Linux.com has published a short Q&A with Steven Rostedt, kernel developer at Red Hat and maintainer of the stable Linux real-time patch. Rostedt discusses issues such as “hard” vs “soft” real-time, what the Preempt-RT patch can and can’t do, and how to get started using it.

Linux.com editor Libby Clark writes…

When embedded projects call for for a real-time operating system, Linux developers often turn to PREEMPT-RT, the real-time kernel patch, to get it done.

“The PREEMPT_RT patch (aka the -rt patch or RT patch) makes Linux into a real-time system,” said Steven Rostedt, a Linux kernel developer at Red Hat and maintainer of the stable version of the real-time Linux kernel patch.

The thing is, in most cases real-time requirements on embedded projects can be met without turning to a real-time operating system, he said via email. To developers, a real-time system “does what you expect it to do when you expect it to do it.” That’s all.

Clark then asks, and Rostedt answers, these questions about the RT patch…

• As Dave Stewart said in an ABS panel discussion, people often assume that embedded means real-time but that’s not always the case. He said, “There’s been a dawning realization that you can achieve the vast majority of what you need to with embedded without a classically-oriented real-time system.” Do you agree?

• When and how does real-time Linux come into embedded development?

• I heard from Steve Sakoman that embedded Linux doesn’t work when the device has hard real-time requirements (and in some cases, any real-time requirements). How does the real-time patch meet those requirements when embedded Linux falls short?

• How is the RT patch used in embedded development?

• What’s your advice to embedded developers who want to use the RT patch?

• When does it make more sense to work with a distro that has already incorporated the RT patch, versus starting from scratch?

• What challenges still remain for RT Linux in embedded development and how are they being addressed?

Read LIbby Clark’s complete Q&A with Steve Rostedt here.

Rostedt’s ELC presentation, “Inside the RT Patch,” can be viewed below. The accompanying slides can be downloaded here (PDF file).

Learn more about real-time Linux

For lots of information about the PREEMPT_RT patch and real-time Linux in general — including FAQs, tips, how-to’s, community news, and more — visit the Real-time Linux Wiki.