Re: [ECOS] Multiple Inheritance used in eCos class Cyg_Thread

[Donald Walton <dwalton at dramail dot com>]

Thanks for your insightful response.

I'll pass the responses along to my bosses and see which way they want
to process from here.

Have a great day,
Don Walton

On Thu, 2006-12-14 at 16:14 +0000, Nick Garnett wrote:
> Donald Walton <dwalton@dramail.com> writes:
> 
> > I would be interested to know the type of testing eCos has been through.
> > If it has been successfully tested as part of an embedded aviation
> > system, I would agree with you.  If it has been tested as part of the
> > embedded system for a printer or digital camera, I would have to
> > disagree with you.
> 
> eCos has been used is a number of mission critical applications
> including automotive and satellite systems. It has certainly been used
> in aviation, but probably not in anything safety critical.
> 
> > 
> > When it comes to developing embedded systems that are safety critical,
> > one cannot be too careful.
> > 
> > If there is little interest in using eCos in safety critical systems,
> > leave it as it is.  However, companies and individuals planning to use
> > it in areas where safety is important may want to rework the area where
> > there is multiple inheritance or plan to accept the cost of extensive
> > testing.  In such situations, this can be an additional risk factor for
> > a project.
> 
> The edict against multiple inheritance is presumably against using it
> to develop new application code. In the case of eCos, MI is used only
> within the kernel, applications do not have access to the classes
> involved, and it is used in a very restricted and controlled
> way. There is absolutely no possibility of application code
> encountering MI under normal circumstances.
> 
> Looking at it a different way: if eCos were a closed source OS,
> distributed only as a binary library, then you would not know that MI
> were being used internally. The same is true now, even though you can
> see the source, the use of MI is not visible.
> 
> Very little development now goes on in the kernel, it has been stable
> for many years. So the fear that some sort of programming mistake
> using MI will introduce a bug is very remote. Changing the kernel to
> eliminate MI is much more likely to destabilize it.
> 
> 
> -- 
> Nick Garnett                                     eCos Kernel Architect
> http://www.ecoscentric.com                The eCos and RedBoot experts
> 
> 

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