linuxcnc 2.9.2 (live) on the intel n100 cpu

^^^ Recommend x100$ ^^^

Good to hear.

I've been running mine, making parts for a few days now with no issues, Running kernel 6.7.
Setting the IRQ affinity of the Mesa LAN interface to the isolated core is a must, I've found.

What kind of temperatures are you getting on that passive cooling while idling/working? Not really a linuxcnc issue, but I've considered using a machine like this as a simple firewall where passive cooling would be nice.

Thermal characteristic of the passive system is +10~12dC above ambient temperature while idle. e.g. if ambient temp is 20dC, the cores will idle at 30~32dC avg. In a fun and real-life scenario, running Linuxcnc will have the cores up to 50~55dC at ambient 20dC constant with that fanless and fat passive heatsink. Not all bad design!

Aside that N100, the networking perf of the ath9k (wireless) and r8169 (gigabit) are quite rewarding. Highly recommend (honest). Thanks to you and Hakan for the heads up, nice one guys. 

On the down side, that fatty heatsink radiates cold back in quite effectively. It's currently 5.5dC in my location, where the N100 is idle into (the backyard garage to be precise). If the CPU see sudden stress at those <10dC low temps, thermal shock may/will occur. And so you could say the passive unit is suitable for indoor at =>20dC only, ideally.

Not that anyone's running metal-on-metal below 10dC anyway. But to be mindful of... 

image missing https://i.postimg.cc/gk83ktNG/Thermal.png

I was thinking to get an orange pi5 but saw these mini industrial pcs on aliexpress
that have 2 lans and rs232/422/485 ports on board can run vanilla linux
without patches mods that need arm boards.
What mini pc from aliexpress you suggest to get?
(with 2x lan / rs232/485 ports/ 8gb ram at least)

Nah, don't do that (rpi5). Go for an industrial kit hands down - straight up official debian iso install & drivers supported, common/standard bios. 

Not an Alibaba member and so it's going to be hard for me to be useful with that request. What I can do is push the seller/manufacturer contact I got mine from (taobao). Grab that visual (business contact) and send that to a few of your alibaba sellers - as many as you can and request for the exact same unit to be shipped out. Reality is these dudes all know each others and/or they're all from the same place anyway. They'll find it for you I'm not even worried...

In a meantime I'll shoot an msg to my contact tomorrow and ask if he has an Alibaba store (or know of anyone who carries his product line). I'll update if anything.

image missing https://i.postimg.cc/VkKnrRkJ/taobao.png