[Xenomai-help] xenomai on em2440

[Xenomai-help] xenomai on em2440

[Łukasz Sacha]

Hello!

I'm just starting to play with xenomai. My first goal is to install it
on my em2440 (similar to mini2440) board.
I could use some solid guidelines on where to start as there are many
tutorials out there - on mini2440, on xenomai, on arm, on i-pipe and I
don't even know which should I follow.

So please be patient with me and please help me get started.

Regards,
--
Łukasz Dragilla Sacha

Re: [Xenomai-help] xenomai on em2440

[Gilles Chanteperdrix]

On 10/29/2011 10:38 PM, Łukasz Sacha wrote:
> Hello!
> 
> I'm just starting to play with xenomai. My first goal is to install it
> on my em2440 (similar to mini2440) board.
> I could use some solid guidelines on where to start as there are many
> tutorials out there - on mini2440, on xenomai, on arm, on i-pipe and I
> don't even know which should I follow.
> 
> So please be patient with me and please help me get started.

I would recommend downloading xenomai 2.6.0-rc5 (soon to be release
2.6.0), and follow the installation guidelines called README.INSTALL in
the tarball. The instructions are for ARM in general, but there is not
much specific to a board or SOC, except the kernel configuration.

If you have some issue once xenomai is installed, you can try the
TROUBLESHOOTING file contained in the tarball, or the FAQ, if that does
not help you ask questions on the mailing list (you can also try to
browse the mailing list archives for similar issues).

Then, you will have to choose which skin you want to use, if it is
posix, you may read the following document:
http://www.xenomai.org/index.php/Porting_POSIX_applications_to_Xenomai
If you choose the native skin, you may read the following document:
http://www.xenomai.org/documentation/branches/v2.3.x/pdf/Native-API-Tour-rev-C.pdf

Finally, for detailed api documentation, try the doxygen API
documentation available here:
http://www.xenomai.org/documentation/xenomai-head/html/api/index.html

We keep links to all these documents when you click "Start here", on
xenomai main page.

Regards.

-- 
                                                                Gilles.

Re: [Xenomai-help] xenomai on em2440

[Łukasz Sacha]

Thank you for your answer.
I'm starting to read. I just to to understand one more thing first
because it not clear to me from the wikifaq/howtos.
I've fount an overview of real time linux solutions here:
http://www.ibm.com/developerworks/linux/library/l-real-time-linux/
Xenomai is said to be a thin kernel approach. Is this right?
If so, would you explain to me what is a skin on this picture?
My guess is it's the way "real time tasks" part looks like/acts like.
Am I right?

However there is another diagram shown in the Chameleon RTOS pdf -
this does not include the user space.
What is the user space? Is it or can it be a "regular linux", like
emdebian for example?

Can xenomai have multiple skins at the same time?

Please help me understand.

regards,
--
Łukasz Dragilla Sacha



On Sun, Oct 30, 2011 at 01:13, Gilles Chanteperdrix
<gilles.chanteperdrix@xenomai.org> wrote:
> On 10/29/2011 10:38 PM, Łukasz Sacha wrote:
>> Hello!
>>
>> I'm just starting to play with xenomai. My first goal is to install it
>> on my em2440 (similar to mini2440) board.
>> I could use some solid guidelines on where to start as there are many
>> tutorials out there - on mini2440, on xenomai, on arm, on i-pipe and I
>> don't even know which should I follow.
>>
>> So please be patient with me and please help me get started.
>
> I would recommend downloading xenomai 2.6.0-rc5 (soon to be release
> 2.6.0), and follow the installation guidelines called README.INSTALL in
> the tarball. The instructions are for ARM in general, but there is not
> much specific to a board or SOC, except the kernel configuration.
>
> If you have some issue once xenomai is installed, you can try the
> TROUBLESHOOTING file contained in the tarball, or the FAQ, if that does
> not help you ask questions on the mailing list (you can also try to
> browse the mailing list archives for similar issues).
>
> Then, you will have to choose which skin you want to use, if it is
> posix, you may read the following document:
> http://www.xenomai.org/index.php/Porting_POSIX_applications_to_Xenomai
> If you choose the native skin, you may read the following document:
> http://www.xenomai.org/documentation/branches/v2.3.x/pdf/Native-API-Tour-rev-C.pdf
>
> Finally, for detailed api documentation, try the doxygen API
> documentation available here:
> http://www.xenomai.org/documentation/xenomai-head/html/api/index.html
>
> We keep links to all these documents when you click "Start here", on
> xenomai main page.
>
> Regards.
>
> --
>                                                                Gilles.
>
>

Re: [Xenomai-help] xenomai on em2440

[Eric Noulard]

2011/10/30 Łukasz Sacha <dragilla@domain.hid>:
> Thank you for your answer.
> I'm starting to read. I just to to understand one more thing first
> because it not clear to me from the wikifaq/howtos.
> I've fount an overview of real time linux solutions here:
> http://www.ibm.com/developerworks/linux/library/l-real-time-linux/
> Xenomai is said to be a thin kernel approach. Is this right?

More or less.
In the next drawing "Nano-kernel" approach you see a reference
to ADEOS, ADEOS/I-pipe is the hardware abstraction layer used by Xenomai
see: http://www.xenomai.org/documentation/branches/v2.3.x/pdf/Life-with-Adeos-rev-B.pdf

So from the cited article point of view Xenomai is more like a
nano-kernel approach than think kernel.

> If so, would you explain to me what is a skin on this picture?

A skin is an API on top of the "thin kernel (ADEOS + Xenomai Nucleus) "
which is offered to Real-Time tasks.
There is FAQ for that question
http://www.xenomai.org/index.php/FAQs#What_is_a_Xenomai_skin.3F

which part of this answer does you not understand?

