Distribution Independent Installation

1. http://www.aao.gov.au/local/www/ks/documents/RTAI_Install.pdf (announced on [mailinglist])
2. http://www.fdn.fr/~brouchou/rtai/rtai-doc-prj/installation-guide.html
3. https://mail.rtai.org/pipermail/rtai/2004-October/009072.html

What would be nice here:

1. why are there distribution-specific installation-instructions, when there are also distrib-indep. ones ?
2. what different methods of installation are there (distrib-specific and not ) ?