Re: Thoughts on EMC's design and implemenation

[Paul <paul.corner-at-tesco.net>]

Hi Jon

Realtime code must be written in plain C and not linked to any external 
libraries. This has nothing to do with legacy RT support, but rather the way 
the kernel works. Realtime modules can be considered loadable kernel modules 
to all intents and purposes. 
At boot time, the kernel has no idea where to find various libraries, nor 
does it know which devices are going to be mounted. So, untill the assortment 
of boot scripts have been run to configure the system, the kernel must be 
self contained. Once the file system has been mounted, loadable modules can 
then be found and used if needed.
These modules can not call upon external libraries either - Just imagine the 
sort of chaos that would occur if you used an initrd boot (or deleted one of 
the libraries).

Regards, Paul.


P.S. A read of linux/Documentation/CodingStyle is worthwhile.


On Tuesday 10 Sep 2002 6:26 am, Jon Elson wrote:
>  I know that C has been the
>
> > typical language to write this kind of software in but C++ is getting
> > more and more popular across the board.
>
> Most of EMC IS in C++.  The real-time section is in plain C for some reason
> having to do with older RT patch support.