> My guess is it's the way "real time tasks" part looks like/acts like.
> Am I right?
> However there is another diagram shown in the Chameleon RTOS pdf -
> this does not include the user space.
> What is the user space?

Which diagram ? on which page of the document?

User space vs Kernel Space is the usual privilege separation of
operating systems:
http://en.wikipedia.org/wiki/User_space

> Is it or can it be a "regular linux", like emdebian for example?

As far as I know Emdebian is more about stripping down a classical linux
than making it real-time. Xenomai as a sub-kernel approach which runs
one linux system instance (for which there may not be hard realtime guarantee).
So Linux is not a Xenomai skin it's kind of low-priority task running along with
Xenomai.

That said may be it's possible to apply xenomai patch set to
Emdebian, but I really don't know.

> Can xenomai have multiple skins at the same time?

Yes Xenomai may have mulitple skins
(see slide 5 of  http://www.xenomai.org/images/c/c6/Xenomai-OSMB-2007-01.pdf)
but I don't know if a single application may use different skins at
the same time.
I never tried myself so I let other answer that one.

Why would you want to have/use multiple skin?

-- 
Erk
Membre de l'April - « promouvoir et défendre le logiciel libre » -
http://www.april.org

Re: [Xenomai-help] xenomai on em2440

[Łukasz Sacha]

> A skin is an API on top of the "thin kernel (ADEOS + Xenomai Nucleus) "
> which is offered to Real-Time tasks.
> There is FAQ for that question
> http://www.xenomai.org/index.php/FAQs#What_is_a_Xenomai_skin.3F
> which part of this answer does you not understand?

For a beginner there are too many terms that mix in my head, adeos,
rtos... I'm starting to see the big picture now.

>> My guess is it's the way "real time tasks" part looks like/acts like.
>> Am I right?
>> However there is another diagram shown in the Chameleon RTOS pdf -
>> this does not include the user space.
>> What is the user space?
> Which diagram ? on which page of the document?

Page 5. But now when I know that xenomai is more like a nano kernel
approach than thin kernel approach it all makes sense.

>> Can xenomai have multiple skins at the same time?
> Yes Xenomai may have mulitple skins
> (see slide 5 of  http://www.xenomai.org/images/c/c6/Xenomai-OSMB-2007-01.pdf)
> but I don't know if a single application may use different skins at
> the same time.
> I never tried myself so I let other answer that one.
> Why would you want to have/use multiple skin?

I don't. I just wanted to understand how it all works.

I guess for now it is enough questions. I mean I still have plenty but
I guess now I can start finding answers by myself. Thank you.

regards,
-- 
Luke

Re: [Xenomai-help] xenomai on em2440

[Łukasz Sacha]

As I'm reading about xenomai and mini2440 I can see it's gonna be hard
to use xenami 2.6 on my board. This is because I need to have a kernel
that works on my board and such kernels are provided by
friendlyarm.net (git://repo.or.cz/linux-2.6/mini2440.git ). The latest
patched kernel is 2.6.32-rc8 and this one is not supported by xenomai.
I found a kernel 2.6.35-9 patch made by one of the friendlyarm users
but it includes all in one - xenoami 2.5.6 and mini2440 modyfications
(http://www.friendlyarm.net/forum/topic/3299#15471). I think I should
go with this one.
If you can get me a better solution please let me know.
--
Łukasz Dragilla Sacha



On Sun, Oct 30, 2011 at 10:41, Łukasz Sacha <dragilla@domain.hid> wrote:
>> A skin is an API on top of the "thin kernel (ADEOS + Xenomai Nucleus) "
>> which is offered to Real-Time tasks.
>> There is FAQ for that question
>> http://www.xenomai.org/index.php/FAQs#What_is_a_Xenomai_skin.3F
>> which part of this answer does you not understand?
>
> For a beginner there are too many terms that mix in my head, adeos,
> rtos... I'm starting to see the big picture now.
>
>>> My guess is it's the way "real time tasks" part looks like/acts like.
>>> Am I right?
>>> However there is another diagram shown in the Chameleon RTOS pdf -
>>> this does not include the user space.
>>> What is the user space?
>> Which diagram ? on which page of the document?
>
> Page 5. But now when I know that xenomai is more like a nano kernel
> approach than thin kernel approach it all makes sense.
>
>>> Can xenomai have multiple skins at the same time?
>> Yes Xenomai may have mulitple skins
>> (see slide 5 of  http://www.xenomai.org/images/c/c6/Xenomai-OSMB-2007-01.pdf)
>> but I don't know if a single application may use different skins at
>> the same time.
>> I never tried myself so I let other answer that one.
>> Why would you want to have/use multiple skin?
>
> I don't. I just wanted to understand how it all works.
>
> I guess for now it is enough questions. I mean I still have plenty but
> I guess now I can start finding answers by myself. Thank you.
>
> regards,
> --
> Luke
>

Re: [Xenomai-help] xenomai on em2440

[Gilles Chanteperdrix]

On 10/30/2011 10:21 AM, Eric Noulard wrote:
.>> Can xenomai have multiple skins at the same time?
> 
> Yes Xenomai may have mulitple skins
> (see slide 5 of  http://www.xenomai.org/images/c/c6/Xenomai-OSMB-2007-01.pdf)
> but I don't know if a single application may use different skins at
> the same time.
> I never tried myself so I let other answer that one.
> 
> Why would you want to have/use multiple skin?
> 

An application may use multiple skins at the same time.

-- 
                                                                Gilles.