Migration from Mach3 for plasma

Hi,
I currently have a 5x5ft plasma cnc table running a Hypertherm 65A plasma with a Mach3 controller. Dell Optiplex, Win XP, Parallel port interface, Proma THC 150, Chinesium drivers, Nema23 steppers.
I'd like to upgrade the controller to LinuxCNC, mainly for having Linux running on the machine, being able to send files over the network etc. Every other computer at the shop runs linux as well, so this is the only one left on win.
It seems like there are not too many plasma users running linuxCNC, can I expect similar performance to what I have right now running Mach3?
I'd like to use Xenomai for the rt os, since I have some prior experience with it. Not picky about linux distro, but would prefer rh/fedora/centos with KDE.
Thank you

(I don't have a plasma machine) But there are a number of people here running plasma with Linuxcnc, and the impression I've gotten is that it can be quite good at it.

However my opinion is your distro preference will make installation quite unnecessarily difficult. Not that it can't be done, but neither Fedora or Xenomai are officially supported. (But the desktop environment shouldn't matter.) I would strongly encourage you to try Debian or a Debian based distro. With the easiest install being using one of the official iso's available here with Linuxcnc and the required real time kernels already set up. That said I would be very tempted to install Debian Testing (Bookworm) and then install Linuxcnc from the Debian Repos.

Yes, or better.  I'm not running LCNC plasma, but I've been (silently) following the development and refinement of Qtplasmac for a while. I suspect LCNC is a far superior motion control system to Mach3 for plasma machines.

Have a look here:
linuxcnc.org/docs/devel/html/plasma/qtplasmac.html

Something to keep in mind, which is not always obvious to new LCNC users (like myself), is that LCNC is the motion control software but you don't generally interact directly with LCNC except during initial configuration.  The vast majority of user interaction is done through a separate GUI program (such as QtPlasmaC).  So if you don't like one GUI and don't feel like modifying it, you usually have other choices of GUI programs (or variations of the same program) to choose from.

Thanks!
I'm mainly interested in running Xenomai vs preempt rt patch to get better latency figures, after all I'll be using the parport interface - at least at the beginning. I've been using Xenomai for many years in motion control, familiar with building kernels and modifying drivers etc.
Ive got a few Dell optiplex PCs for testing. I'll get started with building a 'stock' Linux CNC system first, then build an experimental box on the side.

Just so you know, if you are migrating from Mach3 to Linuxcnc and continuing to use the parallel port, Stepconfig (a Linuxcnc configuration wizard for parallel port configs) has the ability to import a Mach3 configuration XML file and convert it into a Linuxcnc config. It might not be able to handle all of the details of a plasma config, but it should at least transfer all of the basic stepper, and limit io and set them up using the same settings as the Mach3 config was using. This should at least give you the basic framework to build your config from.

The QTPlasmac config is the way forward for you.  It will be a bit foreign to you but its supported by sheetcam
linuxcnc.org/docs/devel/html/plasma/qtplasmac.html
It needs to run V 2.9 master branch of linuxcnc
It will support your Proma THC
But it will probably do better if you use a Mesa THCAD-10 to read the torch voltage so Linuxcnc can do the THC function internally
And you will get even better results if you ditch your breakoutboard with a Mesa 7i96 or 7i76e (if you can find one due to global chip shortages)

Linuxcnc requires a real time operating system eithe PREEMPT_RT or RTAI (which is close to obsolete now)

Also for where you want to go, read the building Linuxcnc chapter in the 2.9 docs. Its pretty straight forward to do. I did a video on a chromebook you might like to watch