[okl4-developer] Need assistance in understanding okl4

[Ben Leslie]

On Wed Feb 06, 2008 at 10:02:45 -0800, D.V.Sandeep wrote:
>Hi Jorge Torres,
>   
>  Thank you very much for your elobrated mail
>   
>  I have gone through the Ok labs site, I could find no better user manual than the one l4uman_X2.pdf (Document Version 1.6 of 14th July 2004)and unfortunately there are many sections starting from 2.3 L4 Architecture which are empty.
>  Could you please provide me the latest USER MANUAL/ http link and also if possible provide me any documention you have it on L4.

http://wiki.ok-labs.com/images/a/af/Okl4-progmanual.pdf
   
>  I have questions on you email
>   
>  1) What is ment by platform & architecture I dont understand the difference between them?

An architecture is a particular instruction set. For example, MIPS32,
ARMv5, ARMv6. A platform is a specific system-on-a-chip implementation

>  2) I dont understand the difference between ABI (???)& API(application program interface)

The ABI is the application binary interface. This specifies the 
exact way in which to modules of software interact. In this case
the OKL4 kernel, and an OKL4 program. In most cases as a user
you do not need to worry about the underlying binary details.
This is only necessary if you are writing a library or a tool which
directly interfaces with the kernel.

The API is the application programming interface. This is generally
what a programmer uses to interface to a particular library or
system, in our case the OKL4 kernel. The API is defined in terms
of a particular language, specifically C. The API documentation
describes what all the specific specific API-s do.

>  3) please explain me the phrases about tools marked red in your email.

Sorry, I'm on text only email here, not sure which bits are red ;)
   
>  4) Does Iguana and L4Linux are in different protection domains.How do we manage the inter-domain critical sections.

OKL4's root-server (Iguana) is in a different protection domain to OK Linux.

By design we avoid inter-domain critical sections, as we think this is better
implemented by communicating servers.

It would be possible however to use either sync IPC, or async notify to 
create a inter-domain critical section.

Cheers,

Ben