*Takes big breath*

> 1. Does anybody know how to seriously trim the Linux kernel and 
> configure it for close to real-time driver response?? Apparently, it is 
> agreed here we must all just accept current distros.
>

I can help you configure a kernel to have minimal functionality. It is not
that hard. It will still be a protected OS with access permissions and proper
scheduling. And it does not mean that it will not be a good real-time system.

If your task is sufficiently simple, you can do it with a microcontroller
which is a lot more robust and a lot more suitable for real-time systems.
I coded an audio pipeline based on ALSA and POSIX threads and the real-timeness
of it is remarkable. I was shooting for a real-time audio sequencer.


> 2. Does anybody know how to use a simplified XWindow toolkit for close 
> to real-time response?? Apparently, some feel OpenGl or some network 
> add-ons is the GUI of choice.
>

Yes. You need to decouple the graphics from the "engine" of what you are
trying to do. I can do it with POSIX threads. What you really want is to not
have the graphics (and whatever lag goes with processing events) affect your
real-time performance of the engine. It can be done. It is a question of
architecting the communication of the engine thread with the graphics thread.
I like to do stuff like that with unix pipes, where you have one thread write
into the pipe and the other one read it. The reason is that you can leave the
data waiting there (buffered) if the thread that is intended to read it does
not get to it at the right time. It avoids MUTEXes, which would give you
stalls and kill your real-timeness. Does all this make sense? I can provide
with example code in C.

 
> 3. I've suggested car analyzers as an interesting, useful Linux 
> beginning application. And some programming languages that might be helpful.
>

Embedded systems are mostly state machines and that is what microcontrollers
are. There are a LOT of people who program real-time systems on off-the-shelf
microcontrollers, and I can introduce you to some of them. Car analyzers, the
way I understand your terminology, can be either an embedded system or a proper
OS. I have examples for both. Go to www.nefmoto.com and you will find both.


I can spare little time to work on other people's projects, but I can certainly
try to point you in the right direction if it is something that falls within
my reach. That is what lists like this one are about...