microkernel task scheduler -> RTOS scheduler info

Hello All

My company is in the beginning phase of rewriting an embedded task-driven operational flight program from an ancient processor (Z8000 in ASM) to a modern language that will run on a PowerPC processor.

My question is this: Does anyone have any documentation or paper information on what types of issues, pitfalls, and obstacles usually pop up when going from a dedicated, mature microkernel to another (commercial) OS. I predict the RTOS will be a commercial RTOS from OSE, Wind River or Green Hills. What I'm specifically looking for is (in addition to lessons learned and general stuff mentioned above) information on how to perform the task switching and interrupt arbitration handled by the old tasking kernel on a new POSIX type task switching OS such as OSE, VxWorks or Integrity.

Any thoughts, horror stories, or documents are more than welcome.

Thanks all.

Do you know what a "microkernel" is? QNX, as one example, is a commercial, microkernel-based RTOS, which is POSIX compliant and is intended for embedded applications.

The issues will be at least partly dependent on how generalized your old OS is or whether apps functionality was incorporated into it. If the partitioning was kept very strict, the issues should be minor. If the line was allowed to blur, well ...

Do you need DO-178B certification? That may be an issue in selection if needed.

VxWorks from Wind River has a steep learning curve coming from your current environment. Not only will you need to learn the OS, but also Workbench. Have you used Eclipse? Point your browser to

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for a preview of Workbench--it is based on Eclipse. I believe Wind River only supports the GNU and Diab C/C++ compilers, so those better be your "modern language."

Some of the RTOS vendors do have papers/info on porting on their sites. Exception: Wind River. You basically cannot get any info from their website unless you are a registered customer.

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has a lot of info available, including a VxWorks Porting Guide, as I recall. ;-)

~Dave~