[ECOS] Chained ecos applications

[Nick Garnett]

Håvard Harstad <hh@systemsoft.no> writes:

> Hi,
> 
> I have successfully been able to start one ecos application from redboot using 
> the load and go commands. No I want to try to start a second ecos application 
> when the first ecos application has finished. What I try to do is:
> 1. Start redboot.
> 2. Start “Ecos application 1” using load and go commands.
> 3. Start “Ecos application 2” when “Ecos application 1” is finished.
> 
> Is this possible to do with redboot and ecos?
> 
> It is not a solution to combine “Ecos application 1” and “Ecos application 2” 
> to one ecos application using two threads, because the “Ecos application 2” 
> executable can be updated independently of “Ecos application 1”.

That may work on some platforms, but it is not guaranteed. The problem
is that the first application could have made all sorts of arbitrary
changes to the hardware that may interfere with the second
application. The only safe way of getting the machine back into a
known state is to apply a hard reset.

The working model for redBoot is that it loads a program and then
gives the machine to it. It doesn't generally expect to regain control
except as a result of debug activity. Some support has been added
recently to permit stand-alone programs to exit back to RedBoot. But
these must be very well-behaved, and it is unlikely to work for eCos
applications.

-- 
Nick Garnett                    eCos Kernel Architect
http://www.ecoscentric.com      The eCos and RedBoot experts


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