Is linux a "real time" operating system?

[Chadsxe]

My Instructor asked me this question in clsss the other day I had no answer for him. I have been searching the internet for en explanation but not haveing to good of luck. I am confused and was wondering if someone could explain it to me or point me in the correct direction. Thanks

[kjordan2001]

No, I don't believe it is. Real-time operating systems are more what you'd find in cars or airplanes for controlling essential things, so Real-time operating systems are more in the embedded type systems. They are usually more simplistic than Linux or Windows.

[davemania]

In terms of scheduling? no. Most PC OS are designed with good response time in mind and they generally use algorithms such as round ribbon scheduling. You only find real time OS when timing is absolutly critical such as aeroplane control or lab experiments etc.

But of course a developer can always implement a real time alogirthm into Linux.

[rezza Veteran]

IIRC, there has been some work to make the kernel more real-time, such as pre-empting work, schedulers, and latency. Normally, linux isn't real-time however.

QNX is anexample of an RTOS.

[Daybreak]

List of real-time operating systems on Wikipedia here. More explanations exactly on what a RTOS is also available there.

Linux isn't. There are patches floating around to patch the kernel to have real-time support, but I don't think you'll find any mainstream distributions using them.

[Shadrack]

Feels pretty "real-time" to me. And by real-time i mean it isn't turn based. Especially in a multi-user environment. It isn't like I run a processes, and every other person logged in get their turn to launch their processes. It's all pretty much real time.

i'm just being a jerk... don't listen to me.

[CaKeY]

  nic said:

Feels pretty "real-time" to me.  And by real-time i mean it isn't turn based.

584943757[/snapback]

:laugh: :laugh: :laugh:

[Zerosleep]

Too many RPGs eh?

[FireRabbit]

The stock linux kernel is not real-time, but people have developed patches that add support for this. I know someone who controls CNC and other similar equiptment using a realtime linux system.

I think this is the correct URL: http://www.fsmlabs.com/products/openrtlinux/

[dduardo]

There has been some work on a real time linux like this:

http://source.mvista.com/linux_2_6_RT.html

[kyro]

i think the question asked here is answered. but want to add..linux is so fast and responsive that when asked is it RTOS people have to think before deciding .... this is a nice compliment to linux :) <-- linus travold's smile.

[LaNcom]

As already explained, the stock Linux kernel is no RTOS. There's a recent patch by MontaVista, based on some research done by the university of the federal armed forces, Germany. And there's Lynx, a Linux-compatible RTOS. But a RTOS is only suitable for certain (mostly embedded) systems, like cars, plant management, network equipment, military systems, DAW equipment and such, not really suitable for a desktop. Realtime systems usually don't perform as well as non-realtime OS's, and their latency is not neccessarily very low, but determined (like, any request will be served in at least, eg, 10ms - no matter what load you put on the machine).

[kyro]

^ nice info LaNcom :yes: