Dell Optiplex 745 suitability

Greetings All,

Just thinking out loud, as I may still continue with the "original plan", but...

I've been casually looking for a nice Atom based motherboard to continue/complete my control with for a few weeks now, when I realized today that I have a Dell Optiplex 745. They are listed in the latency tables in the Wiki, but not with the best of numbers. It's not the mini ITX I was shooting for, but it _IS_ here _now_.

Additionally, I am considering moving all the PC components into the monitor pendant, which would free up a fair amount of space in the main cabinet. So, the difference in size would not be as intrusive or constraining.

My question is about the overall suitability of the Foxconn LS-36 motherboard and components in the Optiplex 745, with LinuxCNC. I have been told that numbers such as those in the latency page for the 745 ( which agree with the one I have, by the by ) are not TOO horrible as long as I am running the Mesa cards, but is there anything I can do to otherwise improve it?

Thanks for any insights you might be able to offer.

Hi

First thing to do is your own latency test and then try what the tester states he did not do.

ie. Turn off all things in BIOS that might interfere with latency and use the isolcpus kernel parameter on the boot line.

The sort of things to try in BIOS are all in my FAQS at the top of this section.

But if you are just running a servo thread and using the board for motor control, encoders, PWM etc. it will probably work OK pretty much as it is

regards

I tried to find a way to pass the arguments during boot, but did not see where or how to do that with the live CD.

You can only change the kernel boot line on the fly, if you get a GRUB menu up, I don't think you do if running from the Live CD, because there are no choices, so it jumps straight in.

I would use the hybrid.iso with Debian Wheezy and 3.4.9-rtai and LCNC 2.6.2. I have been able to get Wheezy to run on everything from a P4 to i7
The kernel and new realtime seems to give much better latency than the old 2.6.32-122-rtai from the Ubuntu 10.04 install
www.linuxcnc.org/binary.hybrid.iso

When you have installed, you can change the grub boot line.
That is a seperate topic wiki.linuxcnc.org/cgi-bin/wiki.pl?The_Is..._Parameter_And_GRUB2

regards