[okl4-developer] Different questions about OKL4

[Abi Nourai]

Hi Alexander,

Here's some answers I drafted to your email whilst traveling.  It was  
a noble thought at the time that I'd find more time to finish these  
answers.  But alas.  Sending what I have in hope that a partial  
response will still be useful.

On 22/01/2009, at 10:57 AM, Alexander Valitov wrote:
>
>
> Regarding Elfweaver:
>
> 1. Recently I’ve read Elfweaver reference manual
> (elfweaver-ref-manual-3.0.pdf), but I still have a lot of blind  
> spots about
> Elfweaver. Are there any documents or guides which explain main  
> concepts and
> give some rationales? Or tutorial for Elfweaver script from simple
> application (e.g. single cell) to really complicated (e.g. several  
> OKLinux
> instances with separate OKL4lib cell and native L4 cell)?

Having a look at the weaver files that ship with the example cell  
configurations (which include a single-cell example) should be helpful.

>
>
> Iguana vs OKL4lib:
>
> 2. OKL4lib manual (okl4lib-ref-manual-3.0.pdf) says: “OKL4 Library is
> intended to be a complete replacement of Iguana and other root  
> servers”.
> Does it mean that we could consider Iguana as out-of-date module and  
> it is
> wise not to spend time becoming familiar with the Iguana? Are you  
> going to
> remove the Iguana in future releases? Is the OKL4lib going to become  
> a sort
> of default OS personality for OKL4 L4 kernel?

Iguana has been decommissioned starting with OKL4 3.0.  So yes,  
consider it outdated. Even better, pretend it never existed !

libokl4 is the interface you should be targeting when developing Cells  
for OKL4 3.0.

libokl4 is a library that interfaces directly with OKL4.  Iguana was  
implemented as a server and it's services invoked effectively via RPC.

I wouldn't consider libokl4 an OS personality.  More of an API that  
provides the ground work for implementing various OS personalities and  
building Cells in general.

> Build system options/description:
>
> 3. Unfortunately I’m not familiar with SCons build system and even  
> with
> Python itself. That is why your building system looks really tricky  
> for me.
> Also build options description given at
> http://wiki.ok-labs.com/BuildingAndSimulating wiki   seems to be out  
> of
> date. Is there any document which describes available build system  
> options
> and gives some instructions how to use build system?

You don't need to care or think about SCons at all.  The SCons build  
system is something OK's R&D team uses to generate clean, easy to use,  
SDKs for users of OKL4.  When it comes to building systems on top of  
OKL4, work with the SDK directly, and not the source tarball or it's  
associated build system.  The SDK ships with some examples of systems  
(sets of cells) that are built with standard Makefiles.

It's possible that some of the documentation on the wiki is pre-sdk- 
era and therefore not providing the best advice.

>
> 6. As I understood OKLinux is Iguana application. Is it possible to  
> get
> OKLinux running on top of OKL4lib?

This is the case starting with OKL4 3.0.  There's no iguana at all in  
the latest release.

>
> 11. I think pthread is great effort. But unfortunately it is not  
> enough for
> porting POSIX application. Do you have any plans for implementation  
> of at
> least Minimal Realtime System Profile AKA PSE51? Any approximate date?

Sure.  We'd be very interested in your ideas on what functionality in  
PSE51 you are most eager to see.

BR, Abi