lock up

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lock up

Brit a small shop with no attached quarters for the owner or shopkeeper
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005

lock up

[′läk ¦əp]
(graphic arts)
To position a form in the frame in which type and plates are locked up for letterpress printing.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.


(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 are more tolerant of application bugs. However, operating systems themselves are not 100% foolproof, and bad applications can cause operating systems to crash; a major motivation for running in a virtual mode (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.

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.
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References in periodicals archive ?
Sources said RPO Muhammad Fayyaz Dev, hours before his transfer, has paid a surprise visit to Police Station (PS) New Town checked the record of criminals, the pending FIRs, lock ups and Front Desk.
According to the sources from Jail due to the high strengthen of prisoners in these lock up the basic human rights are being violated due to huge number of prisoners and that the provincial government has failed to ensure provision of basic facilities.
Gavin said he was baffled as to how the thieves got in to the secure lock ups without leaving any sign of damage.
IN A MAJOR step aimed at ending human rights violations in jails and in custody, the Supreme Court on Friday directed the Centre and all states to install CCTV cameras in all prisons within a year A bench headed by justice TS Thakur also asked the states to consider installing the cameras in all police stations and lock ups.
ISLAMABAD -- Although sham Indian parliamentary elections are over in the Indian Occupied Valley, several Hurriyet leaders, activists and youth continue to be in police lock ups without any rhyme.