[cletero]

Hi, I'm new to the whole Ubuntu/linuxcnc thing. After a lot of playing around I managed to install Ubuntu 10.04 and now I installed linuxcnc but when I try to run the latency test (without running linuxcnc, as indicated), the whole OS freezes and I have to restart. I tried searching Ubuntu forums for an answer but I guess it's full of advanced users who just cannot lay it in simple terms, so I ask here in case someone can give a step by step answer as to how to solve the problem. Please, no kernel, rtai, bla, bla talk. Although I'm not a programmer I have very good computer skills but being new to linux stuff, I need everything to be explained in simple terms or steps. Ej: go to applications/accessories/terminal and type bla bla bla. etc.

[PCW_MESA]

Hi, I'm new to the whole Ubuntu/linuxcnc thing. After a lot of playing around I managed to install Ubuntu 10.04 and now I installed linuxcnc but when I try to run the latency test (without running linuxcnc, as indicated), the whole OS freezes and I have to restart. I tried searching Ubuntu forums for an answer but I guess it's full of advanced users who just cannot lay it in simple terms, so I ask here in case someone can give a step by step answer as to how to solve the problem. Please, no kernel, rtai, bla, bla talk. Although I'm not a programmer I have very good computer skills but being new to linux stuff, I need everything to be explained in simple terms or steps. Ej: go to applications/accessories/terminal and type bla bla bla. etc.

Did you start with the live CD image?, that's by far the easiest software installation method. If the live CD install does not work, it may be some hardware incompatibility.

Probably the easiest way to solve hardware problems is start by choosing hardware that's known to work well with LinuxCNC before you begin. Because of the real time requirements, not every Motherboard will work well with LinuxCNC

[CaptainVee]

To expand on that:
The live cd mentioned in the previous post is the version found on linuxcnc.org.

This version has linuxcnc baked in and has the real time kernel. This means (hope I explain this correctly) that it can give priority to tasks that need to be timed well, like cnc.
Probably because of this I have had one instance where I asked too much of the pc in side tasks while running the mill. The pc froze but the mill kept on running and finished its task. I then had to force a shutdown...

This also means that other linux versions without the real time kernel can NOT run linuxcnc even though you may be able to install it.

So, if you have not used the live cd found here: Installing LinuxCNC

Use one of those .ISO files, burn to disk and run it. If the 10.04 version does not work, maybe the 8.04 version will.

Also important, due to real time issues with integrated videocards, laptops are generally useless for cnc-ing.

If you want to use it on a laptop, use the simulator found here:
LinuxCNC buildbot

What are the specs of the computer you are using?

[cletero]

Thanks for the replies. I had already installed Ubuntu 10.04 and had used the Lucid-install found on step 2 of "installing LinuxCNC". I had read something about the kernel having to do with the problem I'm having, and as CaptainVee mentions this in his post, I think I will have a go installing everything again from the live CD. I just didn't want to burn a cd if I could just download a file and use that instead. As far as my computer, it's AMD Athlon X2 processor, 2,71 Gz, 4GB RAM, plenty of harddrive space. Ubuntu/Windows startup. I plan to use xylotex 269 motors and driver with dremel and 1/4 inch screws for a start, just to see everything works fine and then I'll invest in 1/2 inch, 10 tpi acme screws and bosch router or trim router, haven't decided yet. I will keep you posted as to how it goes.

[cletero]

Thanks, installing from the live CD did the trick. I'm running the test now.

[cletero]

Took some time, but finally got things working, but now I run the latency test and get s****y results, max jitter goes up to 450000 just by opening firefox, 230000 just opening the terminal to run glxgears, 404000 running glxgears, etc. Once they are open, if I reset the latency test, it stays easily below 15000.
I'm running double boot system, XP and Ubuntu (from live CD install), but most importantly I have Nvidia GeForce 6150SE nForce 430 card, which as I read later in quick start guide is a no-no for running linuxcnc. RAM is 4GB, Athlon 7750 processor, so my questions are:
1) Is the Nvidia card responsible for the high latency results?
2) Is there anyway around this, or should I give up and go with Mach3?

