<br><font size=2 face="Courier New">Hi Jan,</font>
<br><font size=2 face="Courier New"> thanks for the input. will look
into it.</font>
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<br><font size=2 face="Courier New">Regards</font>
<br><font size=2 face="Courier New">Deepa.<br>
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<td><font size=1 face="sans-serif"><b>kiszka@rts.uni-hannover.de</b></font>
<p><font size=1 face="sans-serif">15.10.2004 18:14</font>
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<br><font size=1 face="sans-serif"> An:
deepa.vijayaraghavan@mbtech-group.com</font>
<br><font size=1 face="sans-serif"> Kopie:
rtai@rtai.org</font>
<br><font size=1 face="sans-serif"> Thema:
</font><font size=1 face="Arial">Re:
rtnet code in rtai_24.1.12 (from denx)</font></table>
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<br><font size=2><tt>Paolo Mantegazza wrote:<br>
> deepa.vijayaraghavan@mbtech-group.com wrote:<br>
>><br>
>> Hello, Thanks a lot for the details.<br>
>> One newbie question:<br>
>> The code you have provided is an interface that enables calling
the linux<br>
>> kernel socket interface directly from the RTAI module. Am I correct?<br>
>> How is RTNET different from this? I mean, since RTNET is hard
real <br>
>> time, I<br>
>> think it does more in terms of converting the drivers etc., to
enable <br>
>> hard<br>
>> realtime. Is my understanding correct?<br>
>> Hence, when I use the kernel socket calls, I do not have hard
real time.<br>
>> For my application this interface is probably what I need. But
as a <br>
>> person<br>
>> new to all this, I am just curious to learn & understand more.<br>
>> If you could point me to some documents/links that explain more
about<br>
>> this(normal kernel drivers & hard realtime drivers), it will
be great!<br>
>><br>
<br>
Hard real-time networking like RTnet basically has to fulfil these <br>
requirements:<br>
<br>
o Bounded execution time in all real-time code paths, both in the<br>
drivers and in the stack. Setup and shutdown can typically
remain<br>
non-real-time.<br>
<br>
o Strict resource management (bandwidth, CPU time in common code
paths,<br>
packet buffers, etc.)<br>
<br>
And additionally when doing communication over unmodified Ethernet:<br>
o Media access control which reliably avoids collisions (when using<br>
hubs) or congestions (in switches)<br>
<br>
Some more information can be found on rtnet.sf.net. And for even more <br>
details about how RTnet actually achieves this, you are on the wrong <br>
mailing list ;).<br>
<br>
> Correct, the functions provided are not for real time, they use plain
<br>
> Linux.<br>
> <br>
> I think there is no need for a more specific documentation. When in
the <br>
> need of using both Linux and RTNet for the same application you have
to <br>
> care of the coding. In RTAI netrpc.c there is the simple way we adopted.
<br>
> An example application integrating Linux and RTNet networking can
be <br>
> found at: http://www.aero.polimi.it/~mbdyn/mbdyn-rt/index.html.<br>
> <br>
<br>
You can use Linux networking on top of RTnet, i.e. in spare time without
<br>
interfering with critical data.<br>
<br>
Jan<br>
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