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Real-Time Linux Developers Unite On API

Posted by Hemos on from the agreement-is-good dept.

Markar writes "Developers and programers decided to support EL/IX by Cygnus Solutions as the API for Real-time Linux. Only one dissenter was counted after the vote was taken. The lone dissenter wanted to wait for further developements. PlanetIT is carrying more information. " You can also check out more information about the conference as well.

1 of 57 comments (clear)

  1. Real Time System definition by sec · · Score: 5

    Since some people are asking what a realtime system/OS is, here goes:

    A realtime system is a system in which the response time of the system to an external event is predictable and bounded. That is, if a user presses a button, a realtime system will guarantee that the system takes whatever action is associated with that button press in a given time, or less.

    This does not necessarily mean that the system is fast or responsive. For example, the design spec could say that if the user presses the button, the system must respond in 5 seconds or less. As long as the system always responds within 5 seconds, it is still a realtime system, even though most people wouldn't think of it as such.

    If the system fails to respond within the specified time frame, it is considered a design failure. As such, it is used mainly in things like industrial or vehicle control systems, where failing to respond within the specified time can have catastrophic consequences.

    A realtime OS is simply an operating system designed for use in realtime systems. Because of strict constraints on response times, some harsh tradeoffs must be made -- ones that users of desktop and server operating systems would find hard to fathom.

    For example, a realtime filesystem is very difficult, if not impossible, to design, because some filesystem operations can have a potentially unbounded completion time. Usually, any processor cache is disabled, because, although the cache greatly decreases the average execution time, it can actually _increase_ the worst-case execution time, and it makes it very difficult to determine how long a piece of code is going to take to execute.