Roland Bengtsson wrote: > > Hi, I'm a student from Sweden that study computer science att Halmstad > H�gskola http://www.hh.se/english. > I would be thankful if someone would take the time and give your view of this. > > Right now I'm writing a paper about Linux and realtime. I'm trying to give > a brief overview of what is available today and what the future have in > mind. I also try to explain the technical differences between the systems, > advantages and disadvantages. I have read a paper from QNX > http://www.qnx.com/literature/whitepapers/reallinux.html. They said of > course that their solution is the best:-) > > Even if they don't mention RTLinux directly it's obvious that they mean > RTLinux when they compare different solutions. In short they say that the > main disadvantages of RTLinux is: > > 1. Duplicated coding effort. As there are two kernels running there's a > need for drivers > in the realtime kernel if the service want be deterministic. This > means also that more memory is needed for the extra code. > 2. Realtime tasks aren't protected by a MMU like ordinary Linux-tasks. > 3. Limited portability of realtime tasks. > etc. > > It was interesting to see your view of this and maybe if you have som > shortcomings in QNX as this is two different approaches on the same > problem. And now my own questions about RTLinux... > > 1. What are the main reason that the standard Linux-kernel isn't > preemptable from the beginning? > Performance? > > 2. Realtimetasks all share their userspace and aren't memprotected, right? > Isn't it possible to implement this in some way. Honestly I don't think > RTLinux will success in critical processes if this situation remain. > > 3. "Hardware context switching provided by x86 is not used." This sentence > is from page 14 on http://www.rtlinux.org/documents/RTLinux.ppt. Is there > any reason for this? > > Regards Roland
Have a look also at "www.aero.polimi.it/projects/rtai" where you can find a lot of native compatibility with QNX. Paolo. -- [rtl] --- To unsubscribe: echo "unsubscribe rtl" | mail [EMAIL PROTECTED] OR echo "unsubscribe rtl <Your_email>" | mail [EMAIL PROTECTED] -- For more information on Real-Time Linux see: http://www.rtlinux.org/
