After earthquake INGV site down - 5 April 2009

telecommunication Telecommunication is the transmission of information by various types of technologies over wire, radio, optical, or other electromagnetic systems. It has its origin in the desire of humans for communication over a distance greater than tha ...

s and related engineering (including

computer networking A computer network is a set of computers sharing resources located on or provided by network nodes. The computers use common communication protocols over digital interconnections to communicate with each other. These interconnections ar ...

and programming), the term timeout or time-out has several meanings, including: * A network parameter related to an enforced event designed to occur at the conclusion of a predetermined elapsed

time Time is the continued sequence of existence and events that occurs in an apparently irreversible succession from the past, through the present, into the future. It is a component quantity of various measurements used to sequence events, t ...

. * A specified period of time that will be allowed to elapse in a system before a specified event is to take place, unless another specified event occurs first; in either case, the period is terminated when either event takes place. Note: A timeout condition can be canceled by the receipt of an appropriate time-out cancellation

signal In signal processing, a signal is a function that conveys information about a phenomenon. Any quantity that can vary over space or time can be used as a signal to share messages between observers. The '' IEEE Transactions on Signal Processing' ...

. * An event that occurs at the end of a predetermined period of time that began at the occurrence of another specified event. The timeout can be prevented by an appropriate signal. Timeouts allow for more efficient usage of limited resources without requiring additional interaction from the agent interested in the goods that cause the consumption of these resources. The basic idea is that in situations where a system must wait for something to happen, rather than waiting indefinitely, the waiting will be aborted after the timeout period has elapsed. This is based on the assumption that further waiting is useless, and some other action is necessary.

Examples

Specific examples include: * In the Microsoft Windows and

ReactOS ReactOS is a free and open-source operating system for amd64/ i686 personal computers intended to be binary-compatible with computer programs and device drivers made for Windows Server 2003 and later versions of Windows. ReactOS has been noted ...

command-line interfaces, the timeout

command Command may refer to: Computing * Command (computing), a statement in a computer language * COMMAND.COM, the default operating system shell and command-line interpreter for DOS * Command key, a modifier key on Apple Macintosh computer keyboards ...

pauses the command processor for the specified number of seconds. * In

POP Pop or POP may refer to: Arts, entertainment, and media Music * Pop music, a musical genre Artists * POP, a Japanese idol group now known as Gang Parade * Pop!, a UK pop group * Pop! featuring Angie Hart, an Australian band Albums * ''Pop'' (G ...

connections, the server will usually close a client connection after a certain period of inactivity (the timeout period). This ensures that connections do not persist forever, if the client crashes or the network goes down. Open connections consume resources, and may prevent other clients from accessing the same mailbox. * In HTTP persistent connections, the web server saves opened connections (which consume

CPU time CPU time (or process time) is the amount of time for which a central processing unit (CPU) was used for processing instructions of a computer program or operating system, as opposed to elapsed time, which includes for example, waiting for inpu ...

and

memory Memory is the faculty of the mind by which data or information is encoded, stored, and retrieved when needed. It is the retention of information over time for the purpose of influencing future action. If past events could not be remembered ...

). The web client does not have to send an "end of requests series" signal. Connections are closed (timed out) after five minutes of inactivity; this ensures that the connections do not persist indefinitely. * In a timed light switch, both

energy In physics, energy (from Ancient Greek: ἐνέργεια, ''enérgeia'', “activity”) is the quantitative property that is transferred to a body or to a physical system, recognizable in the performance of work and in the form of hea ...

and lamp's life-span are saved. The user does not have to switch off manually. *

Tablet computer A tablet computer, commonly shortened to tablet, is a mobile device, typically with a mobile operating system and touchscreen display processing circuitry, and a rechargeable battery in a single, thin and flat package. Tablets, being comput ...

s and

smartphone A smartphone is a portable computer device that combines mobile telephone and computing functions into one unit. They are distinguished from feature phones by their stronger hardware capabilities and extensive mobile operating systems, whic ...

s commonly turn off their

backlight A backlight is a form of illumination used in liquid crystal displays (LCDs). As LCDs do not produce light by themselves—unlike, for example, cathode ray tube (CRT), plasma (PDP) or OLED displays—they need illumination ( ambient light or a s ...

after a certain time without user input.

Examples

See also

References

Further reading