A Presentation by Theodore Ts'o
Traditionally, real-time systems have been primarily associated with data acquistion or industrial control systems, where the systems were often smaller embedded systems, running specialized RTOS's that generally didn't have the full functionality found in a general purpose OS. The CONFIG_PREEMPT_RT patches by Ingo Molnar have enabled a new kind of real-time systems, which are based on Linux and which support SMP processors, TCP/IP, and the ability to run enterprise middleware, including databases and middleware. This talk will talk about how the author's real-time team at IBM was able to take a fairly large (at the time we started, over 1.7 megabytes of patch) open source kernel patch being developed by the community, join the community, stablize the code, and produce a commercially supported product offering based on that patch to support a real-time JVM. This talk will discuss the technology behind the real-time patches, how they differ from other approaches, the challenges we encountered in trying to create a supportable product which was dependent on a rapidly moving development stream that had not yet even been merged with mainline, what this patch has allowed us to do with it and our real-time Java offering.