Re: [ECOS] downloading applications and ecos kernel

[Andrew Lunn <andrew dot lunn at ascom dot ch>]

On Wed, Nov 06, 2002 at 03:24:17PM +0800, Mildred Frisco wrote:
> I have built the ecos net configuration and would like to do the testing.
> The test applications are linked with the whole ecos build, right?  Somebody
> told me that to build new applications with eCos, you have to reflash the
> whole  thing.  What if I want to download two applications or two separate
> functions to the platform?  Can I just put the applications on top of the
> kernel ?
> thanks.

There a few different points in this message.....

You flash Reboot, which is the boot loaded. This you need resident all
the time. 

You then have two main methods of running application code. You can
download it every time using the serial port or ethernet port. Or you
can put your image info flash using redboots fis commands. Normally
for development work you download it every time. For the final product
you will either put it into flash and use a boot script, or possibly
make a ROM application and use that to replace redboot.

No application is linked with the whole ecos build. The linker is
clever enough to leave out parts of eCos that are not used. If you
don't use an API function, it won't be in your image. This results in
smaller images.

eCos is a RTOS, not a desktop OS. The application and eCos are linked
together into one executable, where as an application on Linux, for
example, is not linked with the linux kernel. This means you only run
one application. But, eCos has threads, so if your application has two
separate functions, use two, or more, threads. 

The key thing is to change they way you think about the system. Don't
think desktop machine, multiprocessing, userspace/kernel space. Think
about a tiny system with an RTOS.

      Andrew



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