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'.

  1. 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.
  2. 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.''
  3. 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.

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.

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

A frozen image of what the process is doing at a certain time

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

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]

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's 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.

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]

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.

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

A set of essential operating routines used by the operating system (usually hidden from the user) to perform important system tasks, such as managing the system memory or controlling disk operations. More information on kernel.

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


  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.

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.

Execution of a
process in its own address space.