If you need any more info, just let me know where to get it (I'm new to Ubuntu) and I'll post it ASAP.

I CAN'T waste any more time dealing with this, I need to get my machine running ASAP, and I don't care spending $175 on Mach3, just though a free controller was a better idea. But not sure if the high latency results mean Mach3 won't run properly either (on windows XP).

Thanks for any help,

Alfredo

[109jb]

Nvidia could be the problem but it could be something else too. The linuxcnc website has install information. Did you read it. It says:

"7. Nvidia Card configuration issues
The closed source nvidia drivers are known to be incompatible with realtime kernels. This has been reported to nvidia but they seem uninterested in fixing it, and because their drivers are not open source, nobody else can fix it either.

To get your nvidia graphics card working, edit the xorg.conf file in the /etc/X11 directory. At about line 66, in the section "Device", find a line that looks like: Driver "nvidia" , replace nvidia with "nv" or "vesa" (try "nv" first). If you have previously tried to use the nvidia driver, you must remove nvidia-related packages by issuing the following command from a terminal:

sudo apt-get --purge remove nvidia-glx nvidia-settings nvidia-kernel-common

There is at least one report that even when using the open source 'nv' driver, the latency test will show failures. "

You could get another video card too and eliminate this as a problem. PCI video cards are less than $10 on e-bay. ATI cards seem to be the choice here.

You can always install Mach3 and try it for free before buying. It will run up to 500 line of g-code before you have to buy it.

[cyclestart]

2) Is there anyway around this, or should I give up and go with Mach3?

The Mach3 demo will let you run the driver test. Seeing as the machine is already dual boot it wouldn't take long to test................
otoh
for less than the price of a Mach license you could build with an Intel Atom mb/cpu/gpu combo. It works well for me (and other users from what I've read). A D510MO is $50 on Amazon(Canada) atm, probably a similar price other places.

I think the post suggesting using hardware that's known to work is sound advice.

btw: the info on editing xorg.conf may be out of date. In fact I'm pretty sure it is.

[cletero]

Hi, thanks for the answers, I had read the install info about editing the xorg.conf file, but I misunderstood it (due to frustration, I guess), even if it's a far shot, I would like to try it before anything else, just have a concern: does this affect only the Ubuntu environment or will it also affect XP? Being a newby to the whole Ubuntu thing and dual boot systems, I better ask than be sorry later.

I tried to use an old computer that a cousin of mine has (sorry, can't remember its specs right now, but was Intel based) but for some reason it kept asking for a password at the beginning of the install, it previously had Ubuntu installed but even after we formatted it kept asking for a password! Any ideas?

Thanks again, guys,

Alfredo

[CaptainVee]

xorg.conf only affects ubuntu.

Have you tried installing the livecd with linuxcnc on the old computer? or was that the normal ubuntu cd?

Maybe the bios was password protected, that could be hard to beat...

Older computers are often a good choice, I use a P4 2 ghz pc which runs great.

[cletero]

Yes, I used the live cd with linuxcnc, ubuntu was already installed so we though that something to do with it, so my cousin formatted the computer and tried again as a fresh install and still gets asked for a password. Actually, I believe it's a P4 too, but not sure right now.

[cletero]

I did the xorg.conf modify and latency went down to 16000 even when opening firefox, playing music, installing programs and copying files.

But now I can't run glxgears, I get the following error message:

Xlib: extension "GLX" missing on display ":0.0".
Error: couldn't get an RGB, Double-buffered visual

And most importantly, I can't run my-mill either! I get a huge error message but can't find a way to copy it into a text file, it won't allow right-click copy or ctrl-c. So with my limited experience with Gimp image editor, I attach a picture of the error message. Hope it helps. But for some reason I only was able to upload a jpg, the png file kept been changed to jpg for some reason in the upload manager, so I left both anyway, the png is the one that doesn't finish with "2", but not sure if it will work properly.