheless almost inevitably a failure if other programmers can't understand it.

Quantization
[In image processing/compression,] elimination of psychovisually redundant data, resulting in the loss of quantitative information, and hence compression. Also defined as the mapping of a broad range of input values to a limited number of output values.

Shading
[In image processing/compression,] process of calculating the color of a pixel or shading sample from user-specified surface properties and the shading model.

SPAM
An antisocial net behavior that intrusively spreads a message by mailing or posting it to newsgroups inappropriately (i.e., network junk mail). The proper way to advertise on the net is to make your information available in such an interesting fashion that people will want to read it.

Strip-mining
Reorganizing data in an array to change the number of dimensions. As an example, a normal image is a collection of RGB values in two-dimensions with a stride. A 4x3 pixel color image can be physically laid out as
RGBRGBRGBRGB
RGBRGBRGBRGB
RGBRGBRGBRGB
RRRRRRRRRRRR
GGGGGGGGGGGG
BBBBBBBBBBBB
where the image on the right is strip-mined from the image on the left by using stride 3. Both the images internally could be represented as a one-dimensional array with the specified views.

Supervisory Call
Switch mode from user mode to kernel mode. Transfers control to a routine that is part of the operating system code. Generally, the supervisory call places the user process in a blocked state.

Synapses
Special contacts formed by long, thin branches extending from the central body of each neuron to the branches of other neurons; the point at which a nervous impulse passes from one neuron to another.

Task
Execution of a process in its own address space.

Texturing
[In image processing/compression,] method of varying the surface properties from point to point in order to give the appearance of surface detail that is not actually present in the geometry of the surface.

Toroidal topology
[In textures,] phenomenon such that texture on the left edge must fit the texture on the right, and top edge must fit the bottom edge.

Widget
A reusable, configurable piece of code that operates independent of the application except through prearranged interactions.

Xt
The X Toolkit Intrinsics is a library layered on Xlib which provides the functionality from which the widget sets are built. An ``Xt-based'' program is an application which uses one of those widget sets and which uses Intrinsics mechanisms to manipulate the widgets.