> > I am baffled by this discussion. Not so much by the discussion but that it appears no one actually knows what is going on other than that something is running on something. > > > > LinuxCNC relies on a real-time kernel in one of three flavours. RTAI, > > Xenomai or PREEMPT-RT.
So what's the difference then between RTAI, Xenomai or PREEMPT-RT? Again a simple description. And how are those different from what comes with Raspian in stock Linux form. I understand that the Pi is closed architecture while the Beagle is open so the there is a MachineKit port for the Beagle and that port takes advantage of the two PRU processors while Raspian has a faster 'feel' to it because it's got better Video and 4 cores. Clearly desktop Linux has some sort of RTOS (compared to single user CP/M-80, CP/M-86, MSDOS, WIN-386) since it allows multiple users to sign in. More like MP/M-86 which I ported to S-100 hardware for a customer way back in the early 80's. So along comes, finally, the GNU (GNU is Not Unix) compilers and from that the Linux OS. Certainly a Real Time Operating System (RTOS) but not Hard Real Time. Maybe more like Windows where a user gets processor time until it issues a system call whether that be to rewrite the screen, deal with the file system or a delay on a timer. At that point the OS takes over and does what it needs to do before going back to the user program. So unless there is something significantly different between RTAI, Xenomai or PREEMPT-RT, that is the subject of PhD dissertations, why are there still 3 of them? John ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
