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What Is Real-Time?

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  • Written By: N. Madison
  • Edited By: Bronwyn Harris
  • Last Modified Date: 19 October 2014
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In computing, real-time refers to a time frame that is very brief, appearing to be immediate. When a computer processes data at this speed, it reads and handles data as it is received, producing results without delay. For example, a website that is updated in real-time will allow its viewers to see changes as soon as they occur, rather than waiting for updates to be visible at some later date.

A non-real-time computer process does not have a deadline. A real-time system, on the other hand, is expected to respond not just quickly, but also within a predictable period of time. A good example is a car’s anti-lock break system. An anti-lock brake system is expected to release a vehicle’s brakes, preventing dangerous wheel locking, in a predictably short time frame.

Unfortunately, there are times when real-time systems fail to respond as desired. Such a process fails when its task is not completed before its deadline. In computing, there is no grace period given because of other demands on a system. Deadlines must be kept without regard to other factors; they are considered mission critical.

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When a process is considered hard real-time, it must complete its operation by a specific time. If it fails to meet its deadline, its operation is without value and the system for which it is a component could face failure. When a system is considered soft real-time, however, there is some room for lateness. For example, in such a system, a delayed process may not cause the entire system to fail. Instead, it may lead to a decrease in the usual quality of the process or system.

Hard real-time systems are often used in embedded systems. Consider, for example, a car engine control system. Such a system is considered hard because a late process could cause the engine to fail. These systems are employed when it is crucial that a task or event is handled by a strict deadline. This is typically necessary when damage or the loss of life may occur as a result of a system failure.

Soft real-time systems are usually employed when there are multiple, connected systems that must be maintained despite shifting events and circumstances. These systems are also used when concurrent access requirements are present. For example, the software used to maintain travel schedules for major transportation companies is often soft real-time. It is necessary for such software to update schedules with little delay. However, a delay of a few seconds is not likely to cause mayhem.

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anon351308
Post 5

A real time system is a system that ensures the exact time requirements for a job. If a real-time system does not complete a task in a certain time, it may cause a breakdown of the entire system it is running. Some applications require services within a time period: industrial control system, automobiles, airplane guidance and medical devices.

There are two types of real time systems: hard real-time systems and soft real time systems.

sherlock87
Post 3

Many video games also function in real time. While different in some ways from computing real time, the idea is still that the game and the story are processing your actions and then continuing at the same rate you are making decisions for your character and deciding things. It is pretty much the gaming opposite of the kind that have things like cut scenes to jump ahead in the story or use turn-based battles and things to give you more time; real time video games are all about the game player's ability to react.

ShadowGenius
Post 2

Real time strategy games on the internet require immediate response from various computers. The players on these computers are expected to be able to perform and think in correspondence with the real-time, forming a strategy for victory. This has become like massive online chess, with a vast array of details and operations.

mitchell14
Post 1

Real time also is involved in a lot of television and movies. For example, the popular television show "24" was centered around the idea of twenty-four episodes, each happening in an hour of real time. Most television and movies skip through things, anywhere from hours and days to years, following a more episodic than chronological time structure.

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