A Linux kernel can be replaced with a compatible kernel with hard real-time performance characteristics, such as the LynxOS RTOS. This real-time kernel must:

• support all the facilities of a Linux kernel;
• remain fully preemptive and reentrant;
• have a real-time scheduler; and
• have bounded execution time for interrupt handlers.

The advantage of using a real-time replacement kernel such as LynxOS is that there are no limits on size or complexity of the real-time application code. Third-party software not originally envisioned for real-time use could be invoked by real-time tasks. Linux programmers come up to speed quickly in the real-time environment because the programming interfaces are the same.

With the advent of the Linux Standard Base, a binary interface standard, Linux is becoming less of a technology and more of a platform for running applications. Any operating system that meets the standard can run those Linux applications.

See also: Strategies for Developing Embedded Applications.