Real-time computing: Difference between revisions

Revision as of 19:16, 16 November 2023

Revision as of 04:10, 4 February 2024

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'''Soft real-time systems''' are typically used to solve issues of concurrent access and the need to keep a number of connected systems up-to-date through changing situations. Some examples of soft real-time systems:

* Software that maintains and updates the flight plans for commercial [[airline]]rs. The flight plans must be kept reasonably current, but they can operate with the latency of a few seconds.

* Live audio-video systems are also usually soft real-time. A frame of audio that's is played late may cause a brief audio glitch (and may cause all subsequent audio to be delayed correspondingly, causing a perception that the audio is being played slower than normal), but this may be better than the alternatives of continuing to play silence, static, a previous audio frame, or estimated data. A frame of video that's is delayed typically causes even less disruption for viewers. The system can continue to operate and also recover in the future using workload prediction and reconfiguration methodologies.<ref>{{cite journal | title = Real-time reconfiguration for guaranteeing QoS provisioning levels in Grid environments | journal = Future Generation Computer Systems | volume = 25 | issue = 7 | pages = 779–784 | date = July 2009 | doi = 10.1016/j.future.2008.11.001| last1 = Menychtas | first1 = Andreas | last2 = Kyriazis | first2 = Dimosthenis | last3 = Tserpes | first3 = Konstantinos }}</ref>

* Similarly, video games are often soft real-time, particularly as they try to meet a target [[frame rate]]. As the next image cannot be computed in advance, since it depends on inputs from the player, only a short time is available to perform all the computing needed to generate a frame of video before that frame must be displayed. If the deadline is missed, the game can continue at a lower frame rate; depending on the game, this may only affect its graphics (while the gameplay continues at normal speed), or the gameplay itself may be slowed down (which was common on older [[Third generation of video game consoles|third-]] and [[Fourth generation of video game consoles|fourth-generation consoles]]).