Editing Real-time computing (section)

== Real-time and high-performance ==
Real-time computing is sometimes misunderstood to be [[high-performance computing]], but this is not an accurate classification.<ref name="Stankovic1988">{{Citation |title=Misconceptions about real-time computing: a serious problem for next-generation systems |first=John |last=Stankovic |year=1988 |periodical=Computer |volume=21 |issue=10 |publisher=IEEE Computer Society |doi=10.1109/2.7053 |page=11|s2cid=13884580 }}</ref> For example, a massive [[supercomputer]] executing a scientific simulation may offer impressive performance, yet it is not executing a real-time computation. Conversely, once the hardware and software for an anti-lock braking system have been designed to meet its required deadlines, no further performance gains are obligatory or even useful. Furthermore, if a network server is highly loaded with network traffic, its response time may be slower, but will (in most cases) still succeed before it times out (hits its deadline). Hence, such a network server would not be considered a real-time system: temporal failures (delays, time-outs, etc.) are typically small and compartmentalized (limited in effect), but are not [[catastrophic failure]]s. In a real-time system, such as the [[FTSE 100 Index]], a slow-down beyond limits would often be considered catastrophic in its application context. The most important requirement of a real-time system is consistent output, not high throughput.

Some kinds of software, such as many [[Computer chess|chess-playing programs]], can fall into either category. For instance, a chess program designed to play in a tournament with a clock will need to decide on a move before a certain deadline or lose the game, and is therefore a real-time computation, but a chess program that is allowed to run indefinitely before moving is not. In both of these cases, however, high performance is desirable: the more work a tournament chess program can do in the allotted time, the better its moves will be, and the faster an unconstrained chess program runs, the sooner it will be able to move. This example also illustrates the essential difference between real-time computations and other computations: if the tournament chess program does not make a decision about its next move in its allotted time it loses the game—i.e., it fails as a real-time computation—while in the other scenario, meeting the deadline is assumed not to be necessary. High-performance is indicative of the amount of processing that is performed in a given amount of time, whereas real-time is the ability to get done with the processing to yield a useful output in the available time.