Intel H81

Same thing, will install but will just not boot, cursor on top left, I have and older PC, Shuttle brand as well and it boots with no issues, I am thinking it has to do with the display drivers, ie 4k uhd display, again thanks for all your help.

I will still use this pc/box for around the work place just wont be using it for LinuxCNC. I am trying to find a tiny pc with network compatibility to go with a Mesa network FPGA board.

If you plan to use a Ethernet FPGA card, you might try Ubuntu 14.04 on the H81 MB since in
any case you will need to download/compile LinuxCNC master to run the hm2_eth card, and it looks
like you will need a current kernel.

Strange, I have just tested it on my Gigabyte H81M-HD3, that I use everyday with win7, only because the latency times.
It starts without any problems, from the DVD. Ive got latency times in the range of 8000 with it (with integrated grafik).

I just bought a Gigabyte GA-H81-D3 (with a pentium G3258 which is a bargain Haswell chip)
Booted from the Wheezy Hybrid iso image on a USB stick with no fuss at all (default BIOS settings)
Great latency on Preemt-RT (~21 usec) and RTAI (~7 usec)

What you mentioned earlier worked Peter, sorry I have been all over the place lately with work. How do you like the PC? Lots of potential from such a tiny box.

Is it normal, that preempt have higher latency times than rtai. I have seen on my other board, that preempt downgrades
the clock rate by 1/3 from 2 GHz to 1,328GHz that results in a slower latency time from 4500 to 8000.

If Preemt-RT changes the CPU clock frequency (or perhaps calculates it wrong),
thats probably due to a kernel bug with your specific hardware. I have never seen this behavior
and have run Preemt-RT on at least 10 different systems.

Latency in Preemt-RT is typically longer than RTAI or Xenomai because it works in a different way.

RTAI and Xenomai are dual kernel systems that run a special real time kernel that has Linux as one
of its tasks. The advantage of this is that the real time kernel is small and well defined (and designed from
the start for real time) so can have minimal latencies. One disadvantage of this system is the real time
kernel cannot use standard linux device drivers.

Preempt-RT uses a single kernel (in fact Preempt-RT is really a patch set that is applied to the stock Linux kernel source)
The patch set makes the kernel full preemptable so high priority tasks can preempt low priority tasks.
this allows use of normal linux drivers (such as Ethernet drivers) in a real time context. It does result in higher
latencies so may not be suitable for things like software step generation

Good to know, that RT-preempt runs only on 1 kernel, anyway as much kernels are available.
In this case it should be better, next time I need a board for this purpose I buy one with less kernels, but higher clock rate.
But the H81 board have a latency of 8000, while the celeron Board with only 2/3 of the clock rate have a slightly faster latency of 7000.

For Ethernet/Preemt-RT faster is better and latency (as show by the latency test) is not very important (as long as its not greater than say 50-60 usec)
For a step/dir system that will run at 1 KHz servo thread CPU choice is not critical, but if you need the fastest servo thread you can get, CPU speed is important.

Also I think there's a language difficulty here, when I say kernel I mean a software construct versus a processor core
Both RTAI and Preemt-RT support multi-core processors, though there may be latency advantages to restricting the real time tasks to 1 processor

Thank you all for your insight into this, but I have come to the conclusion there is a lot of installing and modifying of drivers for the Shuttle DS81 to even work on any current distros. I seem to get a working system with Arch Linux or newer Ubuntu 14.04 but again lot of modifying of drivers to get the system actually stable. Back to the drawing board......