Re: [Emc-developers] Crazy Talk [was: I am new here]

[EBo <eb...@sa...>]

Lars,

I'm just returning from ~three weeks traveling and weeding through 
many, *MANY* hundreds of emails.  I cannot remember if I already 
commented on this, but I am glad that you have been advocating for 
preempt-rt.  I've been doing the same behind the scenes for some time...

Thanks for the info on osadl.org.  I will have to look into this more 
when I get some time to break out.

   EBo --

On Fri, 30 Mar 2012 21:25:57 +0200, Lars Segerlund wrote:
> Which is why I have been trying to agitate for preempt-rt ..... it's
> now following mainline, and is available on ALL architectures since
> it's general ...
>
>  Still sometimes there are driver problems, but check out osadl.org 
> for ARM.
>
> / regards, Lars Segerlund.
>
> 2012/3/30 EBo <eb...@sa...>:
>> On Fri, 30 Mar 2012 11:36:04 -0500, Jon Elson wrote:
>>> Anders Wallin wrote:
>>>>> 2) How portable is the real-time code (ie: can it be compiled for
>>>>> Arm
>>>>> or PowerPC)?
>>>>>
>>>>
>>>> LinuxCNC uses the RTAI kernel/API. There are a number of
>>>> architectures
>>>> listed here https://www.rtai.org/
>>>> I don't know if anyone has made LinuxCNC work on other than x86 
>>>> and
>>>> x86_64
>>>
>>> I sent Torsten Koschorrek of RTAI a Beagle Board about 18 months 
>>> ago,
>>> and as
>>> you can see, there is no ARM Cortex-A8 RTAI available yet.  I can't
>>> believe it has taken
>>> this long!  There is an RT-Preempt kernel that was done by some
>>> French
>>> guys, but I don't
>>> know if it has suitable latency for LinuxCNC, but it almost 
>>> certainly
>>> is
>>> good enough
>>> for a system with attached hardware (not software stepping).
>>
>> <soapbox>
>>
>> That is what I was planning to work on with artek's NURBS hardware. 
>>  If
>> you get similar stuff working with RT-preempt.  The biggest problem 
>> with
>> RTAI is that the patches are to invasive to the kernel and each time
>> even a minor update to the kernel happens it needs to be majorly 
>> tweaked
>> by hand and (from my experience) never just updates.  Then there are 
>> all
>> the bad feelings between the RTAI community and those 
>> using/promoting
>> RT-Linux.  Personally I was caught in the crossfire and was left 
>> with no
>> love of RTAI.  I am glad that there is a decent alternative.  BTW, 
>> for
>> technical correctness, RTAI and RT-Linux will *always* be faster and
>> have less latency than the preemptive and similar approaches, but
>> getting RTAI working is truly a pain unless you only use the 
>> precompiled
>> CD/DVD version, and sometime that is not a realistic option.
>>
>> <\soapbox>
>>
>>   EBo --