DAQmx Base w/ Realtime Linux

[jbetten]

Hi,

I've been a long time user of Comedi for device support with RTAI, a hard realtime extension of Linux. I would like my users to have the ability to use M-Series cards; however, without register-level documentation that won't be possible with Comedi. So I've been looking at DAQmx Base, but there is one glaring problem... The library can only be accessed from user space, and most of the function calls lead to system calls, which are unacceptable in realtime. So I am wondering... is there any possiblily that the kernel space driver interface will be published? Specifically the defines and structs associated with nNIKAL100_ioctl. After all the function is opensource, it is just difficult to interface without reverse engineering the user space library.

Thx,
-JB

[Sean_C.]

Hello JB,

R&D is currently looking into releasing a DAQmx driver for Linux. If we do release this, it would work in the kernel space. We are also looking into providing RLP support for M Series. Do you have a large opportunity that is contingent on this?

Regards,
Sean C.

[jbetten]

Hi Sean,

I wouldn't say I have anything contingent on this... it is just that:
1) Getting data into and out of the DAQ card is by far our biggest bottle neck, so it would be nice to have the fastest card/driver combo possible.
2) When I'm asked to recommend hardware I'm not entirely comfortable recommending something that is both slower and more expensive than existing technology, i.e. E-Series vs. M-Series.
3) We have funding for a programmer over the summer to improve our device support offerings, so while it might be possible to have him/her reverse engineer the ioctl interface it would be a blatant violation of the EULA, and maybe more importantly a very boring and unfulfilling summer.

-JB

[Sean_C.]

Hello JB,

DAQmx Base is currently the only support offered for M Series on Linux. However, R&D is currently looking into other driver support options which would greatly simplify and expedite your application development. Keep an eye out for these new drivers. In the meantime, you will need to use DAQmx Base.

Regards,
Sean C.

[JoePatlak]

Greetings;

We are currently using RLP with an E-series board using RTLinux, with great efficiency and success. I'm trying to use an M-series board, but can't use DAQmx base because it doesn't seem to match either the performance or kernel-side interface that I need.

Is the rlp model for the M-series so different? How can NI ship products without documenting their basic control?

In any case, JB, if you start reverse engineering, I would be willing to share our current code.

Take care,
Joe.