Environment Variable weirdness

[Salman Ahmed <ssahmed@interlog.com>]

(1)
Running Debian 2.1, I noticed sth odd about a couple of 
environment variables (I am running XFree-3.3.3.1-2).

First of all :

    HOSTTYPE=i386-linux

I have a Celeron 300A processor and have installed a new
2.2.12 kernel recently. Where is this variable getting
set from ?

How do I change this env variable on a global basis ?

Same thing for the MACHTYPE env variable :

    MACHTYPE=i386

Why do these variables refer to i386 when the arch
command displays the correct output :

    @phoenix:[/home/ssahmed] arch
    i686


(2)
The other thing is that the DISPLAY env variable is set
to "unix:0.0". My question is : shouldn't this variable
be of the form $HOSTNAME:0.0 ? So why is set to "unix:0.0" ?

And how do I change this env variable on a global basis
(ie for all users) ?


(3)
The last thing is : I'd like to create an environment variable
that contains the following information : kernel version and
machine architechture. e.g. : linux-2.2.12-i686. Let's call
it OSVERSION. Where do I set this environment variable ?

Thanks.


-- 
Salman Ahmed
ssahmed AT interlog DOT com