Odd observation... PC will only run 32bit RTAI and not 64Bit??

I have a Dell Optiplex 780 SFF that I have been using to run my mill. I have a HDD with mint 17.3 32 with the 3.4.9 RTAI kernel with Linuxcnc 2.7.8. I created another setup on a T3500 Dell precision so that I could upgrade to 2.9(master) for the ability to use TCP for 5 axis control on Linux Mint 19.3 64 4.14.148 RTAI kernal. In the t3500 I get excellent latency numbers with both configurations showing below 10 us. I get the same results in the 780 with the 32 bit setup but if I use the 64 bit setup the latency test gives me all zeroes. Has any one else run into this problem? The most descriptive error I get for the command line is that Linuxcnc failed to load because of a configuration error, but the same configuration files work in the T3500?

The 780 probably isn't fully 64 bit compatible. They are pretty old.

That's very possible, Do you know how I would go about checking?(Ideally in linux). The 780 runs 64 bit windows 10 fine. The processor is 64 bit compatible and the processor is compatible with the motherboard as best as I can tell it has a Q45 chipset.

mill@mill ~ $ sudo /proc/cpuinfo
[sudo] password for mill:
sudo: /proc/cpuinfo: command not found
mill@mill ~ $ lscpu
Architecture: x86_64
CPU op-mode(s): 32-bit, 64-bit
Byte Order: Little Endian
CPU(s): 4
On-line CPU(s) list: 0-3
Thread(s) per core: 1
Core(s) per socket: 4
Socket(s): 1
NUMA node(s): 1
Vendor ID: GenuineIntel
CPU family: 6
Model: 15
Model name: Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz
Stepping: 11
CPU MHz: 2394.198
BogoMIPS: 4788.39
Virtualization: VT-x
L1d cache: 32K
L1i cache: 32K
L2 cache: 4096K
NUMA node0 CPU(s): 0-3
Flags: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc arch_perfmon pebs bts rep_good nopl aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm lahf_lm dtherm tpr_shadow vnmi flexpriority

I really have no idea what the problem could be. Best guess when you compiled the kernel for other system you choose a setting that may have made it incompatible with this one. But that is only a guess (and probably not a very good one at that.) I have never even tried to compile my own kernel, mostly because then I'd have to install Linuxcnc from source, and it just never seemed worth the bother.

PS a big thanks to everyone who has put in the time and effort to give us pre-compiled real-time kernels and matching binary installations of Linuxcnc, so us less gifted humans can use it.

Tommylight, I have tried using mint 19.1,2,3 with the precompiled files in www.linuxcnc.org/temp. they work fine on the t3500 and don't on the 780. I haven't been able to compile the latest RTAI kernal for 32 bit. That is as far as I can tell the only differences between them. I am using the same drive between both machines and have used the same settings in both BIOS's. It is completely baffling to me as to why one pc works and the other one doesn't(with the same drive). Normally I would just swap the pc's but I can't fit the t3500 in place of the 780 SFF.

tommylight wrote:

Todd wrote:

Last one i did ended up at nearly 900MB, hence i scoured the web and found that KONA-RT version from an audio release of Linux.

This sounds like the same thing as is mentioned in this thread

I have no idea why this happens to random (but few) users. And I can assure that I did follow the instructions exactly, but this happened on only one computer.

This sounds like the same thing as is mentioned in this thread

I have no idea why this happens to random (but few) users. And I can assure that I did follow the instructions exactly, but this happened on only one computer.

akb1212, I don't understand how this relates to my particular issue...? I don't believe that I get that error. When I run a HDD in the 780 that I have verified working in the T3500(ie the latency test works and I can open up Axis and jog things around without errors) the OS boots up fine but the latency test doesn't work and linuxcnc tells me that there is a problem with the configuration. BUT the same config works in the t3500 so I am at a loss.

It was tomylights config that ended up at 900 MB that was similar, not yours (hence why I quoted his post). What happens in some (random?) hardware is that it puts on error reporting or something that makes the image 10 times a large as normal.

My point is that there are some hardware that ends up making differences to the configs that makes a big difference. In my (and tomylights) case this ended up with an image that was so bit it's impossible to start it!

So on a general note, (exactly!) the same procedure ends up with different configs with different hardware.