abend


Also found in: Dictionary, Thesaurus, Medical, Legal, Financial, Acronyms.

abend

[′ab·end]
(computer science)
An unplanned program termination that occurs when a computer is directed to execute an instruction or to process information that it cannot recognize. Also known as blow up; bomb; crash.

ABEND

(jargon)
/o'bend/, /*-bend'/ ABnormal END. Abnormal 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 capitalised, 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 computer late on Friday when they want to call it a day, and hence is from the German "Abend" = "Evening".

abend

(ABnormal END) Pronounced "ab-end." An abend is an unexpected termination that causes the computer, smartphone or tablet to stop responding. The abend occurs either when the processor is presented with instructions or data it cannot recognize, or a program tries to address memory beyond a defined boundary. Abends are generally the result of erroneous software logic in the application or operating system (see anomaly).

Crash, Freeze, Lock Up and Hang
A "crash" occurs when the computer issues a "fault" and deliberately halts that line of execution. The terms "freeze," "lock up" or "hang" may refer to software that is actually still running but has erroneously wound up in an endless, internal loop that renders the program useless. In practice, the terms "crash," "freeze," "lock up" and "hang" are used synonymously. See infinite loop.

Bad Hardware Can Look Like Bad Software
A serious hardware failure will stop a computer-based device that has no redundant components. For example, a short circuit on the motherboard will halt the operation; however, a failing memory cell can cause an instruction to point to an erroneous location, making it look like a software failure.

It Depends on the OS
If the abend occurs due to a bug in an application and the operating system is not resilient, the computer locks up and has to be rebooted. Modern operating systems attempt to halt only the offending application and allow the remaining applications to continue. As operating systems evolve through the years, they become more bug-free themselves and more tolerant of application bugs. However, all operating systems are not 100% foolproof, and bad applications do cause operating systems to crash; a major motivation for virtualizing computers (see virtualization and virtual machine).

A Miracle It All Works
If you consider what goes on inside a computer, you might wonder why it does not crash more often. An ordinary home computer can easily have 64 billion memory (RAM) cells. Every second, millions of them switch their status between charged and uncharged (1 to 0; 0 to 1). If only one cell fails, it can cause an instruction to be invalid, and an abend can occur. See head crash, GPF, active area and transistor concept.



Abending
The green blocks are machine instructions executed by the CPU one after the other until a branch (jump) instruction breaks the sequence and points to an instruction elsewhere in the program. Abending (crashing, hanging, etc.) occurs when the program erroneously points outside of its address space, typically due to bad logic.
References in periodicals archive ?
(47) Gabriel Abend (2006): "Styles of sociological thought: Sociologies, epistemologies, and Mexican and U.
The rapid rate of fashion change in the apparel industry will generate demand for U.S.-based firms that have the capability to respond quickly to demand fluctuations (Abend, 2000).
Abend will work with Ted Bregar to focus on business development.
Abend was halfway down the Garden State Parkway, on his way to teach a class and do rounds at Union (N.J.) Hospital, when he placed his usual Tuesday morning call to his father.
100-01 where "Mittag" and "Abend" are rendered as "midday'" and "evening" rather than the surely more accurate "south" and "east." More seriou sly, one can argue that Martin has minimized an important potential line of inquiry by conflating "Empfindsamkeit" and "Empfindelei" in the single translation "exaggerated sensibflity" on page 2, failing to adequately render the negative '-el' suffix.
wie das Milieu uns betort, in seinen Hohen und Tiefen der Abend ist
* Abend Diagnostic Snapshot (ADS), a detailed report provided by the isCOBOL Runtime Environment, for troubleshooting and root cause analysis
Third awards: Rahi Punjabi, Advanced Math and Science Academy, Which Soil Type is the Best?; Jeremy Abend, Bancroft, Shapin' Up to the Wind; Syifa Rahmadianputri, Al-Hamra, Cold Feet; Daniel Clemson, Bancroft, Egg Base Jumping; Omaima Afzaal, Al-Hamra, Let the Sun Shine!; Justin Delgado, Advanced Math and Science Academy, What Makes A Good Biofuel Source?; Bilal Baara, Alhuda Academy, Worcester, Visual Memory vs.
Lang's title Fine Fahrt ins Blaue, is taken from a Bunter Abend cabaret programme of 1952 and has been chosen for the various meanings it conveys apart from that of the obvious journey into the unknown which life in Australia meant for so many Germans and Austrians.
["Long Range Facilities Planning and Design Implementation for Students with Disabilities: A Guide for New Jersey School Districts" was written in collaboration with: Allen Abend, Diana Autin, Sue Sobel Gottesman, Paula S.
Abend. "I just got an iPod, and I have about 5,000 CDs, everything from classical to metal music," he said.
Multi-millionaire Ian Ashley Smith was driving out of a concealed driveway from a pounds 750,000 property he owns in DamWood in leafy Scarisbrick village, when a motorcyclist came round abend 90 metres away.