Dear Gurus,

I have 2 fundamental questions and I appologize in advance to burden you with 
more answering jobs stealing your precious development time, but at least the 
first question is crutial to our project.

1.)
Essentially the question deals with the problem, how long a Xenomai task in 
secondary mode can be delayed by normal Linux tasks. 
In detail : we plan to to have a lot of "near realtime" ethernet communication 
from within Xenomai using the normal Linux network stack (calling the normal 
socket API). The question now is, how our network communication is influenced 
by other Linux tasks performing also network communication, let´s say an FTP 
transfer ?
(I have heard about RT-Net, but as far as I understand it needs its own 
realtime domain and therefore a gateway to communicate with the outside world. 
We want to avoid this.)

I have created a scheduling scenario and I would ask you to have a look on it 
and to tell me whether it is correct or not. Thank you !
An corresponding question about this scheduling is : are there differences 
between a 2.4 and 2.6 Linux kernel ? (for our PowerPC plattform we intend to 
use the 2.4 kernel for performance reasons)

Scheduling scenario :
(I hope formating is not destroyed by email transfer)

Time moves downwards

v-Xenomai 
     v-Linux kernel
          v-Linux processes

          l1   Linux task1 running
     s1 < l1   Linux task1 makes systemcall
     s1        Linux task1 systemcall processed
-------------  Linux scheduling   
          l2   Linux task2 starts to run
     s2 < l2   Linux task2 makes systemcall
     s2        Linux task2 systemcall processed
+++++++++++++  Xenomai scheduling
x3             Xenomai task3 starts to run => primary mode
x3 > s3        Xenomai task3 makes systemcall => secondary mode
     s3        Xenomai task3 systemcall processed 
-------------  Linux scheduling => Xenomai task preemted
     s1        Linux task1 systemcall processed
     s1 > l1   Linux task1 systemcall ready => Linux task1 continues 
          l1   Linux task1 continues
-------------  Linux scheduling 
     s2        Linux task2 systemcall processed
     s2 > l2   Linux task2 systemcall ready => Linux task2 continues 
          l2   Linux task2 continues
-------------  Linux scheduling => Xenomai Task3 systemcall continued
     s3        Xenomai Task3 systemcall continued
x3 < s3        Xenomai Task3 systemcall ready => Xenomai Task contiunes
x3             but has been delayed by normal Linux tasks


2.)
This question is not so crucial, but nevertheless interesting :
Who are the people behind Xenomai (I did not find anything about this on the 
Xenomai webpage), what is their background (University, Company)and who impels 
/sponsors the Xenomai development (University, Company, Community)? 
I think I "identified" at least 2 core developers : Philippe Gerum and Gilles 
Chanteperdrix, but I don´t know very much more.
The background for this question is, to get a feeling, how future-proof the 
xenomai development is. As far as I can see open source projects often die or 
stall when the initiators decide that "growing flowers" is a much more pleasant 
job ;-).


Thank you for taking time to answer these questions, which are interesting to 
others too, I think !?

Best Regards
Roderik




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