Scanything for Linuxcnc ??

mancavedweller · Post by **mancavedweller** » Wed Jul 22, 2015 8:06 am

Hi Les,

I've recently bought your Scanything.

Due to Mach3 future not looking so good (sales will end), and Mach4 seeming to be rather buggy and only half developed, I'm looking at moving over to Linuxcnc.

I don't suppose you have any plans for creating a Scanything that will work with Linuxcnc ??

Thanks,

Keith.

Post by **Les Newell** » Wed Jul 22, 2015 10:48 am

Connecting to LinuxCNC is an issue due to licensing restrictions. I have had a couple of requests for this so I will investigate further.

mancavedweller · Post by **mancavedweller** » Wed Jul 22, 2015 1:09 pm

Thanks Les,

I've noticed a few other guys "abandoning ship" with Mach3/4. I wonder if there's going to be a bit of a growing migration to Linuxcnc as a result.

Keith

Vmax549 · Post by **Vmax549** » Thu Jul 23, 2015 4:41 am

(;-) I think Tormach and CandCNC have already blown all the rules/restriction for Lcnc out the door.

(;-) TP

Post by **Les Newell** » Thu Jul 23, 2015 7:51 am

No they haven't. It is perfectly legal to use and modify and add functions to LCNC for commercial purposes as long as you make the source code for your changes available. I know Tormach have done this and I'm sure CandCNC will as well. Others will be able to copy and use the code for their own purposes. The tricky issue is that the GPL is 'viral'. If I use any GPL code in mine, all of my code automatically becomes GPL and has to be made available.

Both Tormach and CandCNC are primarily selling hardware so this is fine for them. As I am primarily selling software it is a bit more of a problem to make my source code available. There are various ways around this issue but I need to be sure what I do is both legal and doesn't upset the authors of LCNC.

Vmax549 · Post by **Vmax549** » Thu Jul 23, 2015 1:32 pm

Les it DEPENDS on HOW you attach your app TO Lcnc that detemenes IF your app falls under teh license or NOT. That is clearly covered. IF you hook in directly THEN it becomes PART of the core IF you hook in remotely( Loosely defined) then you are NOT part of the core app and do not fall under teh license.

I don't think you would have a problem with ScanAnything as teh CORE does not NEED your app to do all it does. BUT the GUI side is required to make the core work properly.

I think it is one of those things that will eventially be tested in court to be absolutely SURE.

Just a thought, (;-) TP

Vmax549 · Post by **Vmax549** » Thu Jul 23, 2015 3:40 pm

Now I am NOT a LAWYAH but if you look at teh majority of the court cases that were to TEST the GPL MOST were SETTLED long before a summary judgement was issued SO it has never REALLY been tested. The Judgement WOULD have set the president of the merits of teh GPL. As is it just left more work for a LAWYAH. They always try to excape before a judgement is issued that way they can attempt to try it again and again.

HECK if most of the cases were actually cleaned up there would be little left for judges and LAWYAHs to do SO that ain't gonna happen.

(;-) TP

viesturs.lacis · Post by **viesturs.lacis** » Tue Jul 28, 2015 6:05 pm

Les Newell wrote:The tricky issue is that the GPL is 'viral'. If I use any GPL code in mine, all of my code automatically becomes GPL and has to be made available

AFAIK the usual way to solve things like this is splitting your software in 2 parts and distributing like 2 separate packages:
1) first part: your actual software (scanything) - licence it as you like and keep closed source
2) second part: whatever additions are needed to LinuxCNC to import/use the output of scanything - this could be a contribution to LinuxCNC code base as some kind of new HAL component or simply python script or anything similar; AFAIK LinuxCNC requires any contributed code to be licensed under "GPLv2 or later" which should not be a problem for some intermediary scripts.

And no - all of your code does not automatically become GPL, you can licence it under different terms, it is that if you use GPL-ed code, GPL requires to make _all_ the code to be available to any person that purchased your product. And that is what Tormach does - you can get a DVD with source code for PathPilot (their version of LinuxCNC) after you have paid for that software. But AFAIK PathPilot is not licenced under GPL.