New NI-RIO 3.5 FPGS Interface C API

[J_Bangasser]

Will the newly released NI-RIO 3.5 FPGA Interface C API for Linux work when you have DAQMx installed?

Reading the Readme file for the new NI-RIO 3.5 FPGA Interface C API for Linux, it states:

“To ensure the successful operation of National Instruments RIO products, you must use a kernel configuration that 

recognizes only up to 4 GB of physical memory.”

Doesn’t the DAQMx drivers require a stack > 4 GB?

[rsw]

The NI-RIO 3.5 will not work on 32 bit kernels with PAE (Physical Address Extensions) and >4GB of RAM, this isn't a limitation of NI-RIO 3.5 but of NI-KAL, this has always been the requirement. It should work fine with DAQmx installed as well.

[J_Bangasser]

But from my knowledge, the DAQMx won't work if the stack is 4GB.  It needs a stack > 4GB. We have RedHat Enterprise 5.4 running with a stack > 4 GB and our DAQmx and NI-KAL is OK (or at least as far as we can tell). Does DAQMx use NI-KAL?

[irwan]

Technically, NI-PAL (which DAQmx depends on) on 32-bit won't work when the addressable amount of memory is > 4GB, due to the data type we use internally for physical address, so we're limited to 32-bit. If you have more than 4GB memory, something will fail to load.

[rsw]

I'm a little confused where this >4GB is coming from for DAQmx, it does use NI-KAL as do all NI drivers under Linux to communicate at that layer, the readme.txt shows the minimum system requirements well under the 4GB limit: http://ftp.ni.com/support/softlib/multifunction_daq/nidaqmx/8.0.1%20Linux%20Only/readme.txt

[JoeFriedchicken]

I believe the confusion is based on system RAM versus kernel stack. As Irwan said, NI-PAL requires that fewer than 4 GB of system RAM be installed/recognized. DAQmx, on the other hand, requires an 8kB kernel stack for its internal data structures.

Joe

[J_Bangasser]

My apologies.  Joe is correct.  I confused stack size and RAM size.  I did not read the Readme file correctly.

Thanks Joe!