What LinuCNC is doing in its core was done on relatively simple
systems without GUI long time ago. I believe that it's time for
architectural change. Split GUI from RT section, and move away from
the dependence on terrible PC architecture to industrial SBCs make
sense to me. Imagine, we still have DOS functions in BIOS! And that is
"emulated" in virtual machines in the data centers these days!
LCNC already allows this. You have the RT side (HAL) and whatever GUI
you want to use to talk to it.
What you are talking about is moving all of the RT side to a different
hardware platform. I have done a lot of embedded work with micros from
8051 to modern ARM. I will agree a dedicated platform can provide much
better timing. However the big problem is compatibility and long term
availability. Say the RT side moves to platform X. You are now tied to
that platform. If it goes out of production you are dead in the water.
It wouldn't be a huge task to develop an open source LCNC hardware
platform but then who is going to organize manufacture and distribution?
PCs have been around for a long time and they aren't going away for a
long time. I have done quite a lot of maintenance and repair of CNC
machines, some PC based and some using dedicated hardware. If the
dedicated hardware dies and the parts are no longer available you have a
big paperweight. If a PC dies you can replace it easily.
If you want hardware stepping look at the Mesa boards. They work
extremely well, moving the critical timing to hardware. Of course you
are then tied in to the Mesa platform but those boards are pretty simple
and should be pretty reliable. I've used quite a few on several
machines, with two failures so far. One was my own fault. I accidentally
shorted one of the 3.3V signal lines to 24V. The other failure was a
rather odd one on a motor driver. Peter was very helpful and sent me the
information I needed to fix it myself. Not many hardware vendors are
willing to provide schematics and that level of support.
The great thing about the LinuxCNC architecture is that you can make
have the PC/dedicated hardware split anywhere you want. Mesa for
instance leaves the 1kHz loop on the PC while moving the critical timing
to hardware. IMHO this is the sweet spot. Nearly all motherboards can
handle the 1ms loop without issues.
I would rather see a resurrection of Multibus like architecture with
modern CPUs and peripherals for CNC use than running "special test" to
find out which freaking motherboard with parallel port on PCI card is
suitable for Linux RT kernel and LinuxCNC. Intel designed Multibus for
RT use and supported it for many years.
And where is Multibus now? It's dead. PCs were around before Multibus
and they have long outlived it.
Is LinuxCNC going to stay as it is and end up as other old computer
technologies described in IEEE article "Inside the Hidden World of
Legacy IT Systems"
https://spectrum.ieee.org/computing/it/inside-hidden-world-legacy-it-systems
Umm, that article actually emphasizes my point. PC hardware is current
and PC compatible hardware will continue to be available for a very long
time. Whatever other platform you choose is likely to be long dead
before PC hardware disappears.
Les
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