On 04/12/2019 05:39 AM, Nicklas Karlsson wrote:
I have been thinking in similar paths, there is NML communication between
parts. Then trying to separate I got the impression maybe real time part
work but axis did not work properly. I also get the impression real time
performance have gotten better for ordinary Linux run on ordinary computer
which would make separating less useful but still good.

As far as I know, splitting the mostly-RT part of LinuxCNC from the display/interpreter part has been possible since the early days of EMC2 with HAL. But, the NML system in LinuxCNC sends a LOT of data back and forth when it may not be necessary. Machinekit changed most of this over to 0mq, which creates a global state, and then allows various "subscribers" to tell it what specific info they need. 0mq then sends ONLY that required info to each subscriber. My understanding is the move to 0mq has not been totally finished (as of the last I heard) but it did allow much greater separation of the many pieces of LinuxCNC onto separate computer nodes. Part of their impetus on this was to enable multiple machines in a workcell to be coordinated by a central process.

On the other hand, Machinekit works pretty well on a Beagle Bone. Yes, the screen and keyboard can sometimes be just a little bit laggy, but it seems to be usable. And, it works fine on relatively cheap mini-ITX PC motherboards.


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