linuxcnc version for an old pc

Hi,
I don't know anything of linux and linuxcnc, but I'm interested to test linuxcnc in my new cnc diy machine.
I'm starting from zero and I've read some basic information: I think is a very complicated situations for a beginner.
Two version currently mantained, 2.6 and 2.7, there are various versions of Ubuntu and Debian, is a very hard task to decide the correct way to proceede!!
Furthermore my hardware pc is old: pentium IV, 2GHz, 762MB ram, parallel port to drive step motor.
I would kindly ask what is the suitable version of linuxcnc from 2.0 to 2.6 (or 2.7), the suitable version for OS (ubuntu, debian) with number of version.

thanks

You might want to start here...
linuxcnc.org/docs/2.7/html/getting-start...etting-linuxcnc.html
then

boot the computer from the Live/Install Image and choose the Live boot option. Once the computer has booted up you can try out LinuxCNC without installing it.

Start there and then run the latency test to see if there is a problem.

Also note that 8.04 often runs better than 10.04 on older hardware however your upgrade path is limited.

Rick G

Hi Rick G,

thanks for Your support!!
I've run the Latency Test on 2.7 and the result is very bad: max jitter is about 250,000,00 ns.
But I think this result is very predictable, because the hardware is 10 years old !!
Now my question is: it is possible to run an old version of linuxcnc (probably the earliest version) to
achieve an acceptable cnc functioning ?
Or I need for a newer pc!!!

thanks for all

dll67

Hi Rick G,

thanks for Your support!!
I've run the Latency Test on 2.7 and the result is very bad: max jitter is about 250,000,000 ns.
But I think this result is very predictable, because the hardware is 10 years old !!
Now my question is: it is possible to run an old version of linuxcnc (probably the earliest version) to
achieve an acceptable cnc functioning ?
Or I need for a newer pc!!!

thanks for all

dll67

Your next step would be to troubleshoot the latency problem.
Some good info here...
wiki.linuxcnc.org/cgi-bin/wiki.pl?TroubleShooting
Also try 8.04 as if often runs better on older hardware, you may not be able to update to the latest version, but the stable version in 8.04 may have all the features you need.

Rick G

Just because the PC is old doesn't mean that it can't run the latest Linuxcnc. A PC capable of adequate latency with an old Linuxcnc Ubuntu 10.04 live CD install still will probably be able to achieve adequate latency with a Wheezy install (when properly configured). The fact that the newer Wheezy ISO often posts worse latency scores than the older installation CDs is over stated and the difference is usually insignificant. The real trick is getting your PC and the software configured correctly to work together to get good (or good enough) latency scores. And you are likely to have the same problems even with an older installation CD. This is a very complicated subject, that is different for every PC and no single tutorial has all the answers.

There are certain things that will almost always need to be done when configuring the PC. Such as making sure all power saving features, wait states, and hyperthreading are turnned off in the BIOS. If your old PC is a single core and has less than 2G of ram try to choose a kernel that is suited for it. (such as for the Wheezy install on your old PC be sure to choose the 3.4-9-rtai-486 kernel and not one of the PAE ones.)

I am not sure exactly would boot up with the current Live ISO on an old computer but in a virtual machine configured for 1 core, 1024mg memory, just now it only gave me the live option 3.4-9-rtai-686-pae. So if it doesn't give the right option when you install you'll have to do it yourself after words, Installing it is simple with Synaptic, just search for rtai-486, mark for install, reboot, then choose the right option in the grub menu.

Maybe that isn't as easy as I thought. Installing the kernel was not hard, but then Linuxcnc would not start. Have to play with it a bit,