Mama, I can understand it's tedious to go through the whole FAI-Guide and try to understand FAI bit-by-bit without hands-on experience.
If you want to start understanding the classes concept in FAI I would suggest you check out two/three things: 1.) The FAI config space (e.g. of the default FAI setup): As a rule of thumb, every CAPITAL file name oder directory refers to a CLASS (i.e. is a class name). This may start to give you an idea. * Directory names in the "files" folder in the level above the file with CLASS names are the files that FAI copies (a separate version per CLASS is possible). * The "scripts" directory contains 'CLASS name' directories, which contain scripts that are executed when the class is active. * The "50-host-classes" script in the "class" directory of the config space demonstrates a way how to define the classes active in an installation, simply echoing the class name. Have a look at it. 2.) Start at this overview graphic: http://faiwiki.informatik.uni-koeln.de/index.php/FAI_Installation_Overview The explanations below it will make you understand more, and also contain a link to the FAI-Guide chapter that explains "hooks" in detail (which are basically scripts that can be made to execute for each stage of installation). 3.) Check out the Howto/Tutorial/User Manual categories in the FAIwiki if you have specific problems. Many/some questions you come across have been asked (and solved) before, and are documented there: http://faiwiki.informatik.uni-koeln.de/index.php/Special:Categories This should be sufficient to get you started. Peter Am Donnerstag, den 23.09.2010, 14:22 +0200 schrieb mamadou diop: > Right. I haven't seen this thing in the documentation but from the > internet. In a tutorial on FAI, > someone had added the package 'python' at the top group > of /etc/fai/NFSROOT. The only things > i don't understand very well on FAI are the classes and hooks > concepts. Because i haven't learned the > shell, expect, perl nor cfengine programming.